Dissertations / Theses: 'Coastal Lagoon'

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Nandi, Nandi. "The Ecological Dynamics of a Coastal Lagoon." Doctoral thesis, Universitätsbibliothek Leipzig, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-161001.

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A coastal lagoon is a landform that is influenced by natural processes and human activities. All human activities at the upstream, particularly agriculture and cultivation bring soil, waste, and other materials to the downstream area through the river drains into the lagoon. Even though its position is inland of water bodies, the lagoon is still affected by waves and winds from the sea. Additionally, coastal lagoon will be the depository place for sedimentation from the upland area. Segara Anakan (SA), which is located in Indonesia, is an example of a coastal lagoon area, which has a unique biophysical characteristic. The region has a great natural ability to ensure the sustainability of the interrelationships between terrestrial, estuarine and marine ecosystems in harmony and balance as a habitat for flora and fauna. The region is an area of migration of various types of protected animals and it is a place of breeding for diverse species of the shrimp and fish, which have a highly economical value. Segara Anakan lagoon (SAL), currently experiencing acceleration narrowed on its area due to a very intensive sedimentation from the mainland. The research aims to answer the question of how ecological dynamic occurs in the SAL area due to sedimentation. Achieving the objectives of this study required examining the morphology and land use changes with multitemporal remote sensing approaches. While, to assess the role of community participation and planning management strategies is using qualitative descriptive methods and SWOT analyze. The using of multitemporal remote sensing Landsat images is possible to analyze the morphological and land use changes with different time and sensors. These Landsat has image accuracy about 92.66%. It can be used for image interpretations resulting 13 classes of land use. The morphodynamics of SAL indicated by the changes of area of lagoon and accreted land and also the distance of coastlines during the periods 1979-2013. In addition, the land use or land cover also changes during that time. The bigger portions of land use changes are in the tropical and mangrove\'s forests. There are distinctive forms of participation in conservation efforts. The upstream community involvement in conservation tends to be different participating in the way of ideas, money, materials, properties, skills and expertise or social activities. In addition, the community at downstream area has a sufficiently high level of participation in environmental conservation. There are also strong relationships between the level of education and level of income and basic knowledge in conservation with the participation of SA conservation. The ecological dynamics of the SAL area are described with a historical time line. It is divided into three time periods: the 1970s - 1980s, the 1990s and from 2000 onwards. Each of these has occurrences that can lead to changes in the environment. The implementation of appropriate conservation technique can reduce the sedimentation rate. Hence, the synergic coordination measures between upstream and downstream regions are necessary in the future. Increasing community awareness and participation in the conservation by improving educational sector, providing information, and applying sustainable development land use are the ways to match human activities with the temporal and spatial dynamics of the coastal resources.

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Murphy, Robert F. "Fish assemblage structure in Maryland's coastal lagoon complex." College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/3007.

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Thesis (M.S.) -- University of Maryland, College Park, 2005.
Thesis research directed by: Marine, Estuarine, Environmental Sciences Graduate Program. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

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Ford, Kathryn Hale. "Assessment of the Rhode Island coastal lagoon ecosystem /." View online ; access limited to URI, 2003. http://0-wwwlib.umi.com.helin.uri.edu/dissertations/dlnow/3115628.

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Fernandes, Elisa Helena. "Modelling the hydrodynamics of the Patos Lagoon, Brazil." Thesis, University of Plymouth, 2001. http://hdl.handle.net/10026.1/679.

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The Patos Lagoon, the largest choked coastal lagoon in the world, is a typical centre of population, commerce, industry and recreation, and consequently it is also a site for disposal of industrial, agricultural and municipal wastes. Important questions concerning beneficial uses of and potential changes to the lagoon and its estuary are left unanswered without a good understanding of hydrodynamic processes. The current study involves the choice, calibration and application of a numerical model which can be used in future hydrodynamic, sediment transport and water quality studies in the area. The two- and three-dimensional modes of the TELEMAC System were chosen to study the hydrodynamics of the Patos Lagoon. In order to calibrate the TELEMAC-2D model for the lagoon, measurements of salinity, current speed and direction, water elevation and wind speed and direction were carried out simultaneously at three stations in the estuarine area during three days. The model validation was carried out against an independent data set from the 1998 El Nino event. Several two-dimensional simulations were carried out to investigate the main processes controlling the Patos Lagoon hydrodynamics. The model was forced with prescribed river inflow at the top of the lagoon, wind stress at the surface and water elevation at the ocean boundary. The barotropic pressure gradients established between the lagoon and the coastal area as a result of local and remote wind combined with the freshwater discharge, proved to be the main forces controlling the lagoon subtidal circulation, as well as the exchanges between the lagoon and the coast. The local wind dominates the lagoon circulation through the set-up/set-down mechanism of oscillation, whereas the non-local wind drives the circulation in the lower estuary. The entrance channel acts as a filter and strongly reduces tidal and subtidal oscillations generated offshore. Three-dimensional simulations proved to be essential. Studies of the processes involved in the estuarine transverse circulation showed that the wind drives the lateral flow in the shallow areas, whereas in the channel it depends on lateral pressure gradients and channel curvature and geometry. Insights on the estuarine baroclinic circulation indicate the barotropic forces as the main mechanism controlling salt water penetration and salinity structure in the estuary. This study produced valuable information into the forces controlling the circulation of the Patos Lagoon and its estuary. Important issues regarding the capabilities of the TELEMAC System twoand three-dimensional modules were explored, producing a valuable tool for further hydrodynamic and sediment transport numerical modelling experiments.

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Newton, Alice. "The water quality of the Ria Formosa Lagoon, Portugal." Thesis, Bangor University, 1995. https://research.bangor.ac.uk/portal/en/theses/the-water-quality-of-the-ria-formosa-lagoon-portugal(79befc15-900b-452f-9d1e-24d6f8315559).html.

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The Ria Formosa is a lagoon on the South coast of the Algarve, Portugal and insulates SS km of the coastline from the full impact of the Atlantic. A review of the lagoon considers its geomorphology, sedimentology, hydrography, water quality and ecology. The Ria Formosa is identified as an important regional and national resource with respect to recreation, tourism, fishing, aquaculture, shipping and salt extraction. Ma*or regional developments in the form of spreading urbanisation and intensified agriculture, together with rising numbers in both the resident population and the annual tourist influx, pose an ever increasing stress upon the lagoon system, particularly with respect to water quality. The region contiguous to the lagoon is devoid of heavy industries and the review concludes that the greatest threat to sustained development of the lagoon resources is a progressive deterioration of water quality promoted by ever increasing discharges of nutrient and organic rich sewage effluent. In consequence, this study of the water quality in the Ria Formosa focuses upon the spatial and temporal variability in the nutrient and dissolved oxygen fields. Hydrographic, nutrient and dissolved oxygen data captured during three separate sampfing programmes are presented and discussed. The first programme addressed the variability in the lagoon as a whole. From June 1987 to May 1988 hydrographic, nutrient and dissolved oxygen data were collected at monthly intervals from sixteen sampling stations distributed through the lagoon. All sampling events were coincident with high and low water on neap tides. This sequence of surveys showed that during the winter the lagoon acts as a typical estuary but for several months during the hot, dry summer the salinity of the waters within the lagoon exceeds that of the seaward boundary. No evidence of either marked or persistent stratification was found. Despite strong tidal flushing, the waters within the lagoon are not homogenous and the characteristics of the incoming coastal water are significantly modified in the inner reaches. Principal Component Analysis divided the sixteen sampling stations into four groups: (i) stations in the outer lagoon where water characteristics are little modified by the inner lagoon processes and sources; (ii) intermediate stations with water characteristics dominated by the inflowing seawater 11 but somewhat modified by inner lagoon processes and/or sources; (iii) estuarine stations where the water properties are greatly influenced by freshwater inputs; (iv) inner lagoon stations insufficiently flushed by tidal exchange and partly influenced by inner lagoon processes and sources. Stations comprising the latter group (in the vicinity of the city of Faro, the West end and the East end of the lagoon) all exhibited characteristics symptomatic of a marked reduction in water quality. These were manifest to a greater extent at the station adjacent to Faro. A comparison of the range of nutrient concentrations in the Ria Formosa with other lagoon systems identifies it as being one of the most nutrient enriched. It is concluded, however, that good water quality prevails throughout most of the lagoon at all times of the year and that the presence of, or potential for, adverse water quality is localised in particular areas. The objective of the second sampling programme was to generate a temporal record of the extent to which the properties of the coastal waters entering the lagoon were modified in the western inner reaches of the lagoon. Samples were taken weekly on Springs and Neap tides throughout 1989 coincident with high water at the coastal station and at low water in the lagoon. The offshore water showed a strong seasonal signal with an abrupt change of water type in autumn. Throughout the year, the lagoon water was consistently and significantly enriched in silicate relative to the seawater, but also with respect to ammonium and nitrite in winter. In contrast there was no evidence of an internal source of nitrate. Almost half of the morning samples showed the lagoon water to be less than 80% saturated in dissolved oxygen on most occasions during the summer months. Hypersaturation in summer afternoon samples exceeded the range recommended by European Union directives for water quality. The third sampling programme addressed short term variability of water characteristics at the western end of the lagoon. Observations every thirty minutes during the Extreme Spring Tide cycle of the autumn equinox showed that water from other parts of the lagoon (sewage contaminated water and water flushed off salt marshes) was flushed past the station during a tidal cycle. Percentage saturations of dissolved oxygen reached an early morning minimum of 54%. The nutrient and III dissolved oxygen observations indicated that the water quality situation in the western part of the lagoon was precarious. A set of circumstances which would provoke mass mortality of the biota under the conditions at the time of the study is outlined. The conditions in the Ria Formosa were compared to other lagoons and it was concluded that the Ria Formosa is relatively nutrient rich.

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Kain, Claire Louise. "Past, Present and Future: Morphology and Dynamics of Rivermouth Lagoons in Westland, New Zealand." Thesis, University of Canterbury. Geography, 2009. http://hdl.handle.net/10092/4012.

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Coastal wetlands and rivermouth lagoons are dynamic systems, which respond rapidly to sea-level, tectonic, meteorological, anthropogenic and other synergistic drivers. This research used a multi-disciplinary approach to investigate two representative West Coast lagoon systems (Totara Lagoon and the Shearer Swamp-Waikoriri Lagoon Complex) in order to document their present-day geomorphology and determine the development and processes acting on these systems over historical time. This information was then used to predict their future under varying climate, development and management pressures. In addition to adding to the West Coast knowledge base, the findings of this research are applicable to similar systems elsewhere in New Zealand and internationally. This investigation used a multidisciplinary approach to investigate the dynamics, structure, development and active processes in the two study systems. Techniques to document current hydrology and topography included hydrological records of water level, temperature and conductivity, and Global Navigation Satellite Surveys (GNSS). Outlet dynamics over a decadal scale were investigated through temporal aerial photograph analysis, and sediment core analyses showed changes occurring over longer timescales. Significant differences in morphology and dynamics were observed between Totara Lagoon and Waikoriri Lagoon, with the former being much larger, more stable, and less dynamic in terms of dune morphology and outlet migratory patterns. Hydrologically, Totara Lagoon is currently in an estuarine phase, and experiences significant tidal inflows, which demonstrates the connectivity between definitions of coastal lagoons and estuaries. Waikoriri Lagoon is freshwater, and can be described as a hapua-type system, but exhibits very different river flow and barrier composition to East Coast examples. Sediment core analyses from Shearer Swamp and northern Totara Lagoon showed little change over a decadal to centennial scale, but evidence of a change in margin dynamics in response to farming and stabilisation of adjacent dune ridges was observed in Shearer Swamp. Results suggest landward migration of the southern end of Totara Lagoon occurred over this timeframe. The future of these systems depends on the interaction between climate and anthropogenic (including management) factors. A conceptual model of process and response suggests three possible resultant scenarios: lagoon loss, natural lagoon, or artificially modified lagoon. A significant finding of this research is the recognition that some systems exist on a continuum between a hapua and an estuary, switching hydrological states through time while maintaining consistent morphology. In addition, the importance of barrier permeability in hapua formation is highlighted, and the term ‘sandy hapua’ introduced to distinguish these low-flow systems with low barrier permeability from the typical mixed sand and gravel examples documented on the East Coast. These findings enhance scientific understanding of rivermouth lagoon systems, and demonstrate the wide spectrum of conditions under which they may form. This process-based understanding is important from a coastal management perspective as concerns of human induced climate change and accelerated sea level rise grow.

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Ireland, Stephen. "Holocene coastal changes in Rio de Janeiro state, Brazil." Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6328/.

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Evidence of Holocene sea-level changes along the Rio de Janeiro State Coast, and for the evolution of coastal lagoons and barriers in response to these sea- level movements, has been examined using stratigraphical and micropalaeontological techniques, radiocarbon dating and published data. Present-day diatom death assemblages have been studied in order to facilitate the interpretation of fossil assemblages, which has inter aha permitted the development of a simple statistical technique for the evaluation of the allochthonous diatom component. Modern lagoonal tide- gauge data have been used to establish a relationship between lagoonal water levels and tidal levels on the open coast. Evidence is presented which indicates that barriers which were previously believed to date from the mid-Holocene formed during the 'Last' Interglacial. The history of true Holocene barriers has been shown to be relatively complex, with some barriers having migrated by over-stepping and others by continous shoreface retreat. The published Holocene sea-level maximum for Rio de Janeiro State of -t- 4.8 m at 5100 BP is considered to be in error (approximately 3.0 m too high at this time) and a maximum Holocene sea level of -t- 3.0 m at c. 4000 BP is preferred. The evidence for sea-level maxima in other parts of Brazil at 5150 BP and for the migration of the geoid surface during the Holocene is questioned and shown to require further study. It is tentatively suggested that there may be evidence for an interglacial sea-level high at c. 35000 BP in Rio de Janeiro State.

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Barnes, Natalie. "The nematode ecology of a UK coastal saline lagoon system." Thesis, University of Southampton, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402227.

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Desjardins, Amos Adam. "Paleoenvironmental Reconstruction of a Coastal Lagoon in Southwestern Dominican Republic." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/33776.

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The study of lake sediments can provide valuable insights into lake history and climate variation throughout time. In-depth studies have been carried out at Lake Miragoane, Haiti and in high- and mid-elevation sites in the Dominican Republic, and a few other inland and coastal locations throughout the Caribbean; however, to date little has been published on prehistoric conditions in other coastal areas of Hispaniola. Laguna Alejandro (informally named by researchers) (~18.31Â°N, 71.03Â°W), on the southwest coast of the Dominican Republic, was examined to expand our knowledge of long-term environmental history in this region. This ~25 hectare lake is separated from the Caribbean Sea by a 100 m wide limestone ridge about 3â 5 m tall. We recovered two consecutive cores (0â 100 cm, 100â 185.5 cm) close to the limestone barrier to investigate the potential for paleotempestology and other paleoenvironmental reconstructions. Three AMS 14C dates indicate that the lake is ~1100 years in age. Sediment analyses revealed three major events that correlate with bands of uncharacteristic sediment composition and particle size at 74â 77.5 cm, 150.5â 153 cm, and 183.5â 185.5 cm. Four distinct strata containing serpulids and several pockets of Ammonia beccarii provided insights on changes in salinity and the connections between the lagoon and the ocean. The upper deposit (74â 77.5 cm, 620 Â±60 YBP) contains gypsum and represents a period of increased salinity within the lake brought on by drought. The two lower bands are composed of sand consistent with nearby beach sands. The 150.5â 153 cm band provides evidence of a hurricane landfall at 1022 Â± 60 YBP. The combination of biological data from 165â 183.5 cm and sediments within the 183.5â 185.5 cm band provide evidence for salinity fluctuations that indicate the closure of the lake. Sediments contained a variety of invertebrates that helped to document changes in lake chemistry through time. This study of Laguna Alejandro sediments documented lake history and provided information on recent climatic shifts in the region.
Master of Science

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Jackson, Kelly London. "Paleotsunami History Recorded in Holocene Coastal Lagoon Sediments, Southeastern Sri Lanka." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_theses/171.

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Tsunamis are low amplitude, large wavelength waves that can significantly impact coastal regions. Although their destructive impacts are clear from recent events, the frequency with which tsunamis occur is less well constrained. To better understand the tsunami history and coastal impacts in Sri Lanka, this study compares sediments deposited by the December 26, 2004, tsunami to older lagoon sediments in search of evidence for paleotsunami deposits. Results from this study illustrate that the coastal lagoons in Sri Lanka preserve tsunami deposits and can provide the first steps towards constraining the paleotsunami history of the Indian Ocean. Because Sri Lanka is a far field location relative to the Sumatra-Andaman subduction zone, the preserved tsunami deposits are likely mega-tsunami events similar in size and destruction to the December 26, 2004, tsunami. The December 26, 2004, M 9.1?9.3 Sumatra-Andaman earthquake generated a massive tsunami that propagated throughout the Indian Ocean, causing extreme coastal inundation and destruction. The southeastern coastline of Sri Lanka was impacted by the 2004 tsunami where between one and three waves inundated coastal villages, lagoons, and lowlands, killing more than 35,000 people. Karagan Lagoon, located on the southeastern coast of Sri Lanka, was impacted by two waves from this tsunami. Although the lagoon commonly is dominated by organic-rich, siliciclastic clays, silts, and fine sands, the 2004 tsunami deposited a distinct layer of coarse quartz-dominated sand between 1 and 22 cm thick. The base of the 2004 deposit is sharp and erosional and some layers feature faint subparallel laminations. The 2004 tsunami deposit is generally continuous, fines landward, and is confined to the eastern portion of Karagan Lagoon, in the direction from which the tsunami arrived. Sri Lankan lore, in conjunction with reconstructed historical earthquake data, suggests that other tsunamis likely affected Sri Lanka in the past. To test this, twenty-two 1?4 m sediment cores were collected from Karagan Lagoon, providing key information for unraveling the pre-2004 tsunami history of southeastern Sri Lanka. At depth, sixteen cores from Karagan Lagoon contain as many as ten distinct sand layers, including the deposit from the 2004 tsunami. These cores feature siliciclastic clays, silts, and fine sands that dominate the background lagoonal sedimentation that are punctuated by coarse sand layers. These sand-rich layers feature sharp, erosional bases, coarsen and fine upwards, vary in thickness from 1 to 22 cm, and include varying percentages of fine to very coarse sand, with a low-abundance of silt and clay. In the best constrained interval, three coarse sand layers include composition, grain size, grading, and sedimentary structures similar to the sediments deposited by the December 26, 2004, tsunami. The layers are identified in five of the twenty-two cores, although the thicknesses vary. Six additional less well constrained sand layers are present in four of the twenty-two cores. Cores located closer to the lagoon mouth and the eastern coastline (the direction from which the 2004 tsunami arrived) contain more sand layers than cores farther away from the tsunami wave entry point. On the basis of their sedimentary structures, geometry, and extent, these sandy layers are interpreted to represent paleotsunami deposits. AMS radiocarbon dating was used to date the bulk organic sediment from above, between, and below the ten paleotsunami layers in sediment cores from Karagan Lagoon to constrain the timing of events in southeastern Sri Lanka. Material from within the deposit was not dated because it was likely transported from various sources during the event and thus does not represent the age of the tsunami. AMS radiocarbon dates from above and below the paleotsunami layers were calibrated from radiocarbon years before present to calendar years before present (Cal YBP) using OxCal v. 4.0 (Bronk Ramsey, 1995; Bronk Ramsey, 2001) with calibration curve IntCal04 (Reimer et al., 2004). The constraining time intervals of tsunami deposits II?VI were averaged to yield deposits of ages 226, 1641, 4198, 4457, 4924 Cal YBP. Tsunamis VII?X only had sediment dated immediately below the deposit and therefore were deposited prior to 6249, 6455, 6665, and 6840 Cal YBP. In total, ten tsunami deposits, including the 2004 event, are preserved in Karagan Lagoon on the southeastern coast of Sri Lanka. The Karagan Lagoon paleotsunami deposits provide constraints on the recurrence interval of tsunamis similar in magnitude to the 2004 event. The uppermost paleotsunami units were deposited 226, 1641, 4198, 4457, and 4924 Cal YBP, based on AMS radiocarbon dating. Thus, including the 2004 event, six tsunamis affected Karagan Lagoon in the past 5500 years, yielding a recurrence interval of approximately 916 years. Three of the six events, however, occur between ~4000 and 5500 years yielding a recurrence interval of approximately 500 years for this 1500 year period. Four additional older paleotsunami deposits occur in the deeper sections of the cores and were deposited prior to 6249, 6455, 6665, and 6840 Cal YBP, yielding a recurrence interval of approximately 200 years for this time period. Assuming that Karagan Lagoon contains a complete record of tsunami events, the recurrence of tsunamis similar in magnitude to the December 26, 2004, event can occur as often as 200 years. This ?recurrence interval? is illustrated by our data for the time period with increased tsunami activity from ~4000 to 7000 Cal YBP. Tsunamis may potentially affect Sri Lanka at relatively high frequency during certain time intervals though the overall recurrence pattern of these events displays a highly irregular distribution. This extreme variability needs to be taken into consideration when such events are related to earthquake recurrence intervals. Prior to the December 26, 2004, tsunami, paleotsunami deposits in the Indian Ocean were largely unstudied and consequently, Holocene tsunami chronology was incompletely understood for the Indian Ocean. The results from this study represents the first geologic evidence of paleotsunami deposits in Sri Lanka generated by tsunamis during the past 7000 years. The identification of these paleotsunami deposits illustrates that the 2004 tsunami was not a ?one-time event,? but in fact has ancient counterparts.

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McCallum, Roisin. "Organic matter and nitrogen cycling in a heavily modified coastal lagoon." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2022. https://ro.ecu.edu.au/theses/2552.

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Coastal waterbodies and their catchments have been highly modified, leading to altered flushing and eutrophication. Strategies to manage water flow to either maintain water levels or reduce salt-water intrusion and mitigate impacts to coastal waterbodies include engineering approaches such as the construction of surge barriers and river diversions and manipulation of sandbars. Climate change is increasingly impacting coastal waterbodies with predictions of increased drying and significant changes to rainfall patterns. Consequently, engineering management strategies are likely to increase, but it is unclear how biogeochemistry and benthic cycling in coastal waterbodies will be affected, and how to manage the likely eutrophication issues that ensue. Therefore, the aim of this project was to determine how organic matter and nutrients are transported and cycled within a heavily modified intermittently closed/open lakes and lagoons (ICOLL). The Vasse Wonnerup Wetland System (VWWS) is a modified eutrophic ICOLL in southwestern Australia. It has been managed for over 100 years and has multiple surge barriers, river diversions, an oxygenation plant, and an artificially managed sandbar. In addition, significant portions of the VWWS seasonally dry out, making it an ideal system to study the effects of climate change to coastal systems which are likely to experience similar modifications as the VWWS. Stable isotope analyses and mixing models showed that the particulate organic matter (POM) in the system is derived mainly from autochthonous sources (fringing vegetation and aquatic macrophytes). Similarly, compound-specific stable isotopes showed that the sources of dissolved organic matter (DOM) are mainly autochthonous and dominated by dissolved organic nitrogen (DON). The extremely low ( < detection limit) concentrations of dissolved inorganic nitrogen (DIN; nitrate and ammonium) in the basin water column suggests that DON is crucial to sustaining a DIN supply in the VWWS through decomposition and tight cycling between DON and DIN. Currently, national and international management guidelines focus on inorganic nutrient concentrations as indicators of unacceptable concentrations (trigger values) and management strategies are generally focused upon reducing allochthonous (external) dissolved inorganic nutrients (i.e., nitrate, ammonium, and phosphate). This study shows that the focus of management on inorganic nutrients may not be well placed in this type of system. Benthic flux experiments demonstrated that water column DO and seasonal drying of the sediment did not affect dissolved organic C, N or P fluxes significantly but did influence benthic metabolism with higher rates occurring in high water column DO conditions. Despite this, benthic metabolism remained anaerobic. Surprisingly, decreasing water column DO did not influence net greenhouse gas (GHG) emissions indicating increasing water column DO will not decrease GHG emissions. Oxygenation of the water column did increase N removal, with higher net N2 effluxes with increasing water column DO. Bioavailable nitrogen pools the water column were supplemented in low DO conditions by N2O, with consumption of N2O occurring during dark hours. The lack of significant effects from DO manipulation treatments on many of the measured nutrient species indicate that maintenance of water column oxic conditions, regardless of the concentrations are unlikely to be effective in promoting removal or storage of nutrients in eutrophic systems. Increasing drying out of coastal waterbodies will have impacts on benthic metabolism, however this issue may become system specific depending on sandbar and surge barrier management strategies influencing water levels. Overall, this study confirmed the importance of autochthonous OM contributions and cycling in an ICOLL, whilst highlighting the impacts of engineered modifications in this type of coastal waterbody and its catchment.

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Avois-Jacquet, Carol. "Variabilité spatiale multiéchelle du zooplancton dans un lagoon récifal côtier (Multiscale spatial variability of zooplankton in a coastal reef lagoon)." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2002. http://tel.archives-ouvertes.fr/tel-00001767.

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Variabilité spatiale multiéchelle du zooplancton dans un lagoon récifal côtier - L'identification des changements dans les patrons écologiques selon l'échelle spatiale et la compréhension des processus qui génèrent ces changements sont d'une importance considérable en océanographie. Dans ce contexte, comprendre comment une communauté biologique répond à l'hétérogénéité environnementale requiert la connaissance des processus impliqués et l'échelle spatiale à laquelle ils opèrent. Les relations spatiales entre la variabilité du zooplancton et l'hétérogénéité environnementale sont encore imprécises dans les écosystèmes tropicaux côtiers. L'objectif de ce travail de thèse a donc été de déterminer les échelles de dépendance spatiale des patrons du zooplancton associé à un lagon récifal côtier et des processus environnementaux sous-jacents. Dans ce contexte, les intérêts de cette recherche ont été de quantifier les patrons de la variabilité du zooplancton dans l'espace, de comprendre comment ces patrons changent avec l'échelle spatiale et de déterminer les processus physiques et biologiques responsables de ces patrons spatiaux. L'échantillonnage, effectué le long d'un transect de la côte vers le large dans le lagon du Grand-Cul-de-Sac Marin (Guadeloupe), a concerné deux classes de taille du zooplancton (190–600 µm et > 600 µm) pour lesquelles la biomasse et l'abondance ont été estimées. L'analyse multiéchelle a été utilisée pour caractériser les patrons du zooplancton aux différentes échelles spatiales (de l'échelle de l'habitat à celle du lagon tout entier) et pour identifier les processus responsables de ces structures spatiales. Cette étude a montré que la variabilité du zooplancton est un phénomène multiéchelle dont l'amplitude et la dépendance spatiale dépendent de la taille des organismes, de leur motilité et de la variable-réponse considérée (biomasse ou abondance). La biomasse et l'abondance du zooplancton varient en réponse à la distribution spatiale du phytoplancton, au comportement du zooplancton, à l'hétérogénéité de l'habitat, à l'hydrodynamique et aux évènements météorologiques. La nature et les effets de ces processus sont dépendants de l'échelle spatiale. Ce travail a montré comment le changement d'échelle spatiale met en évidence différents niveaux d'organisation de la communauté zooplanctonique en réponse à l'hétérogénéité environnementale.

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Mulvany, Dana. "Contemporary and past conditions in the Hurunui River hapua, Canterbury, New Zealand, and the potential effects of dams on this lagoon." Thesis, University of Canterbury. Geography, 2013. http://hdl.handle.net/10092/7821.

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Hapua are complex and dynamic systems, and are especially vulnerable due of their location at the end of river catchments. The Hurunui River hapua is currently under pressure from the intensification of irrigation and agriculture, and a number of dam proposals in its catchment. The purpose of this research was to investigate the current conditions in the Hurunui River hapua, how they respond to the observed range of contemporary catchment and coastal processes, and to examine of the longer-term behaviour and vulnerability of the hapua. This information was then used to make predictions on how the hapua could be impacted if dams were to be built in the catchment, or if significant changes in the catchment occur. A multidisciplinary approach was used to investigate the short-term baseline conditions, and the long-term geomorphology of the Hurunui River hapua. Water characteristics were investigated over a falling tide, in different areas of the hapua, and in different energy conditions. The short-term behaviour of the hapua was investigated using hourly images from a time-lapse camera. The long-term vulnerability over decadal time scales was analysed using aerial photographs. This study showed that the flow of the river, the shape of the hapua, and the position of the outlet has a major control over the characteristics of the water. The surface area, the position of the barrier, and the width of the barrier of the Hurunui River hapua have been variable historically. From this research, it is predicted that the greatest impact on the Hurunui hapua would result if there is a dam related change the shape and outlet of the hapua to a state that reduces water residence time and decreases water quality. It is also predicted that if the outlet is maintained at the northern end of the hapua, and no ponded areas are present, that there would be the least problems with water quality. The findings of this research have improved the understanding of the water characteristics and processes of the Hurunui River hapua, and how they respond to change.

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Coulthard, Sarah. "Developing a people-centred approach to the coastal management of Pulicat lake, a threatened coastal lagoon in South India." Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425344.

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Dunn, Ryan J. K. "Biogeochemical Processes of a Sub-tropical Coastal Lagoon (Coombabah Lake, Southern Moreton Bay, Australia): With Emphasis on Organic Matter and Nutrient Dynamics." Thesis, Griffith University, 2009. http://hdl.handle.net/10072/365282.

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Coombabah Lake is a sub-tropical, semi-urbanised, shallow lagoon in southern Moreton Bay (Australia), recognised nationally and internationally as an important conservation and habitat zone. However, significant increases in urban development have occurred within the lagoon catchment in recent times, raising concerns over the sustainability of the lagoon ecosystem. This is typical of many estuarine environments which are ecologically and economically important waterways that often become surrounded by urban development and therefore experience degradation of water and sediment quality. The processes controlling the distribution of organic matter and nutrients in estuaries are especially important in understanding their chemical cycling. Consequently, the assessment and understanding of biogeochemical processes and other influential factors is essential for the effective management of estuaries. This study is a multi-disciplinary investigation of biological, physical, and biogeochemical processes occurring in the surface sediments and overlying waters of Coombabah Lake and the adjoining creek. The primary aim of this study was to investigate physico-chemical and biogeochemical processes occurring over various patial and temporal scales and improve the understanding of Coombabah Lake and similar shallow sub-tropical systems. Spatial variability of physico-chemical surface sediment variables and the sources and distribution of surface sediment organic matter were investigated to provide an understanding of the physico-chemical and ecological processes driving the lagoon system. Lagoon sediments were characterised by generally fine sediments with predominantly sandier sediments occurring within the northern region and muddier sediments occurring within the southern region. Although some sediment locations had elevated nutrient concentrations in comparison to adjacent lagoon sediments, nutrient concentrations within the lagoon were generally typical of Australian estuarine environments. Comprehensive analysis of biomarkers indicated that the lagoon received organic matter from a variety of autochthonous and allochthonous sources including terrestrial vascular plants (i.e. surrounding mangroves), diatoms, and benthic bacteria with the fringing mangroves potentially playing an important role in the lagoon food web. The intratidal variability of hydrological and physico-chemical variables were measured and the filterable nutrient and chlorophyll-a transport loads entering the lagoon determined. Instrumental measurements and hourly water collections provided the first account of intratidal variability within the system and indicated the lagoon and adjoining creek was characterised by a mixed tidal regime with cyclic and temporal variations in physico-chemical variables, suspended solids, and chl-a concentrations. Both dissolved oxygen and turbidity values exceeded regulatory guideline values for the region. Nutrient concentrations were typical of local and Australian estuarine environments and exceeded regulatory guideline values for the region. Nutrients sourced externally from the Coombabah Lake-Creek system resulted in increased transportation rates during flood events indicating a potential for increased nutrient loadings and enrichment within the lagoon and associated wetland environment...
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Engineering
Science, Environment, Engineering and Technology
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16

Fifield, Michael John. "Morphology, Dynamics and Hazard Management of the New River Lagoon, Westland, New Zealand." Thesis, University of Canterbury. Geography, 2012. http://hdl.handle.net/10092/7232.

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Coastal lagoon systems are complex and dynamic environments that respond rapidly to the changes of fluvial, marine, climatic and anthropogenic influences. The purpose of this research was to investigate the morphology and dynamics of the New River Lagoon before and after the implementation of engineering outlet management using a methodological framework to analyse active process environments. This information was then used to determine the functional effectiveness of engineering management at reducing the risk of flooding and erosion to the local community and imposing minimal impacts on the environmental integrity of the lagoon system. This investigation used a multidisciplinary approach to investigate the morphology and dynamics of the New River Lagoon in relation to active process environments. Outlet dynamics, lagoon channel structure and adjacent shoreline stability were assessed over a decadal timescale prior to engineering management by analysing temporal aerial photographs. Following engineering management, the hydrology of the lagoon was investigated, along with the relationship between morphological changes to the artificial lagoon outlet and changes in lagoon hydrology, local wave climate and local precipitation levels. Water depth, conductivity and temperature records were used to explain lagoon hydrology and Global Navigation Satellite Surveying (GNSS) and weekly oblique photographs were used to explain and document changes in outlet morphology. Wave and rainfall data were used to explain the balances between marine and fluvial environments and their affects on outlet dynamics. Significant changes in lagoon morphology and dynamics were observed at the New River Lagoon between pre- and post-management periods, with the former considered more stable in terms of outlet migration patterns and hydrodynamics. The lagoon outlet prior to engineering management showed morphological characteristics similar to hapua-type systems, migrating along the coastline and forming shore-parallel outlet channels in response to the dominance of a strong longshore drift of sediment. Current outlet dynamics are restricted by artificial outlet management and typically cycle intermittently between open/closed phases in response to variable levels of rainfall and marine sediment supply; characteristics similar to Intermittently Open/Closed Lagoons (ICOLs) found in areas of Australia and South Africa. Hydrologically, the lagoon is considered to be located on a continuum between hapua and estuaries during pre- and post-management periods due to intermittent tidal influences. However, artificial outlet management has significantly increased the frequency and duration of tidal exchange, which now classifies the New River lagoon closer to an estuarine environment. The artificial lagoon outlet and associated breakwater were effective at flushing high flows of water during the study period. However, the outlet was prone to blockage and migration; two morphological states capable of causing flooding. Currently, the greatest risks to flooding at the lagoon are flash floods, following dry periods where marine sediment has established a solid barrier across the outlet, during which water levels are already elevated. Increases in tidal influences, lower lagoon water levels and an increase in lagoon salinity are a direct result of engineering management intervention. An increase in freshwater flushing through the lagoon outlet and deepened of the outlet channel to below sea level, allows for pronounced tidal influences during outlet opening. Restriction of the lagoon outlet from forming a natural migration outlet channel in the direction of littoral drift has meant the outlet is most often oriented perpendicular to the sea, as appose to at an angle away from the direction of incoming waves and currents, further increasing tidal influences. In order to make sustainable management decisions, future management of the lagoon system must weight-up the effects of a high energy coastline to the integrity of the engineering structure, the impact of the structure on the lagoons environmental integrity and the outlets ability to become unstable and cause a flood risk. The findings of this research have improved the understanding of the New River Lagoon system, and its response to engineering management intervention, while adding to the understanding of river-mouth lagoon systems both nationally and internationally.

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17

Currie-Alder, Bruce Adam Barry. "Collaborative management of the Mexican coast public participation and the oil industry in the Terminos Lagoon protected area /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/mq61546.pdf.

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18

Samarasekara, Vidhisha Nayanthara. "Local perceptions of environmental change in a tropical coastal wetland : the case of Koggala Lagoon, Galle, Sri Lanka." Thesis, SOAS, University of London, 1996. http://eprints.soas.ac.uk/29438/.

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Tropical coastal wetlands are under ecological stress, most notably due to accelerated development activities associated with these areas. Consequently, natural resource depletion and environmental problems in the coastal sector are increasingly serious issues, particularly in South and South East Asia, and have significant implications for their traditional resource-user groups. This thesis is primarily based on a detailed investigation of the inter-relationships between environmental change and local perception of change at Koggala, Galle, southern Sri Lanka, where six sample Divisions bordering Koggala Lagoon were selected for in-depth study. Multi-disciplinary techniques from both the natural and the social sciences were employed, focusing on the environmental changes involved and on the perceptions of these changes by local fishing and farming communities. Particular attention was paid to changes in agriculture, to the reconfiguration of a coastal sand bar, and to the development of a Free Trade Zone. Participatory techniques involved the experimental use of group discussions. Visits were made to Malaysia and Thailand for comparative study purposes. Results show that the fringing mangrove complex is currently threatened by a number of factors and that sand mining close to the lagoon outlet has severely disrupted water levels in the lagoon and ultimately rice-farming systems. The fishing community further perceives significant declines in their fish catch, attributing this to the loss of fishery nursery sites and to the seepage of agro-chemicals, some belonging to highly toxic groups, into the lagoon. It is clear that local communities display a high degree of awareness of environmental change, as well as of the causes of this change. Such understanding can be used to develop local-level adaptive planning for wetland management. The use of discussion groups is seen as a novel approach to such wetland management programmes in the tropics.

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19

Marques, Alexandra Jorge Silva. "Distribution of the plankton community in the Ria Formosa, a coastal lagoon in south eastern Portugal." Thesis, Bangor University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429848.

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20

Bellafiore, Debora <1981&gt. "Study of the circulation processes in the northern Adriatic sea - coastal area and Venice lagoon inlets." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/2104/.

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This work is a detailed study of hydrodynamic processes in a defined area, the littoral in front of the Venice Lagoon and its inlets, which are complex morphological areas of interconnection. A finite element hydrodynamic model of the Venice Lagoon and the Adriatic Sea has been developed in order to study the coastal current patterns and the exchanges at the inlets of the Venice Lagoon. This is the first work in this area that tries to model the interaction dynamics, running together a model for the lagoon and the Adriatic Sea. First the barotropic processes near the inlets of the Venice Lagoon have been studied. Data from more than ten tide gauges displaced in the Adriatic Sea have been used in the calibration of the simulated water levels. To validate the model results, empirical flux data measured by ADCP probes installed inside the inlets of Lido and Malamocco have been used and the exchanges through the three inlets of the Venice Lagoon have been analyzed. The comparison between modelled and measured fluxes at the inlets outlined the efficiency of the model to reproduce both tide and wind induced water exchanges between the sea and the lagoon. As a second step, also small scale processes around the inlets that connect the Venice lagoon with the Northern Adriatic Sea have been investigated by means of 3D simulations. Maps of vorticity have been produced, considering the influence of tidal flows and wind stress in the area. A sensitivity analysis has been carried out to define the importance of the advection and of the baroclinic pressure gradients in the development of vortical processes seen along the littoral close to the inlets. Finally a comparison with real data measurements, surface velocity data from HF Radar near the Venice inlets, has been performed, which allows for a better understanding of the processes and their seasonal dynamics. The results outline the predominance of wind and tidal forcing in the coastal area. Wind forcing acts mainly on the mean coastal current inducing its detachment offshore during Sirocco events and an increase of littoral currents during Bora events. The Bora action is more homogeneous on the whole coastal area whereas the Sirocco strengthens its impact in the South, near Chioggia inlet. Tidal forcing at the inlets is mainly barotropic. The sensitivity analysis shows how advection is the main physical process responsible for the persistent vortical structures present along the littoral between the Venice Lagoon inlets. The comparison with measurements from HF Radar not only permitted a validation the model results, but also a description of different patterns in specific periods of the year. The success of the 2D and the 3D simulations on the reproduction both of the SSE, inside and outside the Venice Lagoon, of the tidal flow, through the lagoon inlets, and of the small scale phenomena, occurring along the littoral, indicates that the finite element approach is the most suitable tool for the investigation of coastal processes. For the first time, as shown by the flux modeling, the physical processes that drive the interaction between the two basins were reproduced.

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21

Matsumoto, Dan. "Characteristics of the 2004 Indian Ocean tsunami deposits formed upon a lagoon floor and coastal lowland." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/136900.

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22

Hadj, Amor Raja. "Evaluation des impacts anthropiques de l'écosystème lagunaire d'El Melah de Slimane (Tunisie) par la méthode d'analyse du cycle de vie." Université Louis Pasteur (Strasbourg) (1971-2008), 2008. https://publication-theses.unistra.fr/restreint/theses_doctorat/2008/HADJ_AMOR_Raja_2008.pdf.

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23

Lundmark, Kim. "The spatial variability of salinity and water flux estimates in Gialova Lagoon, Greece." Thesis, Stockholms universitet, Institutionen för naturgeografi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-161341.

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Lagoons are coastal waterbodies which are sensitive to meteorological and hydrological changes. This study focused on the spatial distribution of salinity in Gialova lagoon, Greece. The area in which the lagoon is located is under pressure from agriculture and truism in the area. Besides that, the lagoon is an important stop for migratory birds as well as the home for rare species. To investigate how salinity is distributed in the lagoon a salinity gradient was produced. Also, an attempt was made to model the salt and fresh water fluxes in the lagoon using a mass balance approach. The water fluxes are either from fresh water sources or influx of saline water from the sea. Manual electric conductivity measurements were taken during a field campaign to the lagoon. Time series data used in the model was obtained from stations in the lagoon and the surroundings. An investigation in how the lagoon measurement station differ in salinity was also performed in this study. Results from the gradient map and manual measurements show that the water in the lagoon is the freshest in the North-Eastern parts and the most saline to the South-West. The modelled water fluxes show an inverse relationship from each other. High fresh water fluxes correspond to precipitation events, lower salinity concentration. Whereas high salt water fluxes correspond to high salinity concentration and lowered precipitation. The stations concentrated to the middle lagoon show corresponding values in salinity whereas the station to the South-West differs. The canal surrounding the lagoon shows interactions since measurements show that the water is brackish. A longer time series could provide patterns in water fluxes over time. Trying to find the portions of terrestrial groundwater and surface water, and further investigation of the regional aquifer could provide new information to develop this model. The region is expected to experience water stress which makes further studies and monitoring important.

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24

Haghani, Safiyeh. "Evolution of the Sefidrud Delta (south west Caspian Sea) during the last millennium." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/13779.

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The Sefidrud has developed a large delta in the south west of the Caspian Sea. Its delta is characterized by rapid sedimentation rate (20 mm/yr) in the delta plain and low sedimentation rate (1.67 mm/yr) in a very steep delta front. Sefidrud Delta evolution depends upon sediment supply by river and longshore current under rapid Caspian Sea Level (CSL) fluctuation and tectonic setting at the point of entry to the basin. The tectonic setting caused a very steep slope in the delta front. Sediment supply is variable and affected by river avulsion and dam construction. The CSL has undergone significant changes during the last millennium. Therefore, the Sefidrud Delta evolution during the last millennium is explained based on CSL fluctuations. This fluctuation has major impacts not only on coastal lagoons, but also more inland in wetlands when the CSL rose up to at least -21.44 m (i.e. >6 m above the present water level) during the early Little Ice Age. Although previous studies in the southern coast of the Caspian Sea have detected a high-stand during the Little Ice Age period, this study presents the first evidence that this high-stand reached so far inland and at such a high altitude. This study also examines the interdependence of different factors in the evolution of coastal lagoons as a part of delta evolution. Dam flushing operations and rapid sea–level rise (~3 m between 1977 and 1995) have accelerated the infilling of the coastal lagoon system. This rapid infilling (31 mm/yr) makes the whole system more prone to sediment encroachment in the short term. Because the lagoons are short-lived and have dynamic evolution, the impact of the Anthropocene is also visible in the delta evolution.

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Borrelli, Mark. "Sediment transport in a dynamic, tidally-influenced coastal embayment exemplified by Pleasant Bay and Chatham Harbor, Cape Cod, Massachusetts." View online ; access limited to URI, 2008. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3328718.

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26

LeBlanc, Allison Renee. "A 1000-year sedimentary record of hurricane, fire, and vegetation history from a coastal lagoon in southwestern Dominican Republic." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/76775.

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Our knowledge of whether hurricanes cause lasting changes in forest composition and the patterns and role of fire in Caribbean dry forests are lacking. This project combines paleoecological and paleotempestological methods to document the disturbance and environmental history of the last 1000 yrs at Laguna Alejandro, situated in the lowland dry forests of arid SW Dominican Republic. I analyzed multiple proxy data sources of a 160 cm coastal lagoon sediment profile. High-resolution (1 cm) sampling for loss-on-ignition and magnetic susceptibility indicated multiple erosion and hurricane events, including a hurricane ~996 cal YBP, and several erosion events and hurricanes between ~321 cal YBP and present day. Pollen analysis documented 32 plant families with most levels dominated by pollen of Fabaceae (legumes), the Urticales order, and Cyperaceae (sedges), though families of upland and montane vegetation are also present ~510-996 cal YBP. All pollen slides contained microscopic charcoal indicating the occurrence of regional or extra-local fires over the last ~1000 yrs. Local fires, as indicated by macroscopic charcoal, occurred before ~434 cal YBP and may be tied to hurricanes, increased moisture in the region (thereby increased fuel and ignition chances), or prehistoric human activities. Pollen spectra representing periods before and after disturbance events were similar and may support the idea of forest resilience, but more samples are needed. Multiple erosion events between ~294 cal YBP and present may be tied to hurricanes or tropical storms and increasing late-Holocene aridity in the region as documented by several studies from the Caribbean.
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Manzolli, Rogério Portantiolo. "Gênese e evolução do Sistema Laguna-Barreira da Feitoria." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/150875.

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O sistema laguna-barreira da Feitoria localizado na margem oeste da célula Sul da laguna dos Patos – Rio Grande do Sul, Brasil – se assemelha geomorfologicamente, em uma escala menor, a um sistema barreira oceânico e cronologicamente ao sistema Barreira IV (Villwock e Tomazelli, 1995). Com o intuito de caracterizar a morfologia e a estratigrafia deste sistema deposicional laguna-barreira foi estudada a geologia de superfície e de subsuperfície. As características geológicas de superfície foram obtidas através da análise de aerofotografias e de imagens de satélite; de levantamentos topográficos e das análises geocronológicas por Luminescência Oticamente Estimulada em sedimentos superficiais. A geologia de subsuperfície foi caraterizada a partir da análise de perfis geofísicos registrados com sísmica rasa e de seções de georradar; junto foram integradas as análises granulométricas, palinológicas e geocronológicas (radioisótopos de 14C) coletadas em testemunhos de sondagem. Através da compilação crítica dos resultados obtidos, esta Tese apresenta evidências de que a gênese da barreira da Feitoria e da laguna na sua retaguarda, está correlacionada a topografia antecedente, marcada pela existência de um alto topográfico remanescente entre os paleovales fluviais dos rios Turuçu e Corrientes, onde este alto serviu de substrato para o início do desenvolvimento desta barreira. Também, é evidenciado que a evolução geomorfológica da barreira da Feitoria (orientação, truncamentos e tipologia dos cordões litorâneos), subdividida em nove fases de deposição, ocorreu associada as variações relativas do nível do mar a partir do Holoceno médio (8.000 anos A.P.). Observa-se também que foi influenciada diretamente pelas flutuações de alta frequência do nível de base da laguna dos Patos, causadas pela interação de três fatores: variabilidade no volume de precipitação na área da bacia de drenagem; marés meteorológicas causadas pelo vento; e alterações geomorfológicas na desembocadura da laguna dos Patos. O início da progradação dos cordões litorâneos na barreira da Feitoria ocorreu, aproximadamente, a 7.200 anos A.P., cronocorrelato ao período em que o nível relativo médio do mar ultrapassou o nível atual. A cota altimétrica da 1° crista destes cordões litorâneos encontra-se a 4,2 m acima do nível do mar atual, evidenciando a sobre-elevação do nível de base lagunar para a formação dos mesmos. A ilha da Feitoria, porção sul da barreira, teve sua formação, aproximadamente, a 5.000 anos A.P. associada ao rebaixamento do nível do mar e, consequentemente, ao afloramento do paleoalto topográfico da Feitoria. A partir deste período o controle sobre a morfologia e a orientação dos cordões litorâneos passa a ter uma maior influência associada as modificações na geomorfologia da desembocadura da laguna dos Patos (alta frequência). No entanto, as variações do nível de base lagunar (volume de precipitação e marés meteorológicas) de mais alta frequência são as responsáveis pela gênese das cristas dos cordões litorâneos. A deposição de sedimentos finos na área da laguna Pequena (retaguarda) começa antecedentemente a 7.730 anos A.P. com um aumento de influência marinha, próximo a esta idade, passando por um curto período com menor influência, retornando a aumentar a entrada de água salgada no interior da laguna dos Patos próximo a 7.000 anos A.P. A partir deste período, apesar das oscilações de alta frequência, passa a ter uma tendência de diminuir gradativamente a influência marinha no interior das lagunas dos Patos e Pequena. Esta diminuição da influência marinha pode ser correlacionada ao estreitamento do canal de ligação entre a laguna dos Patos e o oceano, assim como, o desenvolvimento da barreira da Feitoria diminuiu a comunicação entre a laguna Pequena e a laguna dos Patos.
The lagoon-barrier system of the Feitoria located on the western margin of the southern cell of the Patos lagoon - Rio Grande do Sul, Brazil - resembles geomorphologically, on a smaller scale, to the barrier system oceanic and chronologically to the Barrier IV system (Villwock e Tomazelli, 1995). In order to characterize the morphology and stratigraphy of this depositional lagoon-barrier system, the surface and subsurface geology were studied. The surface geological characteristics were obtained from the analysis of aerial photographs and satellite images; surveying and geochronological analyzes Optically Stimulated Luminescence of surface sediments. The subsurface geology was characterized by the analysis of geophysical profiles recorded with shallow and georadar seismic; and granulometric, palynological and geochronological analyzes (14C radioisotopes) of sedimentary records. This thesis presents evidences that the genesis of the Feitoria barrier and the Pequena lagoon is correlated with the previous topography, marked by the existence of a high topographic remnant among the fluvial paleovales of the Turuçu and Corrientes rivers, where this high served as a substrate for the beginning of the development of this barrier. Also, it is evidenced that the geomorphological evolution of the Feitoria barrier (orientation, truncations and typology of beach ridges), subdivided into 9 phases of deposition, was associated with sea level variations from the average Holocene (8,000 years Before the Present) and was also influenced directly by the high frequency fluctuations of the basal level of the Patos lagoon, caused by the interaction of three factors: variability in the volume of precipitation in the area of the drainage basin; wind tides; And geomorphological changes at the mouth of the Patos lagoon. The beginning of the development of the coastal strands in the Feitoria barrier occurred approximately 7,200 years B.P., chronologically during the period in which the average relative sea level exceeded the current level. The crest of the first ridge of these coastal strands is 4.2 m above current sea level, evidencing the over-elevation of the lagoon base level for their formation. The island of Feitoria, southern portion of the barrier, began approximately 5,000 years BP associated with the decline of sea level and the outcropping of the topographic paleoalto of Feitoria. From this period, the control over the morphology and orientation of the coastal strands will have a greater influence associated with the changes in the geomorphology of the mouth of the Patos lagoon (high frequency). However, variations in lagoon base level (volume of precipitation and wind tides) the highest frequency are responsible for the genesis of coastal beach ridges. The deposition of fine sediments in the Pequena lagoon area starts before 7,730 years BP with an increase of marine influence, near this age (palinological records), passing for a short period with less influence, returning to increase the entrance of salt water inside Patos lagoon, near to 7,000 years BP. From this period, despite the high frequency oscillations, there is a tendency gradually decrease the marine influence inside the lagoons Patos and Pequena. This decrease in the marine influence can be correlated to the narrowing of the channel connecting the Patos lagoon to the ocean, as well as the development of the Feitoria barrier, reducing the communication between the lagoons Pequena and Patos.

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Dias, Cláudia Pessoa. "Biology, ecology, population dynamics and distribution of metals in Sepia officinalis on a typical estuarine coastal lagoon - Ria de Aveiro." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13611.

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Doutoramento em Biologia
The common cuttlefish, Sepia officinalis, is a necto-benthic cephalopod that can live in coastal ecosystems, with high influence of anthropogenic pressures and thus be vulnerable to exposure to various types of contaminants. The cuttlefish is a species of great importance to the local economy of Aveiro, considering the global data of catches of this species in the Ria de Aveiro. However, studies on this species in Ria de Aveiro are scarce, so the present study aims to fill this information gap about the cuttlefish in the Ria de Aveiro. The cuttlefish enters Ria de Aveiro in the spring and summer to reproduce, returning to deeper waters in the winter. In terms of abundance, the eastern and center regions of the lagoon, closer to the sea, showed the highest values of abundance, while the northern and southern regions of the main channel had the lowest abundance. This fact may be related to abiotic factors, as well as depth, salinity and temperature. In the most southern point of the Ria de Aveiro (Areão) no cuttlefish was caught. This site had the lowest values of salinity and depth. The cuttlefish has an allometric the females being heavier than males to mantle lengths greater than 82.4 mm. Males reach sexual maturity first than females. In Ria de Aveiro in a generation of parents was found. The cuttlefish, presents itself as opportunistic predators, consuming a wide variety of prey from different taxa. The diet was similar in different sampling locations observing significant differences for the seasons. S. officinalis was captured at 10 sites in the Ria de Aveiro with different anthropogenic sources of contamination. Thus, levels of metals analyzed were similar at all sampling sites, with the exception of a restricted area, Laranjo, which showed higher values. The cuttlefish has the ability to accumulate metals in your body. The levels of Fe, Zn, Cu, Cd, Pb and Hg found in the digestive gland and mantle reflect a differential accumulation of metals in the tissues. This accumulation is related to the type and function of tissue analyzed and the type of metal analysis (essential and non-essential). The metal concentrations in the digestive gland are higher than in the mantle, with the exception of mercury. This may be due to the high affinity of the mantle for the incorporation of methylmercury (MeHg), the most abundant form of mercury. The accumulation of metals can vary over a lifetime, depending on the metal. The concentrations of Zn, Cd and Hg increases throughout life, while Pb decreases and essential metals such as Fe and Cu remain constant. The data collected suggest that the cuttlefish (Sepia officinalis) can be used as a bioindicator of environmental contamination for some metals.
O choco comum, Sepia officinalis, é um cefalópode necto-bentónico que pode viver em ecossistemas de águas costeiras, com elevada influência de pressões antropogénicas e assim, estar vulnerável à exposição por vários contaminantes. O choco é uma espécie de grande importância para a economia local de Aveiro, considerando os dados globais de capturas desta espécie para a Ria de Aveiro. No entanto, os estudos acerca desta espécie na Ria de Aveiro são escassos, desta forma o presente estudo pretende preencher esta lacuna de informação sobre o choco na Ria de Aveiro. O choco entra para a Ria na primavera e no verão para reprodução, e volta para águas mais profundas no inverno. Em termos de abundância, as zonas, este e central da ria, a mais próxima da embocadura com o mar, apresentaram os valores de abundância mais elevados, sendo as regiões mais a norte e a sul dos principais canais, as de abundância mais baixa. Este fato pode estar relacionado com fatores abióticos, como a profundidade, a salinidade e a temperatura. No ponto mais a sul da Ria de Aveiro (Areão) nunca foram capturados chocos, tendo este local apresentado os valores mais baixos de salinidade e profundidade. O choco apresenta um crescimento alométrico, sendo as fêmeas mais pesadas que os machos, para comprimentos do manto superiores a 82.4 mm. Os machos atingem a maturação sexual primeiro que as fêmeas. Na Ria de Aveiro apenas uma geração de progenitores foi encontrada. O choco apresenta-se como predador oportunista, consumindo uma grande diversidade de presas de diferentes grupos taxonómicos. A dieta mostrou-se semelhante nos diferentes locais de amostragem observando-se diferenças significativas para as estações do ano. S. officinalis foi capturada em 10 locais da Ria de Aveiro com contaminação de diferentes origens antropogénicas. Assim, os níveis de metais analisados apresentaram-se semelhantes em todos os locais de amostragem, com a exceção de uma área restricta, o largo do Laranjo, que apresentou valores mais elevados. O choco possui a capacidade de acumular metais no seu organismo. Os níveis de Fe, Zn, Cu, Cd, Pb and Hg encontrados no manto e na glândula digestiva refletem uma acumulação diferencial de metais nos tecidos. Esta acumulação está relacionada com o tipo e função do tecido analisado e com o tipo de metal analisado (essencial e não essencial). As concentrações dos metais na glândula digestiva são mais elevadas que no manto, com exceção do mercúrio. Este fato pode dever-se à grande afinidade do manto para a incorporação de Metilmercúrio (MeHg), a mais abundante forma de mercúrio. A acumulação de metais pode variar ao longo da vida, dependendo do metal. As concentrações de Zn, Cd and Hg aumentam ao longo da vida, o Pb diminui e os metais essenciais como o Fe e Cu permanecem constantes. Os dados recolhidos sugerem que o choco (Sepia officinalis) possa ser usado como bioindicador de contaminação ambiental para alguns metais.

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Seiler, Lilian Marques Nogueira. "Modelagem numérica da Lagoa dos Patos: variação espacial e temporal da qualidade da água." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/21/21136/tde-23042015-103406/.

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Este trabalho aborda a influência da hidrodinâmica da Lagoa dos Patos (RS) no comportamento de variáveis indicadoras da qualidade da água, como o material em suspensão, o oxigênio dissolvido, os nutrientes inorgânicos dissolvidos e a clorofila-a. Adicionalmente, o trabalho apresenta uma avaliação do efeito do lançamento de efluentes na magnitude das concentrações destas variáveis e nas suas inter-relações. Para o desenvolvimento deste estudo aplicou-se o modelo numérico MOHID 2D, utilizado com êxito na gestão ambiental de regiões costeiras. Os resultados indicam que a Lagoa dos Patos é um corpo lagunar heterogêneo no qual sua hidrodinâmica é regida principalmente pela atuação dos ventos e da vazão fluvial. Esses fatores influenciam diretamente o comportamento das variáveis estudadas. A presença de efluentes altera significativamente a magnitude das concentrações dos nutrientes e da clorofila-a no ambiente, principalmente nas regiões próximas aos locais de lançamento. A modelagem numérica é uma importante ferramenta para a gestão ambiental de sistemas dinâmicos e que variáveis ecológicas são condicionadas pelas suas inter-relações e pela circulação do sistema.
This work assesses the influence of Patos Lagoon- RS hydrodynamics in the behavior of water quality indicator variables as like suspended material, dissolved oxygen, dissolved inorganic nutrients and chlorophyll-a. Also gives an assessment of the effect of effluent discharge in the magnitude of the concentrations of these variables and in their interrelationships. To develop this study we applied the numerical model MOHID 2D, successfully applied in environmental management of coastal areas. The results indicate that Patos Lagoon is a heterogeneous system in which its hydrodynamic is governed mainly by the action of wind and river flow, which directly influence the behavior of water quality variables. Furthermore, the presence of effluent significantly changes the magnitude of the nutrients and chlorophyll-a concentration, particularly in areas close to the sewage launch sites. We concluded that the numerical modeling is an important tool for the dynamics systems management and that ecological variables are not only conditioned by their interrelations, but also by system circulation.

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Silva, Raquel Lemos da. "EvoluÃÃo morfodinÃmica e hidrolÃgica direcionada ao manejo de lagoas costeiras tropicais. Estudo de caso: lagoa das almÃcegas, Paraipaba - Trairi/Ce." Universidade Federal do CearÃ, 2007. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1687.

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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
A lagoa costeira, AlmÃcegas, estÃ localizada no litoral Oeste do Estado do CearÃ na divisa dos municÃpios de Trairi e Paraipaba. O principal objetivo deste trabalho foi avaliar a evoluÃÃo os processos controladores da morfologia e hidrologia da Lagoa das AlmÃcegas visando gerar informaÃÃes Ãteis ao uso e gestÃo desse recurso hÃdrico costeiro. A origem da lagoa das AlmÃcegas estÃ subordinada ao comportamento climÃtico-natural da Ãrea, bastante influenciado pela dinÃmica litorÃnea. Com a gÃnese relacionada aos processos transgressivos e regressivos do mar, e barramento do riacho pelo sistema de dunas (transporte eÃlico) e processos associado (descarga fluvial), sendo posteriormente com a construÃÃo da barragem. A metodologia utilizada para realizaÃÃo desta pesquisa baseia-se na compreensÃo da organizaÃÃo da natureza dentro do espaÃo, e a relaÃÃo que ocorre entre seus componentes. Para tanto foram realizadas analises dos parÃmetros fÃsicos e quÃmicos da Ãgua: temperatura, condutividade elÃtrica, turbidez, pH e transparÃncia. Ademais, foram coletadas amostras de subsuperfÃcie e fundo para a investigaÃÃo de material em suspensÃo. TambÃm, realizou-se a caracterizaÃÃo sedimentolÃgica, analise de matÃria orgÃnica e metaisâtraÃo (cobre, cÃdmio e zinco) no sedimento, e o estudo morfomÃtrico e levantamento batimÃtrico da lagoa. Os resultados demonstram que o sistema estudado apresentou variaÃÃo sazonal relacionada aos dois perÃodos hidrolÃgicos distintos. O perÃodo chuvoso se caracterizou por precipitaÃÃes mais intensas e menor insolaÃÃo, enquanto que o seco apresentou maior insolaÃÃo e maiores velocidades dos ventos, trazendo conseqÃÃncias diretas sobre o nÃvel dâÃgua da lagoa. A coluna dâÃgua apresentou estratificaÃÃo (tÃrmica) significativa devido principalmente Ã profundidade do sistema, Ã atuaÃÃo dos ventos e transparÃncia da coluna dâÃgua. A composiÃÃo granulomÃtrica dos sedimentos de fundo da Lagoa das AlmÃcegas resultaram em seis classes principais: areia com cascalho esparso (43,8 %), areia (25%), areia fina (6,3%), areia siltosa (6,3%), areia lamosa (6,3%), silte (6,3%) e silte arenoso (6,3%). Observa-se que as fraÃÃes grossas do sedimento, maiores que 0,063 mm, ocorrem na grande maioria das amostras, o que pode estÃ relacionado ao processo de assoreamento. A distribuiÃÃo da matÃria orgÃnica indica os diferentes graus de aeraÃÃo das diversas Ãreas do ambiente de sedimentaÃÃo. Quanto Ã morfologia a lagoa apresentando uma Ãrea de 1,3 km2, perÃmetro de 9,935 Km, largura mÃxima de 684 m e comprimento de 3,5 km, volume de 6.688.000 mÂ, profundidade mÃxima de 5,85 m, profundidade mÃdia de 2,55m. A relevÃncia do volume classifica este reservatÃrio como de capacidade de armazenamento satisfatÃrio. Em termos de ocupaÃÃo, a lagoa encontra-se com baixa ocupaÃÃo imobiliÃria, devido principalmente a pouca especulaÃÃo. Mas, as ocupaÃÃes que jÃ ocorrem na regiÃo ultrapassam os limites impostos pela lei (Ãreas de PreservaÃÃo Permanente), jÃ a ocupaÃÃo associada Ã retirada da cobertura vegetal Ã possÃvel de ser vista, e este problema pode gerar uma instabilidade das margens e conseqÃente alteraÃÃo das caracterÃsticas morfomÃtricas e fÃsicoquÃmicas da lagoa, podendo ocasionar impactos negativos, como aumento do escoamento superficial, erosÃo das margens, maior aporte de sedimentos na lagoa, assoreamento, diminuiÃÃo do volume de Ãgua, e maior concentraÃÃo de poluentes na lagoa, podendo vir a comprometer tambÃm a vida da populaÃÃo local.
The coastal lagoon, AlmÃcegas, are located in the coastal West of the State of the CearÃ in the verge of the cities of Trairi and Paraipaba. The main objective of this work was to evaluate the evolution the controlling processes of the morphology and hidrology of the Lagoon of the AlmÃcegas being aimed at to generate useful information to the use and management of this coastal hÃdrico resource. The origin of the lagoon of the AlmÃcegas is subordinated to the climatic-natural behavior of the area, sufficiently influenced for the littoral dynamics. With genesis related to the transgression and regression processes of the sea, and slide bars of the extended river for the dune system (aeolian transport) and processes associated (fluvial discharge), being later with the construction of the barrage. The methodology used for accomplishment of this research is based inside on the understanding of the organization of the nature of the space, and the relation that occurs between its components. For they had been in such a way carried through you analyze of the physical and chemical parameters of the water: temperature, electric condutividade, turbidez, pH and transparency. Furthermore, had been collected samples of deep subsurface and for the inquiry of material in suspension. Also, it was become fullfilled sedimentation characterization, analyzes of organic substance and metal-traces (it has covered, cadmium and zinc) in the sediment, and the morfomÃtrico study and batimÃtrico survey of the lagoon. The results demonstrate that the studied system presented related sazonal variation to the two distinct hidrolÃgicos periods. The rainy period if characterized for more intense precipitations and lesser insolation, whereas the dry one presented greater insolation and greaters speeds of the winds, bringing direct consequences on the water level of the lagoon. The water column presented stratification (thermal) significant had mainly to the depth of the system, to the performance of the winds and transparency of the water column. The grain sized composition of the sediments of deep of the Lagoon of the AlmÃcegas had resulted in six main classrooms: slightly gravelly sand (43.8%), sand (25%), fine sand (6.3%), muddy sand (6.3%), slightly gravelly muddy sand (6.3%), silt (6.3%) and sandy silt (6.3%). It is observed that the thick fractions of the sediment, greaters that 0,063mm, occur in the great majority of the samples, what it can is related to the silting. The distribution of the organic substance indicates the different degrees of aeration of the diverse areas of the sedimentation environment. How much to the morphology the lagoon presenting an area of 1,3km2, perimeter of 9,935Km, maximum width of 684m and length of 3,5km, Volume of 6.688.000m Â, maximum depth of 5,85m, average depth of 2,55m. The relevance of the volume classifies this reservoir as of capacity of satisfactory storage. In occupation terms, the lagoon meets with low real estate occupation, had mainly to little speculation. But, the occupations that already occur in the region exceed the limits taxes for the law (Areas of Permanent Preservation) already the occupation associated with the withdrawal of the vegetal covering are possible of being seen, and this problem can generate an instability of the edges and consequence the alteration of the morfomÃtricas characteristics and physicistchemistries of the lagoon, being able to cause negative impacts, as increase of the superficial draining, erosion of the edges, greater arrives in port of sediments in the lagoon, assoreamento, reduction of the volume of water, and greater concentration of pollutants in the lagoon, being able to come also compromising the life of the population place.

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Mello, Tatiana Baptista Martinez. "Caracterização Biogeoquímica da Lagoa de Araruama, RJ." Niterói, 2017. https://app.uff.br/riuff/handle/1/3997.

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Fundação de Amparo a Pesquisa do Rio de Janeiro
Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ
A lagoa de Araruama é o maior sistema lagunar hipersalino do Estado do Rio de Janeiro, e por se localizar em uma região de alta procura turística, recebeu durante as últimas décadas grandes quantidades de efluentes domésticos. Em julho de 2005, suas águas claras e oligotróficas tornaram-se escuras. Desta maneira, o presente trabalho teve como objetivo avaliar o estado trófico atual relacionando as características biogeoquímicas de diferentes pontos de coleta com as recentes alterações do sistema através de parâmetros físico-químicos, metabolismo, nutrientes orgânicos e inorgânicos, clorofila a e através da composição elementar e isotópica dos sedimentos superficiais. Para tanto foram realizadas duas abordagens para as campanhas: a primeira, em 11 estações de coleta na margem, foram realizadas nos meses de setembro, outubro e dezembro de 2005, abrangendo extremos no balanço evapo-precipitação com maiores valores no mês de outubro e valores negativos em dezembro; e a segunda em 12 estações de coleta na região limnética da lagoa (em janeiro de 2006). A maioria dos parâmetros analisados em cada estação de coleta não apresentou diferença significativa entre os meses de setembro, outubro e dezembro de 2005 (ANOVA). Entre os pontos coletados diferenças significativas foram encontradas para as estações segundo alguns parâmetros (ex. COD, POT e Chl a) separando os pontos localizados próximos as desembocaduras dos rios, dos pontos na margem da Lagoa e daqueles situados no canal de contato com o mar. Elevados valores das diferentes espécies de carbono foram encontrados principalmente nas estações centrais (CID=95±31, COD=24±8 e COP= 7,6±1,6 mg.L-1). As estações localizadas nas margens apresentaram concentrações similares, sendo destacadas as entradas de NIT (37±67M) e PO4-3 (5,5±7,3M) principalmente pelos rios R. Maturama e R. Mossoró, durante os meses mais chuvosos. Nestes pontos, maiores concentrações de CO2-excesso caracterizaram atividades metabólicas heterotróficas, enquanto que nas estações localizadas na margem foi encontrado um balanço entre autotrofia e heterotrofia. Já o metabolismo avaliado no centro da lagoa foi caracterizado como autotrófico, devido à elevada produtividade primária liquida. No entanto, os elevados teores de carbono e clorofila sustentados pela entrada de nutrientes e o elevado tempo de renovação de suas águas (T50% = 84 dias) podem levar este sistema apresentar sucessivas crises distróficas. Devido às mudanças antrópicas ocorridas nas ultimas décadas no entorno da lagoa, foi evidenciada intensa entrada de matéria orgânica no sistema, modificando seu estado trófico de oligotrófico para hipertrófico (C/N/PMARGEM = 603/37/1 e C/N/PCENTRO = 941/57/1). Estas mudanças aumentaram a ciclagem nos sedimentos, impulsionando a produtividade primária em toda a coluna d’água e diminuindo, devido a menor penetração da luz, a importância da produtividade bentônica. Com isto, a lagoa de Araruama apresentou aumento nos estoques das diferentes espécies de carbono nos compartimentos da coluna d’água e dos sedimentos, demonstrando uma estreita relação entre as entradas de carbono e sua ciclagem no processo de eutrofização. Os resultados gerados com este trabalho evidenciam a necessidade de futuras pesquisas que abordem o impacto da dragagem no canal sobre a variabilidade da qualidade das águas na lagoa e principalmente que quantifique os fluxos de elementos para avaliação da renovação das águas da lagoa com o mar.
The Araruama lagoon is the most hipersaline coastal lagoon of the Rio de Janeiro State and has been experienced for the last decades an intense domestic sewage load due to high tourism pressure. Since 2005 July, its clean and oligotrophic waters got dark. This work intended to evaluate the new trophic level relating recent environment changes with biogeochemistry characteristics measure through physical-chemical parameters, metabolism, nutrients, chlorophyll a and elemental and isotopic composition of the sediments. Two samples approaches were developed. The first one considered 11 sites around the lagoon at September, October and December months of 2005 year. It was considered the months with extreme values of evaporation-precipitation ratios, with positive values in October and negative values in December. The second approach considered 12 sites distributed in the limnetic region of the lagoon (2006 January). Most of the parameters analyzed in each site did not presented significant differences among months samples (ANOVA statistic analysis). Among sites sampled, significant differences were found for some of the parameters (ex. DOC, TOP and Chl a) separating sites localized near the rivers mouths from the others shore sites and by the sites in the middle of the lagoon. Higher values of the different carbon species were found mainly at the limnetic lagoon sites (DIC=95±31, DOC=24±8 e POC= 7,6±1,6 mg.L-1). Among the lagoon shore sites we found similar concentrations highlighting the TIN (37±67M) e PO4-3 (5,5±7,3M) input from the rivers Maturama and Mossoró during the rainy months. At those rivers sites higher CO2-excess characterized heterotrophic activities. At the other shore sites the metabolism was characterized with a balance among auto and heterotrophic. On the other hand, the limnetic region of the lagoon were characterized as autotrophic due to the high primary productivity. However, high carbon and chlorophyll content supported by the rivers input and by the long water renewed (T50% = 84 dias) should carry this system to present dystrophic crisis. Due to recent human changes during recent decades around the lagoon drainage basin, it was evident a trophic level change from oligotrophic to hipertrophic (C/N/PMARGIN = 603/37/1 e C/N/PCENTER = 941/57/1). Those changes increased the sediments nutrient cycles, growing the primary productivity in the water column and decrease the benthonic productivity due to the less luminosity. Finally, the Araruama lagoon was characterized from an increase in the biogenic elements budgets of the water column and sediment compartments. It demonstrate a narrow relationship between the high organic matter input in a restricted lagoon that has already been experienced a eutrophication process. The results from this work highlight the necessity of future research to deal with the impacts of the effluent loads, the necessity of the ocean-channel drainage, the assessment of the water quality variability and mainly with an estimative of lagoon water renew measure through organic matter fluxes from the lagoon to the ocean.

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32

Iversen, David Richard. "Testing the coastal decline model with flaked stone artifacts from the San Diego region of California." Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Spring2007/d_iversen_041607.pdf.

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33

Crippa, Liziane Bertotti. "O manejo da abertura da barra influencia a comunidade de macroinvertebrados nas áreas úmidas do sul do Brasil? Um estudo de caso no Parque Nacional da Lagoa do Peixe." Universidade do Vale do Rio dos Sinos, 2011. http://www.repositorio.jesuita.org.br/handle/UNISINOS/3914.

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A Lagoa do Peixe situada no Parque Nacional da Lagoa do Peixe – sul do Brasil - tem sua conexão com o mar aberta artificialmente todos os anos no final do inverno. Entretanto, esse manejo vem sendo realizado sem avaliar os impactos da abertura da barra na biodiversidade aquática das áreas úmidas da região. As seguintes questões foram testadas nesse estudo: 1) A riqueza, a abundância e a composição de macroinvertebrados da planície de inundação da Lagoa do Peixe variam temporalmente com a abertura e fechamento da barra? 2) O padrão de variação da comunidade de macroinvertebrados varia com a abertura e fechamento da barra? Um total de quatro coletas foi realizado entre março e outubro de 2008 em três áreas úmidas localizadas na planície de inundação da Lagoa do Peixe que recebiam influência da abertura artificial da barra e em duas áreas úmidas sem a influência da abertura da barra (áreas controle). Um total de 19.333 indivíduos distribuídos em 45 famílias de macroinvertebrados aquáticos foi amostrado nas áreas úmidas estudadas. A riqueza de macroinvertebrados (F1,3= 41, 645, p = 0, 008) e abundancia (F1,3= 1499,37; p < 0, 001) foram maiores nas áreas úmidas que não receberam influência da abertura artificial da barra (áreas controle) do que naquelas sujeitas à abertura da barra. A composição de macroinvertebrados variou significativamente entre as áreas úmidas sujeitas e não sujeitas à abertura da barra (F1,16= 6, 2422, p < 0, 001). Os resultados obtidos nesse estudo sugerem que a abertura artificial da barra da Lagoa do Peixe afeta a dinâmica da comunidade de macroinvertebrados aquáticos em áreas úmidas costeiras no Sul do Brasil.
The Lagoa do Peixe located in the Parque Nacional da Lagoa do Peixe – South of Brazil - has its connection with the sea artificially opened every year in the end of winter. However, this management is being accomplished without assessing the impacts of the sandbar opening in the aquatic biodiversity of the region’s humid areas. The following questions were tested in this study: 1) The richness, the abundance and the composition of macroinvertebrates in the wetlands of the Lagoa do Peixe vary temporally with the opening and closing of the sandbar? 2) The macroinvertebrates community range’s pattern varies with the opening and closing of the sandbar? A total of four collections was accomplished between March and October 2008 in three humid areas located in the Lagoa do Peixe flooding plain that were influenced by the artificial opening of the sandbar in two humid areas without being influenced by the opening of the sandbar (control areas). A total of 19,333 individuals distributed in 45 families of aquatic macroinvertebrates was sampled in the humid areas studied. The macroinvertebrates richness (F1,3= 41, 645, p = 0, 008) and abundance (F1,3= 1499,37; p < 0, 001) were superior in the humid areas that weren’t influenced by the artificial opening of the sandbar (control areas) than in those ones subjected to the opening of the sandbar. The macroinvertebrates composition significantly ranged between the humid areas subjected and the ones not subjected to opening of the sandbar (F1,16= 6, 2422, p < 0, 001). The obtained results in this study indicate that the artificial opening of the Lagoa do Peixe sandbar affects the dynamics of the associations of aquatic macroinvertebrates in humid coastal areas in the South of Brazil.

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34

Barnes, Peter Brendan. "Environmental impacts and the ecology of sponges and ascidians in south-eastern Australian coastal lakes and lagoons." Department of Biological Sciences - Faculty of Science, 2009. http://ro.uow.edu.au/theses/849.

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Estuaries worldwide are under threat from urbanisation and development and will need effective management for their successful conservation. Coastal lakes and lagoons have been identified as one of the estuary types most susceptible to human impacts largely because of their isolated nature and slow flushing times. Management of estuaries will be most effective when based on a sound scientific understanding of the patterns of distribution, biology and ecology over the full range of biodiversity of these systems, however, such an understanding is lacking for many systems and many taxa. Studies of sponges and ascidians in coastal lakes and lagoons are rare compared to other taxa, particularly in the southern hemisphere. This study represents the first detailed scientific investigation of the ecology of sponges and ascidian in coastal lakes and lagoons of southeastern Australia. Consequently, a large part of this thesis was devoted to quantifying basic patterns of distribution. I started with a pilot study to develop an effective sampling design, followed by large-scale comparisons among different types of lake, comparisons among habitats within lakes and an environmental impact study. I concluded with a manipulative experiment to examine processes responsible for smallscale patterns of distribution of sponges in seagrass meadows.In the pilot study, distributions of sponges and ascidians were quantified at a hierarchy of three spatial scales in each of two coastal lakes. Nested analyses of variance were then used to identify spatial scales at which variation was significant. Most sponges and ascidians were very patchily distributed at a range of spatial scales from 10s of metres up to 100s of kilometres. Unlike other published examples of cost– benefit analyses, very few taxa were widespread over the larger spatial scales. Cost– benefit analyses done to determine the optimal sampling design revealed inclusion of patchily distributed taxa in analyses improved the overall precision of sampling for comparisons of assemblages among lakes.Large-scale comparisons of assemblages of sponges and ascidians were made among lakes of different size (big versus small), opening regime (mostly open to the ocean versus mostly closed) and level of environmental modification (extensively modified versus more pristine). Similar to other taxa studied in coastal lakes, in general there were more species in lakes mostly open to the ocean compared to the mostly closed lakes, and importantly, no sponges and only one species of ascidian was found in the small closed lakes. There also appeared to be an effect of the level of modification of a lake with relatively smaller abundances of ascidians in extensively modified lakes, and a complete absence of sponges from one of the extensively modified lakes.Habitat-associated patterns were examined at smaller spatial scales by comparing the distributions of sponges and ascidians with the species composition and percentage cover of seagrass and macroalgae within two lakes; St Georges Basin and Wallis Lake. Several patterns of association were observed, but these varied among species of sponge and ascidian. In St Georges Basin, the most common sponge, Aplysinella cf. rhax and the native ascidian Pyura stolonifera were positively correlated with the seagrass, Posidonia australis. In contrast, the introduced ascidian, Styela plicata was more abundant in areas dominated by the seagrass, Zostera capricorni. In Wallis Lake, sponges were most diverse and some species most abundant in large beds of the macroalga, Lamprothamnion sp., while other sponges were found only on the holdfasts of brown macroalgae. In both lakes, sponges were generally less common in areas dominated by dense meadows of the seagrass, Zostera capricorni.Among the many anthropogenic impacts threatening the ecology of coastal lakes, the discharge of cooling water from coal-fired power stations represents an almost ideal case study from which to develop appropriate sampling regimes for detecting impacts on sponges and ascidians. Using reference locations both within and outside Lake Macquarie which has two cooling water outlets, I found assemblages of sponges and ascidians were often more diverse, more abundant and less temporally variable near to the outlets compared to reference locations.Based on the observation that the sponge, Suberites sp. which contains photosynthetic symbionts was absent from meadows of dense Zostera capricorni, I used in situ manipulative experiments in Smiths Lake to investigate processes which maybe affecting their distribution. Individual Suberites sp. were shaded, had water flow reduced and were transplanted into areas of dense Z. capricorni. There were no measurable short-term effects of shading or reduced water flow, but transplanted sponges were quickly eaten and I concluded predation by fish was likely to be a key process determining small-scale patterns of distribution of Suberites sp. in seagrass meadows. This result was in stark contrast to the majority of previous studies of the effects of seagrass habitat complexity on predation which have found predation to decrease with increasing density or complexity.In conclusion, I have sought to provide sound scientific information to aid in the management of these systems. A simple, but nevertheless key finding was that sponges and ascidians are indeed present and widespread in coastal lakes and lagoons of southeastern Australia and should not be continually overlooked in the management and conservation of these systems. Conservation will be complex and requires an understanding of environmental impacts and the consequences of management on the full range of biodiversity. The distributions of sponges and ascidians at large ‘lakewide’ scales appear to behave similarly to other taxa. Management strategies which change the characteristics of a lake at these large spatial scales such as artificial openings of entrances could therefore be predicted to have similar effects across a range of taxa including sponges and ascidians. In contrast, at smaller spatial scales such as the complexity of seagrass meadows, some species of sponges and ascidians may behave very differently from other taxa. At present, our understanding of these naturally variable and complex systems is incomplete and will require ongoing scientific investigation to identify natural patterns of distribution, environmental impacts, important natural processes and the ecological consequences of management strategies.

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Santos, Cristiane Bahi dos. "Assembléias de diatomáceas em sedimentos holocênicos no estremo sul do Brasil : reconstruções paleoambientais." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2011. http://hdl.handle.net/10183/32700.

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O presente trabalho descreve as assembléias de diatomáceas, presentes em um perfil sedimentar na Lagoa do Peixe, Litoral Médio do Rio Grande do Sul, com o objetivo de efetuar a reconstrução paleoambiental e identificar os períodos de maior influência marinha e hidrodinâmica, como conseqüências das variações do nível do mar ocorridas durante o Holoceno. O testemunho de sondagem T09 foi selecionado para estudo, devido à boa recuperação e à presença de um espesso pacote de lama próximo à base. Os resultados da análise de diatomáceas revelaram a presença de 114 táxons, constituintes das assembléias fósseis, dominadas pelo complexo de Paralia (Paralia fenestrata, P.sulcata e Paralia sp.), associados à táxons marinhos, entre eles: Auliscus caelatus e Triceratium favus; e os táxons marinhos salobros: Cyclotella striata, Dimeregramma marinum, D. minor var. minor e Psamococconeis disculoides, entre outros. Os resultados da distribuição, tafonomia e paleoecologia do complexo de Paralia e das assembléias presentes ao longo do perfil, forneceram maior detalhamento evolutivo do sistema lagunar associadas à ocorrência de três oscilações de alta freqüência do nível do mar na PCRS, interligadas à períodos de maior influência hidrodinâmica, comprovando que a morfologia lagunar sofreu intensas modificações ao longo do tempo. Entre as idades de 7420-7020 e 5370-5340 anos AP, ocorreram duas oscilações de alta freqüência, que atingiram o sistema lagunar, afetando diretamente as assembléias presentes. Entre as idades de 5370-5340- 2340-2060 anos AP, ocorreu uma terceira oscilação de alta freqüência, concordando com o máximo transgressivo registrado para a região sul do Brasil. A distinta composição observada entre as assembléias fósseis e atuais (preservadas em sedimentos superficiais) é um indicativo de que durante o Holoceno, a Lagoa do Peixe comportou-se como um sistema lagunar, apresentando características morfosedimentares, geomorfológicas, hidrodinâmicas e ecológicas, totalmente diferente das condições atuais, onde assume configurações de lagoa costeira semi-fechada, de ligação restrita com o oceano por meio de um canal de ligação.
This paper describes the diatom assemblages present in a sediment profile in the Lagoa do Peixe, Middle Littoral of Rio Grande do Sul, in order to make the palaeoenvironmental reconstruction and identify periods of increased marine influence and hydrodynamics, as a consequence of changes sea level occurred during the Holocene. The drill core T09 was selected for study due to good recovery and the presence of a thick pack of mud near the base. The results of diatom analysis revealed the presence of 114 taxa, constituents of fossil assemblages, dominated by complex Paralia (Paralia fenestrata, P.sulcata and Paralia sp.), associated with marine taxa: Auliscus caelatus and Triceratium favus, brackish and marine taxa: Cyclotella striata, Dimeregramma marinum, D. minor var.minor and Psamococconeis disculoides, among others. The results of the distribution, taphonomy and paleoecology of Paralia complex assemblages, present along the profile, provided a more detailed evolution of the lagoon system associated with the occurrence of three high-frequency oscillations in sea level in the PCRS, linked to periods of greater influence hydrodynamics, proving that the lagoon morphology underwent enormous changes over time. Between the ages of 7420- 7020 and 5370-5340 years BP, there were two high frequency oscillations, which reached the lagoon system, directly affecting the assemblages present. Between the ages of 5370-5340- 2340-2060 years BP, there was a third high frequency oscillation, in agreement with the transgressive maximum recorded for the southern region of Brazil. The difference in composition observed between the modern and fossil assemblages (preserved in surface sediments), is an indication that during the Holocene, the Lagoa do Peixe, behaved like a lagoon system, whose morphosedimentar, geomorphological, hydrodynamic and ecological characteristics were totally dissimilar from actual conditions representing semi-enclosed coastal lagoon which had restricted connection with the oceano through an inlet.

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Nandi, Nandi [Verfasser], Jürgen [Akademischer Betreuer] Heinrich, Jürgen [Gutachter] Heinrich, and Gunter [Gutachter] Menz. "The Ecological Dynamics of a Coastal Lagoon : A Study of the Morphodynamics, Land Use Change, Community Participation, and Spatial Planning of the Segara Anakan Lagoon in Indonesia / Nandi Nandi ; Gutachter: Jürgen Heinrich, Gunter Menz ; Betreuer: Jürgen Heinrich." Leipzig : Universitätsbibliothek Leipzig, 2015. http://d-nb.info/1239423586/34.

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Jayawardane, P. A. A. T. "Fishery biology and population dynamics of shrimps (Penaeus indicus and Metapenaeus dobsoni) in the lagoon and the coastal area of Negombo, Sri Lanka." Thesis, University of Stirling, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365130.

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38

Compte, Ciurana Jordi. "Food webs of Mediterranean coastal wetlands." Doctoral thesis, Universitat de Girona, 2010. http://hdl.handle.net/10803/7879.

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En aquesta tesi doctoral s'han estudiat els efectes directes i indirectes de dos tipus d'espècies claus de la comunitat aquàtica dels aiguamolls de l'Empordà (aiguamolls costaners mediterranis amb una xarxa tròfica senzilla). S'han realitzat experiments al camp utilitzant microcosmos i mesocosmos i els resultats han estat analitzats mitjançant tres aproximacions: la taxonòmica, la funcional i la de mides. S'ha comprovat que en situacions amb absència de predadors i dominància d'una única espècie en el zooplàncton (en aquest cas Calanipeda aquaedulcis i Daphnia magna), la segregació del recurs entre els diferents estadis de desenvolupament de la mateixa espècie zooplanctònica és una estratègia per evitar la competència intraespecífica en condicions de limitació de recurs. Per altra banda, la presència de diferents top-predators a la comunitat aquàtica (en aquest cas la medusa Odessia maeotica i el peix Aphanius iberus) desencadena una cascada tròfica en el plàncton però amb efectes top-down diferents segons el top-predator.
In this PhD, direct and indirect effects of key species were studied in the aquatic community of the Empordà wetlands (Mediterranean coastal wetlands with a simple food web). Different field experiments were carried out using microcosms and mesocosms. To analyze the results, three approaches were used: taxonomic, functional and size-based. Results obtained from the experiments confirm that, in situation with absence of predator and dominance of single zooplanktonic specie (in this case Calanipeda aquaedulcis and Daphnia magna), resource partitioning among different developmental stages of same zooplanktonic specie is a strategy to reduce the intraespecific competence when the resource is limiting. On the other hand, the presence of different top-predators in aquatic community (in this case the jellyfish Odessia maeotica and the Iberian toothcarp Aphanius iberus) triggers a trophic cascade in plankton, however they have different top-down effects according to top-predator.

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Bulit, Celia. "A geostatistical analysis of ciliate patches : their identification, structural characteristics, and spatial and temporal dynamics using a tropical coastal lagoon as a natural laboratory." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402300.

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Jacques, Saulo Machado de Souza. "Influência de fatores ascendentes sobre a produção bacteriana em ecossistemas aquáticos continentais tropicais." Universidade Federal de Juiz de Fora, 2011. https://repositorio.ufjf.br/jspui/handle/ufjf/2097.

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Bactérias heterotróficas são importantes componentes do plâncton, participando ativamente do ciclo do carbono em ecossistemas aquáticos, como por exemplo, através da incorporação de carbono à biomassa pelo processo de produção bacteriana (PB). Alterações nos ecossistemas aquáticos influenciam a atividade bacteriana e, consequentemente, o ciclo do carbono nestes sistemas. Este estudo se propôs a avaliar a influência da temperatura, da concentração de carbono orgânico dissolvido (COD) e da disponibilidade de nutrientes sobre a PB em cinco lagoas costeiras tropicais, que representam um gradiente natural de concentração de carbono (12; 18,3; 46,7; 86 e 117,1 mg/L). Amostras de água de todas as lagoas foram incubadas em três temperaturas diferentes (25, 30 e 35º C), combinadas fatorialmente com a adição de nutrientes: carbono (C), nitrogênio (N), fósforo (P) e nitrogênio + fósforo (NP). Os resultados revelaram que a adição de nutrientes estimulou a PB, mas de maneira distinta em cada uma das lagoas. Em sistemas com maiores concentrações de COD, a adição de C estimulou a PB, enquanto que em lagoas com menores concentrações, a adição de N e P resultou maiores taxas de PB. No geral, o aumento de temperatura afetou negativamente a PB. Segundo os resultados observados, o efeito da temperatura e da adição de nutrientes sobre a PB é dependente de algumas características do estoque de carbono dos ecossistemas aquáticos, como sua qualidade para o consumo bacteriano. Desta forma, espera-se que a temperatura e a qualidade de C sejam mais importantes sobre as taxas de PB em ecossistemas com maiores concentrações de COD húmico, enquanto em ecossistemas com baixa concentração de COD estes dois fatores exercem fraca ou nenhuma influência sobre PB. Diante dos atuais eventos de eutrofização e alterações climáticas, espera-se observar alterações da atividade da comunidade vii bacteriana em ecossistemas aquáticos, com consequência para toda a teia alimentar. Os resultados deste trabalho apontam que fatores como a qualidade do substrato e a estrutura da comunidade bacteriana merecem especial atenção em estudos futuros para uma melhor compreensão da influência da temperatura e de nutrientes sobre a PB em ecossistemas aquáticos húmicos tropicais.
Heterotrophic bacteria are important components of plankton, actively participating in the carbon cycle in aquatic ecosystems and incorporating carbon biomass through the process of bacterial production (BP). Changes in ecosystems influence bacterial activity and thus the carbon cycle in these systems. This study aimed to evaluate the influence of temperature, dissolved organic carbon (DOC) concentration and nutrient availability on the BP in five tropical coastal lagoons, which represented a gradient of carbon concentration (12; 18,3; 46,7; 86 and 117,1 mg/L). Water samples from the lagoons were incubated at three different temperatures (25, 30 and 35º C) factorially combined with the addition of nutrients: carbon (C), nitrogen (N), phosphorus (P) and nitrogen + phosphorus (NP). The results revealed that the addition of nutrients stimulates the BP, but differently in each of the lagoons. In systems with higher DOC concentration, the addition of C stimulated the BP, while in lakes with lower DOC, the addition of N and P resulted in higher BP rates. In general, the temperature increase negatively affected BP. According to the results, the effect of temperature and nutrient addition on the BP is dependent of some characteristics of the carbon stock of aquatic ecosystems, as well on its quality for bacterial consumption. Thus, it is expected that the temperature and quality of C are more important on the rates of BP in the ecosystem with the highest humic carbon concentrations, while in ecosystems with low DOC, these two factors play weak or no influence on BP. Given the current events of eutrophication and climate change, a reduction in the activity of bacterial communities in aquatic ecosystems would be expected, with consequences for the entire food web. The present results point out that factors like substrate quality and ix the structure of the bacterial community deserve special attention in future studies for a better understanding of the influence of temperature and nutrient on BP in humic tropical aquatic ecosystems.

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Baitelli, Ricardo. "Evolução Paleogeográfica do Sistema de Paleodrenagem do Rio Jacuí na Planície Costeira do Rio Grande do Sul." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2012. http://hdl.handle.net/10183/56850.

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Regiões costeiras são moldadas por inúmeros eventos transgressivos e regressivos, responsáveis pela presença de vales incisos e ambientes deposicionais associados. Este estudo foi desenvolvido na região da Lagoa dos Patos e analisou um conjunto de dados que permitiu traçar um novo panorama evolutivo para a Planície Costeira do Rio Grande do Sul. Para a elucidação de alguns aspectos evolutivos, foi feita a integração de dados sísmicos, sedimentológicos, paleontológicos e isotópicos. Assim, a partir dos elementos arquiteturais sismodeposicionais do prisma sedimentar costeiro, foi estabelecido um modelo de formação e preenchimento sedimentar do sistema de paleodrenagens e definindo posições pretéritas do rio Jacuí. Foram levantados aproximadamente mil quilômetros de linhas sísmicas de reflexão e alta resolução na região da Lagoa dos Patos que permitiram a interpretação sobre processos sedimentares, variações relativas do nível do mar, paleotopografia, entre outros. Os dados sísmicos mostraram o seccionamento, por cursos fluviais pretéritos, de diferentes depósitos sedimentares existentes na costa gaúcha, onde foram definidas quatro sequências sismodeposicionais. Estas sequências revelaram informações que permitiram a discriminação de descontinuidades estratigráficas de alta frequência (limite de sequência), que conduziram à caracterização de depósitos fluviais, estuarinos e marinhos, dentro de um contexto de sequência estratigráfica. Sondagens estratigráficas realizadas no interior da Lagoa dos Patos, nas localidades de Bojuru, Mostardas e Palmares do Sul, forneceram material fóssil nos quais foram identificados grupos taxonômicos que também serviram às análises isotópicas de carbono e oxigênio. Os valores de δC13 nas amostras revelaram condições transgressivas e regressivas e, aliado aos valores de δO18, mostraram que as condições ambientais locais foram semelhantes para Bojuru (paleocamaquã) e Palmares (primeira saída para o mar do paleojacuí) e diferentes para Mostardas (segunda saída para o mar do paleojacuí). Os cursos do paleojacuí e paleocamaquã deram origem a inlets, em períodos de mar alto e atuaram como incisivos canais em períodos de mar baixo. O paleocamaquã manteve seu curso praticamente inalterado no último meio milhão de anos, seguindo na direção da localidade de Bojuru. O paleojacuí fixou sua saída para o mar entre as latitudes 30°S e 31°S e, em períodos de mar baixo, escavou profundamente a planície costeira e plataforma adjacente fazendo com que seu leito atinjisse cotas superiores a 50 metros abaixo do seu nível atual. Esta primeira saída do paleojacuí para o mar na região de Palmares do Sul, através do sistema de ilha‐barreira II, foi obstruído pelos sedimentos do sistema de ilha‐barreira III, em desenvolvimento, em 133 ka. Este evento ocorreu preferencialmente para oeste e sobre a planície de inundação e os depósitos de canal do antigo rio Jacuí, mostrando ter sido um dos maiores (em extensão) e mais longos (em duração) episódios transgressivos. A segunda saída do paleojacuí para o mar, agora mais a sul, na região de Mostardas, assim como a saída do paleocamaquã na região de Bojuru, que fluíam entre os sedimentos do sistema ilha‐barreira III, foram fechadas pelos sedimentos do sistema ilha‐barreira IV, em formação, há 6 kyr. Esta configuração de sistema laguna‐barreira se mantem, ao menos, até os dias atuais.
Coastal regions are shaped by numerous transgressive and regressive events, responsible for the presence of incised valleys and associated depositional environments. The study carried out in the region of Lagoa dos Patos analyzed a dataset that allowed to outline a new evolutionary scenario for the Coastal Plain of Rio Grande do Sul. For the elucidation of some aspects of evolution, was made the integration of seismic, sedimentological, palaeontological and isotopic data. Thus, a study of the architectural elements of the coastal sedimentary prism was conducted throughout this work, setting up a model for the formation and filling of sedimentary system and defining the positions of the preterit Jacuí river. About a thousand kilometers of high‐resolution seismic reflection lines in the region of the Lagoa dos Patos allowed the interpretation of sedimentary processes, relative changes in sea level, ancient topography, among others. The seismic data showed different sedimentary deposits on the shore of Rio Grande do Sul sectioned by ancient waterways, where four seismic depositional sequences were defined. These sequences revealed information that allowed the discrimination of high‐frequency stratigraphic discontinuities (sequence boundary), which led to the characterization of fluvial deposits, estuarine and marine environments, within a stratigraphic sequence context. Stratigraphic drilling conducted within the Lagoa dos Patos, in the localities of Bojuru, Mostardas and Palmares do Sul, provided material on which fossil taxons were identified and also served for the isotopic analysis of carbon and oxygen. The δC13 values revealed transgressive and regressive conditions, together with δO18 values, showed that local environmental conditions were similar to Bojuru (paleocamaquã) and Palmares (first paleojacuí exit to the sea) and different for Mostardas (second paleojacuí exit to the sea). The courses of paleojacuí and paleocamaquã performed as inlets, in periods of high sea level and acted as incisors channels during periods of low sea level. The paleocamaquã maintained its course virtually unchanged over the last half million years, following the direction of the town of Bojuru. The paleojacuí fixed its outlet to the sea between latitudes 30°S and 31°S, and during periods of low sea, dug deep into the coastal plain and adjacent platform making his bed reach deeps greater than 50 meters below its current level. This first paleojacuí outlet to the sea, in the region of Palmares do Sul, through the barrier island II system was blocked by sediments from barrier island III system, in development, at 133 ka. This event occurred preferentially to the west and on the floodplain and channel deposits of ancient river Jacuí showing that was one of the largest (in length) and longest (in duration) transgressive episodes. The second output to the sea of paleojacuí, now further south, in the region of Mostardas, as well as the output of paleocamaquã at Bojuru, that flowed between sediments from barrier island III system, were closed by sediments from barrier island IV system at 6 kyr. This last lagoon‐barrier system configuration keeps, at least, until today.

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Bitencourt, Volney Junior Borges. "Geomorfologia e arquitetura deposicional de uma planície de cordões litorâneos lacustre, litoral norte do RS - Brasil." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/114396.

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Cordões litorâneos regressivos arenosos do tipo praia (beach ridge) e do tipo duna frontal (foredune ridge) são feições morfológicas comuns em costas deposicionais com abundância de sedimento. No presente estudo, a morfologia superficial, estratigrafia e a origem de uma planície de cordões ocorrentes na Lagoa dos Quadros, litoral norte do Rio Grande do Sul, são investigadas. Abordagens em superfície através de análises de fotografia aéreas, análises de imagens de satélite e altimetria de detalhe, em junção com dados em subsuperfície oriundos de perfilagens geofísica com uso de GPR e dados sedimentológicos provenientes de testemunhos de sondagens rasos proporcionaram elucidar as fáceis que compõem a arquitetura deposicional, bem como especificar as características geométricas superficiais dos cordões. Datações por 14C permitiram estimar o estágio do início do desenvolvimento da planície de cordões, e a modelagem de ondas e análise de ventos propiciaram inferir as condições fluidodinâmicas envolvidas em sua gênese. A planície de cordões é composta por cordões de praia e cordões de duna frontal, ou seja, uma barreira complexa. Esses cordões são o resultado do desenvolvimento de uma sequência regressiva sobre uma fácies basal de fundo (lagunar). Essa sequência regressiva é composta por depósitos de antepraia, de pós-praia/face de praia, dunas frontais e depósitos de leque de sobrelavagem. A fácies basal de fundo lagunar registra a fase de agradação e progradação da fácies de fundo lagunar do sistema lacustre, ocorrida entre 7047 ± 197 ka e 6230 ± 122 ka. A planície é composta por 20 cordões contínuos e semi-contínuos, de baixa amplitude e espaçados de 5 a 50 m. A migração de campos de dunas transgressivos da barreira de Curumim para dentro da lagoa (entre 7,1 e 5,5 ka) podem ter sido uma importante fonte de areia para a formação da planície de cordões litorâneos regressivos da margem NE da Lagoa dos Quadros.
Beach ridges and foredune ridges are morphological elements largely present in depositional coasts with abundant sediment supply. In this study, the morphology, the stratigraphy and genesis of a strandplain (sand ridge plain) developed at the Quadros lagoon, northern littoral of Rio Grande do Sul, are studied. Photographic surveys, analysis of satellite imagery and topographic surveying plus geophysical data collected with GPR and sedimentological data from drill holes allowed elucidate the facies that make up the depositional architecture and specify the surface geometric characteristics of the ridges. Was possible to estimate the stage of development of the strandplain by 14C dating, and the modeling of waves and analysis of winds pattern have led to infer the fluid dynamic conditions involved in its genesis. The strandplain comprises beach ridges and foredune ridges, which makes a complex barrier. These ridges are results of a regressive sequence developed on a lagoon bottom basal facies. The regressive sequence comprises deposits of shoreface, deposits of beachface/ backshore, foredunes and washover fan. The lagoon bottom basal facies records the aggradation and progradation phases of the lagoon bottom facies of the lagoon system occurred between 7047 ± 197 ka and 6230 ± 122 ka. The strandplain comprises 20 continuous and semi-continuous ridges, low amplitude and spaced 5-50 m. The migration of transgressive dune fields of Curumim barrier to inside the lagoon (between 7.1 and 5.5 ka) may have been an important source of sand to form the strandplain of NE margin of Quadros Lagoon.

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Sampaio, Gláucia Freitas. "Cianobactérias como parâmetro de qualidade ambiental: um estudo no complexo lagunas de Jacarepaguá." Universidade do Estado do Rio de Janeiro, 2008. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=7517.

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O Complexo Lagunar de Jacarepaguá, localizado no município do Rio de Janeiro, região sudeste do Brasil, é formado pelas lagunas de Jacarepaguá, Camorim, Tijuca e Marapendi. Estas lagunas estão interligadas ao mar pelo canal da Joatinga e têm como afluentes rios e canais que vertem dos maciços da Tijuca e da Pedra Branca. Recebem esgotos sanitários e efluentes industriais, além de contribuições difusas de águas de drenagem e circulação das massas de águas de várias origens, com elevada carga de poluição. A eutrofização cultural aliada aos processos de evolução de ecossistemas costeiros produziu um estado de degradação destas águas com constantes florações de cianobactérias potencialmente tóxicas. O presente estudo tem como objetivo avaliar a ocorrência das cianobactérias (Classe Cyanophyceae) no Complexo Lagunar de Jacarepaguá e corroborar a hipótese de serem boas indicadoras de qualidade ambiental de águas salobras. Foi realizado um monitoramento ambiental nas lagunas de Jacarepaguá, Camorim, Tijuca e Marapendi, nos anos de 2004 a 2006, sendo analisados parâmetros físicos, químicos e biológicos. Os resultados obtidos demonstraram a dominância e a persistência das cianobactérias em elevadas concentrações de nutrientes, caracterizando a hipereutrofização dessas lagunas. As estratégias ecológicas das cianobactérias garantiram sua dominância em quase todo o período amostral e demonstraram ser um refinado sensor das variáveis ambientais. A salinidade não foi um fator de limitação ao desenvolvimento desses microorganismos. Desta forma, este estudo, oferece subsídios para gestão de recursos hídricos, corroborando com a legislação CONAMA 357/05-MMA, na sugestão de indicação deste parâmetro de qualidade ambiental também para ambientes salobros na classe 1.
The Jacarepaguá Lagoon Complex, located in the state of the Rio of Janeiro, in Southeast of Brazil, is formed by the lagoons of Jacarepaguá, Camorim, Tijuca and Marapendi. These lagoons are interconnected to the sea by the Joatinga canal and receive contribution from tributary rivers and channels that come from Tijuca and Pedra Branca massifs. They receive industrial and domestic effluents, including diffuse contributions of the drainage basin, as well as water circulation from several origins, with a high pollution load. The cultural eutrophication associated with coastal ecosystems evolution processes, have produced a state of degradation of these waters with frequent waterblooms of potentially toxic cyanobacteria. The objective of the present study is to evaluate the presence of Cyanobacteria (Class Cyanophyceae) in the Jacarepaguá Lagoon Complex and also to corroborate the hypothesis of using them as a good bioindicators of environmental quality in brackish waters. An environmental monitoring program has been carried out in the lagoons of Jacarepaguá, Camorim, Tijuca and Marapendi from 2004 to 2006, including physical, chemical and biological parameters analysis. The results showed the dominance and persistence of Cyanobacteria at high concentrations of nutrients, characterizing the hypereutrofication of these lagoons. The ecological strategies of Cyanobacteria were responsible for their dominance in almost the whole period of study and demonstrated that they can be used as a good sensor of environmental variables. The salinity did not demonstrate to be a limiting factor to the development of these microorganisms. In this way, this study provides subsidies for water resources management, corroborating with Brazilian legislation (CONAMA 357/05- MMA) suggesting the inclusion of Cyanobacteria as a parameter of environmental quality in brackish environments classified as Class 1.

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Adomat, Friederike [Verfasser], Eberhard [Akademischer Betreuer] Gischler, and Wolfgang [Akademischer Betreuer] Oschmann. "Holocene evolution of coastal lagoon environments in Belize, Central America : analysis of stratigraphic patterns, mollusk shell concentrations and storm deposition / Friederike Adomat. Gutachter: Eberhard Gischler ; Wolfgang Oschmann." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2016. http://d-nb.info/1098308182/34.

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Carvalho, Regina Paula Benedetto de. "Ocupação dos solos em terrenos marginais às lagoas costeiras: mudanças e perspectivas ambientais frente à expansão urbana - o caso da lagoa de Jacarepaguá (Rio de Janeiro)." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=4828.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O objetivo do trabalho é analisar a lagoa de Jacarepaguá e a ocupação no seu entorno de forma multitemporal, contribuindo para o melhor entendimento das atuais condições ambientais da Baixada de Jacarepaguá. A metodologia adotada buscou identificar mudanças físicas do meio a partir 1980 através da elaboração, comparação e análise de mapas de ocupação e uso dos solos relativos aos anos de 1984, 1992, 2001 e 2010, e da identificação da qualidade da água da lagoa de Jacarepaguá, das suas condições de profundidade, tamanho do espelho dágua e de sua relação com a população local. Com isso foi possível retratar formas de integração entre os processos naturais e sociais em um dado espaço-tempo assim como estabelecer tendências futuras desse ambiente. Os resultados mostram que de tempos em tempos há uma refuncionalização do espaço, que se reflete não só na conformação dos terrenos marginais alagadiços mas também nas condições físicas da própria lagoa de Jacarepaguá. Seu espelho dágua vem sendo confinado pelas formas de ocupação nas áreas das bacias fluviais e nos seus terrenos marginais (impermeabilização, aterros e obras de drenagem) fazendo com que haja uma estabilidade relativa na sua dimensão areal e também no volume de suas águas. A lagoa apresenta dados históricos de poluição por esgoto doméstico que têm acelerado suas condições naturais de assoreamento e comprometido à qualidade de suas águas. E mesmo havendo projetos e obras de saneamento para o local, verifica-se que tem havido um aumento da poluição da lagoa principalmente na sua porção oeste, conforme o resultado das análises realizadas com os dados temporais disponíveis de DBO, fósforo, Nitrogênio Kj, OD e salinidade. Isto pode ser explicado pela tendência atual da expansão urbana rumo a essa direção. Constatou-se que apesar de, por algum tempo, os tipos de terreno terem condicionado as formas de ocupação, atualmente o processo se inverteu, sendo a ocupação indutora e recondicionante da estruturação do meio. São apresentadas e caracterizadas diversas formas e respectivos tipos de usos do solo na área. Conclui-se que as condições ambientais da lagoa de Jacarepaguá e suas perspectivas futuras dependem atualmente mais da forma com que a sociedade quer e pretende incorpora-la ao seu ambiente do que da dinâmica natural do sistema físico do qual faz parte.
The aim of this paper is to analyse the lagoon of Jacarepaguá and the occupation of its outskirts throughout the multi-temporal, contributing for a better understanding of the current environmental conditions of the lowland of Jacarepaguá. The adopted methodology seeked to identify the physical changes of the environment from 1980 s on, through the elaboration, comparison and analysis of occupation maps and the usage of soils related to the years of 1984, 1992, 2001 and 2010, and the identification of the water quality of the Lagoon of Jacarepagua, of its depth conditions, the size of the water mirror and its relation to the local community. This way, it was possible to portray ways of integration between the natural and social processes in a given time-space, as well as to establish future tendencies of this environment. The results show that from time to time there is a refunctionalization of the space, which reflects not only in the conformation of the marginal swampy terrains, but also in the physical conditions of the Lagoon of Jacarepagua itself. The lagoon s water mirror has been confined by the means of occupation in the river basins and its marginal terrains (waterproofing, landfills and drainage work) creating a relative stability in its sandy dimension and also in its water volume. The lagoon presents some historical data of pollution through domestic sewer which has accelerated its natural conditions of silting up and compromised the quality of its waters. And even though there are some projects and sanitation works for the place, it is verified that there has been a pollution increase of the lagoon, mainly, in its western portion, as has shown the results of the accomplished analyses with the BOD (Biochemical Oxygen Demand) available data, phosphorus, nitrogen, DO (Dissolved Oxygen) and salinity. This can be explained by the current tendency of the urban expansion due to this direction. It is verified, despite the fact that, for a while, the types of terrain have conditioned its ways of occupation. Nowadays the process has inverted, being the inductorial occupation and reconditioning of the environment structuration. It is presented and characterized several forms and respective types of soil usage in the area. Thus, the environmental condition of the Lagoon of Jacarepagua and its future perspectives depends on, nowadays, more in the way in which the society want and intend to incorporate to its environment, than to the natural dynamic of the physical system to which it is belonged.

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Oliveira, Rafael Rosas. "Caracterização do estado trófico e da qualidade da água de um sistema lagunar costeiro urbano: estudo de caso da Lagoa Rodrigo de Freitas, RJ." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=7580.

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O estudo da dinâmica dos parâmetros físicos, químicos e biológicos da água em lagoas costeiras é essencial para entender o funcionamento destes ecossistemas; o que por sua vez permite o desenvolvimento de estratégias adequadas de gerenciamento e conservação de seus recursos. Neste estudo, analisou-se a qualidade da água da Lagoa Rodrigo de Freitas (Rio de Janeiro/RJ) e dos seus principais tributários. Foram utilizados os dados oriundos do projeto de monitoramento da qualidade da água realizado pela SMAC/RJ, entre dezembro de 2011 e dezembro de 2012. O objetivo precípuo foi compreender a dinâmica espacial e temporal da variação do estado trófico e da qualidade da água, assim como avaliar a exequibilidade e aplicabilidade de índices multimétricos (IQA, IET, ICE, IC, TRIX) ao projeto de monitoramento ambiental da LRF. Para tanto, foram realizadas coletas mensais e semanais da água superficial em cinco pontos amostrais, na LRF, e cinco pontos nos rios/canais. Em seguida, análises físico-químicas e biológicas foram realizadas. Os resultados obtidos mostraram relativa homogeneidade espacial e elevada variação sazonal da qualidade da água superficial. Os índices aplicados aos dados indicaram uma variação temporal representativa do estado trófico e da qualidade da água, sendo as classificações para os rios e canais diferentes às verificadas na LRF. Esta apresentou variação entre supereutrófica e hipereutrófica, já os primeiros foram mesotróficos. A qualidade da água da LRF apresentou majoritariamente entre moderada a boa. Os rios e canais foram classificados ruins e médios. Concluiu-se que diferentes modelos podem resultar em diferentes classificações de níveis de trofia e qualidade da água. Análises estatísticas de tendência indicaram estabilidade da qualidade da água, sem uma projeção representativa de melhoria da qualidade hídrica. Já análises multivariadas (RDA, PCA BEST, SIMPER, ANOSIM, MDS e CLUSTER) mostraram um elevado dinamismo da comunidade fitoplanctônica com nítida resposta às oscilações de variáveis físico-químicas específicas, apesar da dominância recorrente por cianobactérias.
The study of the dynamics of physical, chemical and biological parameters in coastal lagoons is essential to understand how these ecosystems function, which enables the development of appropriate strategies for management and conservation of its water resources. This research analyzed the water quality of the Rodrigo de Freitas lagoon (LRF), located in the city of Rio de Janeiro/RJ, and its main tributaries. Data from the Water Quality Monitoring Program conducted by Secretaria Municipal de Meio Ambiente do Rio de Janeiro between December 2011 and December 2012 were used. The main objective of this study is clarify the spatiotemporal dynamic of the variation of the trophic state and water quality of the LRF, and assess the applicability and feasibility of specific multimetric indices (IQA, IET, ICE, IC, TRIX). In order to achieving this goal, weekly and monthly surface water samplings were performed at five stations in the LRF and five stations in the rivers/channels. Physico-chemical and microbiological (bacteriological and phytoplankton) variables were analyzed in situ or in the laboratory. The results showed relative spatial homogeneity and high temporal variation of the water quality. The trophic state and water quality indices classified the rivers/channels as mostly mesotrophic and the LRF between supereutrophic and hypereutrophic. The water quality was classified between moderate to good in the LRF and medium and bad for the rivers/channels. It was concluded, therefore, that different assessment models may result in contradictory classifications of the trophic and and water quality conditions. Trend statistical analysis indicated stability of trophic conditions but without a representative prediction of improving water quality. Finally, it is emphasized that the multivariate statistical analysis (RDA, PCA BEST, SIMPER, ANOSIM, MDS and CLUSTER) demonstrated a high dynamism of the phytoplankton community in response to fluctuations in the physico-chemical characteristics, despite the recurrent dominance by cyanobacteria.

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Haskins, Craig Ian. "Impacts of climate change : some economic considerations for decision-makers in the City of Cape Town, using Langebaan Lagoon as a case study." Thesis, Stellenbosch : Stellenbosch University, 2005. http://hdl.handle.net/10019.1/50366.

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Thesis (MBA)--Stellenbosch University, 2005
ENGLISH ABSTRACT: Strong scientific evidence suggests that global warming is altering the world's climate and that this phenomenon is being accelerated as a result of human activities. Climate change is affecting weather patterns and, in addition to demonstrated sea-level rise, these in turn have and are likely to continue having significant, mostly negative, impacts - both economic and loss of life - on governments, industries and people. Ocean levels rose between 15 and 20 centimeters in the 20th century, mostly as a result of melting glaciers and thermal expansion of the oceans. The International Panel on Climate Change (IPCC, 2001a: 16) in its 2001 estimate suggests a potential rise in average sea level from nine to 88 centimeters from 1990 to 2100. Areas of risk in the City of Cape Town are residential property, infrastructure and beaches in low-lying areas. These areas are likely to be impacted as a result of increasing sea-level rise and increasing severity and frequency of storms. This study seeks to • demonstrate that sufficient evidence exists to compel decision-makers in the City of Cape Town that climate change and the impacts of sea-level rise and increasing frequency and severity of storms need to be considered in development planning; and • test cost-benefit analysis (through climate change impact analysis) as a tool for decision-makers to consider adaptation measures, using Langebaan as a case study. The research comprises a comprehensive literature study of the impacts of climate change, particularly with respect to coastal areas. A case study based on the eroding beaches at Langebaan is used to test cost-benefit analysis as a tool for decision-makers in dealing with the impacts. Despite the uncertainties associated with the impacts of climate change (time, place and extent) the issues of sea-level rise and severe storms seem to warrant further investigation, especially at a local level. This study provides local context to a global problem and makes recommendations for decision-makers in the City of Cape Town. Climate impact analysis (incorporating cost-benefit analysis) is suggested as a tool to quantify avoided damages at vulnerable coastal sites in the City of Cape Town. In conclusion, the impacts of climate change are a complex and multivariate problem. However, there are a number of identified vulnerable areas along the coastline of the City of Cape Town and using tools like climate impact analysis and cost-benefit analysis may assist in identifying, costing and managing these economic risks before the problem becomes unmanageable - a case for quantifying avoided damage.
AFRIKAANSE OPSOMMING: Sterk wetenskaplike bewyse bestaan dat globale verwarming besig is om die wêreld se klimaat te verander en hierdie verskynsel word versnel deur die mens se handelinge. Klimaatsverandering affekteer weerpatrone en bykomend tot gedemonstreerde stygende seevlakke, sal dit waarskynlik 'n langdurige en meestal negatiewe impak - beide ekonomies en lewensverlies - op regerings, industrieë en mense hê. Seevlakke het in die twintigste eeu met tussen 15 en 20 sentimeter gestyg, meestal as gevolg van smeltende ysberge en hitte uitsetting van die oseane. Die 'International Panel on Climate Change' (IPCC, 2001a: 16) het in hul skatting 'n waarskynlike seevlak styging van tussen 9 en 88 sentimeters voorspel vir die tydperk 1990 - 2100. Risikogebiede in die Stad Kaapstad is residensiële gebiede, infrastruktuur en strande in laagliggende gebiede. Hierdie gebiede sal ge-affekteer word deur stygende seevlakke en groter en meer gereelde storms. Hierdie studie poog om • te demonstreer dat voldoende bewyse bestaan om besluitnemers van die Stad Kaapstad te oortuig dat weerveranderinge en die impak van seevlakstygings en toenemende storms in aanmerking geneem moet word in ontwikkelings beplanning; en • koste-voordeel analises (deur klimaatsverandering impak analises) te beproef as 'n hulpmiddel vir besluitnemers om aanpasbare maatreëls te oorweeg, deur Langebaan as 'n voorbeeld te gebruik. Ten spyte van onsekerhede wat saamgaan met die impak van klimaatverandering (tyd, plek en omvang) regverdig die problem van stygende seevlakke en erge storms verdere ondersoek, meer spesifiek op plaaslike vlak. Hierdie studie gee plaaslike konteks aan 'n globale probleem en maak aanbevelings aan beplanners van die Stad Kaapstad. Klimaat impak analises word as hulpmiddel voorgestel om vermybare skades by kwesbare kusgebiede in die Stad Kaapstad te kwantifiseer. Ten slotte: die impak van klimaatsverandering is 'n komplekse probleem met baie fasette. Nietemin is daar verskere sensitiewe areas langs die kus van Stad Kaapstad, en klimaat impak analises en koste-voordeel analises kan help met die identifisering, kosteberekening en bestuur van hierdie ekonomiese risiko areas, voordat dit onhanteerbaar raak.

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Bettinelli, Maiara. "Assembleias de moluscos pleistocênicos no sul da planície costeira do Rio Grande do Sul: implicações na evolução do sistema Laguna-Barreira III." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/184511.

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O Sistema Laguna-Barreira III é o sistema deposicional pleistocênico mais preservado do sul da Planície Costeira do Rio Grande do Sul. A origem dessa unidade está correlacionada ao alto nível do mar do último estágio interglacial, mas até agora pouco se conhece sobre sua evolução e estratigrafia devido à escassez de afloramentos. Uma assembleia de fósseis constituída por milhares de bivalves e gastrópodes foi recuperada de perfurações e sondagens SPT (Standard Penetration Test), em profundidades de até 17 metros, realizadas sobre essa unidade. A caracterização desses fósseis e a análise dos sedimentos e dos dados dos SPTs permitiu identificar depósitos de retrobarreira representando uma sequência retrogradacional caracterizada por fácies de fundo e margem lagunar sobrepostas por fácies eólicas arenosas, recobertas por depósitos de loess. A assembleia de fósseis, encontrada em depósitos de fundo e margem lagunar, é dominada por moluscos bivalves e gastrópodes, em sua maioria característicos de ambiente marinho franco raso (≤ 30 metros), mas também inclui alguns bivalves típicos de ambiente lagunar, como Erodona mactroides e Anomalocardia brasiliana A presença de espécies que não vivem atualmente nessa região sugere a influência de águas costeiras mais quentes durante o último estágio interglacial. O bom estado de preservação da maior parte da assembleia de moluscos, sem sinais de abrasão, bioerosão ou incrustação, indica curto tempo de residência na interface sedimento-água após a morte, seguido por rápido soterramento abaixo da Zona Tafonomicamente Ativa (TAZ). A presença de espécies marinhas juntamente com espécies de ambientes mixohalinos de baixa energia indica o transporte de sedimentos e fauna marinhos para a retrobarreira, o que teria ocorrido durante a fase transgressiva da evolução do Sistema III. Esse processo poderia estar relacionado ao aumento de tempestades durante o último interglacial, promovendo o transporte de grandes quantidades de sedimentos e conchas da face praial para a retrobarreira através de sobrelavagem da barreira (overwash) e abertura de inlets efêmeros.
The Barrier-Lagoon System III is the most preserved Pleistocene depositional system in the southern Coastal Plain of Rio Grande do Sul. The origin of this unit is correlated to the sea-level highstand of the last interglacial stage, but so far very little is known about the evolution and stratigraphy of this unit due to the scarcity of outcrops. A fossil assemblage consisting of thousands of bivalve and gastropod shells were recovered from drilling holes and SPT (Standard Penetration Test) surveys performed at depths up to 17 meters on that unit. The characterization of these fossils in addition to the analysis of the sediments and SPT data allowed to identify backbarrier deposits representing a retrogradational sequence characterized by lagoon bottom and margin facies superposed by sandy aeolian facies, covered by loess deposits. The fossil assemblage found in the lagoon bottom and margin deposits is dominated by bivalve and gastropod molluscs, mostly characteristic of open marine, shallow (≤ 30 meters) environment, but including some Erodona mactroides and Anomalocardia brasiliana, bivalves typical of lagoon environments The presence of species that do not currently live in the region suggests the influence of warmer coastal waters during the last interglacial stage. The good state of preservation of a large part of the molluscan assemblage, with no signs of abrasion, bioerosion or incrustation, indicates short residence time at the sediment-water interface after death, followed by rapid burial below the Taphonomically Active Zone (TAZ). The presence of marine species together with species from low energy mixohaline environments indicates the transport of sediments and marine fauna to the backbarrier, which would have occurred during the transgressive phase of the System III evolution. This process could have been related to increased storminess during the last interglacial, which promoted the transportation of large amounts of sediments and shells from the shoreface to the backbarrier through overwash and opening of ephemeral inlet channels.

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Salel, Tiphaine. "Dynamique des environnements fluvio-lagunaires du Narbonnais à l'Holocène (Golfe du Lion, France)." Thesis, Montpellier 3, 2018. http://www.theses.fr/2018MON30083.

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Le paysage littoral de la basse vallée de l’Aude est composé d’une mosaïque de milieux laguno-deltaïques mobiles à l’échelle des derniers millénaires. Du fait de cette mobilité et de l’ancienneté de l’occupation humaine, continue depuis le Néolithique, la compréhension des dynamiques environnementales passées constitue une problématique incontournable de la recherche archéologique narbonnaise. Le travail que nous présentons vise à identifier et expliquer les transformations de ce paysage fluvio-lagunaire à l’Holocène, à partir de l’analyse sédimentologique et micropaléontologique des enregistrements sédimentaires datés au radiocarbone. Dans un premier temps, une étude de la répartition spatiale actuelle des ostracodes des lagunes et embouchures fluviales modernes est proposée en vue d’utiliser cette microfaune comme bioindicateur privilégié des conditions environnementales passées dans la zone d’étude. Elle repose sur le prélèvement d’une soixantaine d’échantillons de sédiments de surface provenant de différents complexes paraliques de Méditerranée nord-occidentale. Les assemblages d’ostracodes actuels permettent de caractériser différents stades d’isolement des bassins, des lagunes complètement fermées jusqu’aux baies largement ouvertes sur la mer, ainsi que la variabilité intra-lagunaire des milieux en relation avec la proximité des embouchures et des graus. La base de données présentée peut être utilisée, à titre comparatif, pour reconstituer les dynamiques géomorphologiques littorales holocènes, telles que la mobilité deltaïque et l’évolution des systèmes barrières-lagunes, dans le golfe du Lion. Dans un second temps, l’étude des enregistrements sédimentaires a permis d’appréhender l’évolution du littoral narbonnais à l’Holocène. Elle repose sur neuf sondages carottés répartis sur les deux branches deltaïques, méridionale et orientale, de l’Aude. Les résultats obtenus permettent de proposer un scénario paléogéographique reconstituant la dynamique des environnements de la basse vallée depuis 9500 ans cal. BP, en même temps qu’ils renseignent le contexte local de la remontée du niveau marin holocène dans l’intervalle 9500-6000 ans cal. BP. Plusieurs problématiques sous-jacentes à l’évolution des paléoenvironnements littoraux narbonnais sont discutées. Elles concernent les modalités de la transgression holocène dans les lagunes du golfe du Lion, l’enregistrement d’un événement marin extrême en fond de ria vers 5200-5000 ans cal. BP, et le rythme de progradation accéléré du delta de l’Aude durant le dernier millénaire. L’identification de deux périodes d’enrichissement en plomb cohérentes avec les principaux pics d’exploitation minière connus en Languedoc à la charnière du changement d’ère et au début du Moyen-âge classique suggère un enregistrement de la fluctuation historique des activités métallurgiques
The present day Aude valley’s coastal landscape is the result of unstable lagoonal and deltaic environments during the last millennia. The understanding of past environmental dynamics is a key issue of the local ar-chaeological research, because since the Neolithic period human beings have settled in this area. This work aims to identify and explain the fluvio-lagoonal landscape’s evolution in the Narbonne region during the Holocene by using sedimentology, micropalaeontology and radiocarbon sediment datations. First, we analysed the present ostracods spatial distribution in modern lagoons and river mouths in order to use this microfauna as a bioindicator of past environmental conditions in the study area. Various aquatic envi-ronments (60) from the NW Mediterranean coastline were studied. The present ostracod assemblages characterize different stages of isolation, from completely closed lagoons to widely open marine bays, as well as intra-lagoonal environmental variability in relation to the inlets and river mouth proximities. The proposed database can be used to reconstruct coastal geomorphologies and dynamics, such as the holocene evolution of delta and barrier-lagoon systems in the Gulf of Lion. Second, sedimentary recording studies have been used to analyse the Narbonne’s coastal evolution. This study is based on nine cores distributed over the southern and eastern deltaic branches of the Aude river. With theses results, it is possible to propose a palaeogeographic scenario associated with the environmental dynamics of the lower valley since 9500 years cal. BP. This same data informs us about the local context of the Holocene sea level rise during the 9500-6000 years cal. BP. Several issues are discussed such as : the Holocene’s transgressions of the Gulf of Lion’s lagoons, the extreme marine event near the bay head delta around 5200-5000 years cal. BP, and the Aude delta’s rapid progradation during the last millennium. Additionally, we identified two periods of lead enrichment; which are consistent with the major mining peaks known in Languedoc (beginning of the first century AD - beginning of the classical Middle ages) and suggest a record of fluctuating metallurgical activity

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Yahyaoui, Ahlem. "Conflits d'usage environnementaux sur les rives de la lagune de Bizerte (Tunisie) : une mise en perspective méditerranéenne." Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0706/document.

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La thèse cherche à comprendre les significations socio-spatiales des dynamiques conflictuelles relatives à l'environnement en territoire lagunaire pour apprécier ses effets en termes de gouvernance environnementale. L'analyse porte sur les raisons et la genèse des oppositions d'acteurs à l'œuvre autour de la lagune de Bizerte (Tunisie) et de l’étang de Berre (Marseille). Mettre l’accent sur les conflits représente un enjeu pour la mise en place d’une gestion intégrée des zones humides. Ce sujet a été travaillé par d’autres chercheurs, cependant, il reste d’un intérêt majeur, d’une part, parce qu’il renforce la connaissance en la matière, et d’autre part, parce que le territoire étudié est original. La recherche pose plus particulièrement la question des éventuelles incidences que les conflits peuvent avoir sur les organisations et les institutions en place. L’action publique est-elle renouvelée suite à l’émergence ou à la régulation des conflits ? Ces questionnements se réfèrent à des enjeux de sociétés, actuels et majeurs, sur un territoire en mutation extrêmement rapide : la lagune de Bizerte, sur la rive Sud de la Méditerranée, dans un pays où le régime est en pleine transition. Cette recherche ouvre des perspectives dans l'étude du potentiel d'émergence de la démarche participative et de l'intégration sociale de la question environnementale sur des territoires littoraux, urbains ou ruraux
The dissertation seeks to recognize the socio-spatial meanings of dynamic conflicts related to the environment in the lagoon and to assess its effects in terms of environmental governance as well. The analysis concentrates on the reasons and the genesis of the actors’ oppositions at work around the lagoon of Bizerte (Tunisia) and the pond of Berre (Marseille). Putting the light on these conflicts represents an issue for the integrated wetland management. This topic has been tackled on by other researchers. However, it remains a major interest due to the knowledge and the originality of the territory. Particularly, the thesis raises the question of the potential impacts that conflicts can have on organizations and institutions in place. In fact, is it possible that public action will be renewed to follow the emergence or conflicts regulation? This question is tied to the challenges of the current and major companies and to an extreme rapidity of territory changing: Bizerte’s lagoon is situated on the southern shore of the Mediterranean and in a country where the regime is in continuous transition. This research covers the ground to study the potential emergence of the participative approach and the social integration of environmental issues in coastal, urban and rural territory

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Dissertations / Theses on the topic 'Coastal Lagoon'

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