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Sarango J., Douglas D. "ANALISIS DEL PROBLEMA DE INTRUSION MARINA DEL ACUIFERO DE CHILCA MEDIANTE MODELAMIENTO NUMERICO." Revista de Investigación de Física 9, no. 02 (December 29, 2006): 61–67. http://dx.doi.org/10.15381/rif.v9i02.8592.
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La presente investigación tiene como objetivo el análisis y la evaluación del problema actual de intrusión marina del acuífero de Chilca mediante la modelación númerica. Para cumplir con este objetivo es necesario contar con un manejo apropiado de este sistema acuífero y establecer politicas de operación, manejo y conservación, para lo cual se debe efectuar un estudio del comportamiento espacial y temporal de este recurso hídrico. En este sentido, se ha efectuado el modelamiento númerico del acuífero de Chilca en regimen permanente mediante la solución de las ecuaciones que gobiernan el flujo del agua subterránea en medios porosos, utilizandose para ello la técnica de elementos finitos con el uso de mallas triangulares desarrollado en el Modelo Micro-Fem V.3. Se genero 143 elementos triangulares y 100 nodos, asignando a cada elemento datos de piezometria, caudal de explotación, trasmisibilidad, etc. Con el modelo númerico calibrado se simulo las hipotesis de explotación futura plantedas por el sector agricultura, determinandose de esta forma la nueva posición del nivel del agua subterránea en el área del acuífero de Chilca. La ubicación de la interfase agua dulce – agua salada, que representa el problema de intrusión marina, fue determinada aplicando la condición de Ghyben-Herzberg a los resultados de los nuevos niveles del agua subterránea obtenidos al simular las hipotesis de explotación plantedas. Los resultados indican que en las zonas del valle de Chilca denominadas S2, S3, S4, S5 y S6 los pozos ubicados en ellas extraerian agua contaminada con alto contenido de cloruro de sodio. Mientras que la zona S1, solo podria ser explotada vía pozos para poder abastecer de agua potable a la ciudad de Chilca, ubicada a mitad del valle.
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Custodio, Emilio. "Consecuencias de la intrusión marina en la España mediterránea e insular según el informe SASMIE." BOLETÍN GEOLÓGICO Y MINERO 131, no. 4 (December 2020): 775–94. http://dx.doi.org/10.21701/bolgeomin.131.4.015.
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Nagaraju, Arveti, Arveti Thejaswi, and Yenamala Sreedhar. "Assessment of Groundwater Quality of Udayagiri area, Nellore District, Andhra Pradesh, South India Using Multivariate Statistical Techniques." Earth Sciences Research Journal 20, no. 4 (October 1, 2016): 1. http://dx.doi.org/10.15446/esrj.v20n4.54555.
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Hydrogeochemical studies were carried out in and around Udayagiri area of Andhra Pradesh in order to assess the chemistry of the groundwater and to identify the dominant hydrogeochemical processes and mechanisms responsible for the evolution of the chemical composition of the groundwater. Descriptive statistics, correlation matrices, principal component analysis (PCA), together with cluster analysis (CA) were used to gain an understanding of the hydrogeochemical processes in the study area. PCA has identified 4 main processes influencing the groundwater chemistry viz., mineral precipitation and dissolution, seawater intrusion, cation exchange, and carbonate balance. Further, three clusters C1, C2 and C3 were obtained. Samples from C1 contain high level of Cl− and may be due to the intensive evaporation and contamination from landfill leachate. Most of the samples from C2 are located closer to the sea and the high level of Na+ +K+ in these samples may be attributed to seawater intrusion. The geochemistry of water samples in C3 are more likely to originate from rock weathering. This has been supported by Gibbs diagram. The groundwater geochemistry in the study area is mostly of natural origin, but is influenced to some degree by human activity. Evaluación de la calidad del agua subterránea a través de técnicas estadísticas multivariadas en el área Udayagiri, distrito Nellore, Andhra Pradesh, en el sur de IndiaResumenSe realizaron estudios hidrogeoquímicos en y alrededor del área Udayagiri de Andhra Pradesh para evaluar la química del agua subterránea e identificar los procesos hidrogeoquímicos dominantes y los mecanismos responsables de la evolución en la composición química del agua subterránea. Se utilizaron estadísticas descriptivas, matrices de correlación, análisis de componentes principales, al igual que análisis de grupos, para obtener y entender los procesos hidrogeoquímicos en el área de estudio. Los análisis de componentes principales identificaron cuatro procesos determinantes que influenciaron la química del agua subterránea, estos son, la precipitación y disolución de minerales, l intrusión de agua marina, el intercambio de cationes y el equilibrio de carbonatos. De esta forma se obtuvieron tres grupos, C1, C2, y C3. Las muestras del grupo C1 contienen un alto nivel de Cl- , lo que podría deberse a la intensa evaporación y contaminación de los lixiviados de rellenos sanitarios. Muchas de las muestras del grupo C2 se ubican cerca del mar y el alto nivel de Na++K+ podría atriburise a la intrusión de agua marina. La geoquímica de las muestras de agua en el grupo C3 probablemente se desprende de la meteorización de rocas. El diagrama de Gibbs valida estos resultados. La geoquímica del agua subterránea en el área de estudio es principalmente de origen natural pero también está influenciado por la actividad humana en algún grado.
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Pino, Edwin, Lía Ramos, Oscar Avalos, Príncipe Tacora, Eduardo Chávarri, Oscar Angulo, David Ascensios, and Jesús Mejía. "Factores que inciden en el agotamiento y la contaminación por intrusión marina en el acuífero costero de La Yarada, Tacna, Perú." Tecnología y ciencias del agua 10, no. 5 (September 1, 2019): 177–213. http://dx.doi.org/10.24850/j-tyca-2019-05-07.
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Purca, Sara, and Aida Henostroza. "Presencia de microplásticos en cuatro playas arenosas de Perú." Revista Peruana de Biología 24, no. 1 (April 21, 2017): 101. http://dx.doi.org/10.15381/rpb.v24i1.12724.
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Se presenta el número y peso por metro cuadrado de fragmentos de microplásticos presentes en cuatro playas arenosas de la costa peruana. Las muestras fueron colectadas entre junio de 2014 y mayo 2015. Fragmentos de plástico duro mayores a 1 mm fueron encontrados en más del 80% de las muestras de las cuatro playas. La playa Costa Azul (~ 12°S) presentó 522 fragmentos por metro cuadrado (items/m2) de microplásticos, de los cuales, 463.33 items/m2 y 2.6 g/m2 fueron plásticos duros. La playa Albúfera de Medio Mundo (~ 11°S) presentó el menor número y peso de microplásticos (4.67 items/m2 y 0.50 g/m2). Una muestra aleatoria de la playa Costa Azul fue analizada por el espectroscopio FT-IR. Se encontró 5 fragmentos con poliuretano (PE), dos fragmentos con polipropileno (PP) y un fragmento con estireno (EPS). Pocos estudios mencionan al plástico duro como la mayor fracción de los microplásticos, se sugiere nuevas fuentes de intrusión y vías de microbasura en los hábitas, los cuales podrían estar afectando desde la base de trama trófica marina en el Perú.
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De Bustamante, Irene, Marco Cabrera, Lucila Candela, and Javier Lillo. "La reutilización de aguas regeneradas en España: ejemplos de aplicación en el marco del Proyecto Consolider-Tragua." Aqua-LAC 2, no. 1 (March 31, 2010): 01–17. http://dx.doi.org/10.29104/phi-aqualac/2010-v2-1-01.
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La reutilización de aguas depuradas en España se realiza desde hace décadas, siendo uno de los países en los que esta práctica está más extendida. Sin embargo, no se llega a reutilizar más del 5% del total de las aguas residuales recogidas, aunque en algunos casos, como en Canarias, el agua depurada ha llegado a suponer un 20% del agua consumida. En este artículo se presentan tres ejemplos de reutilización de aguas depuradas con una importante incidencia en los aspectos ambientales y asociados a condiciones hídricas diversas. Los estudios se están llevando a cabo dentro del Proyecto CONSOLIDER-TRAGUA cuyo objetivo es abordar de manera integrada los aspectos implicados en la reutilización de aguas residuales procedentes de las estaciones depuradoras de aguas residuales urbanas. Las zonas seleccionadas para los estudios de campo se sitúan en Andalucía donde el agua regenerada se aplica a filtros verdes y riego de cultivos para la obtención de biodiesel; Canarias para riego de campos de Golf y Cataluña donde el agua es inyectada para generar una barrera hidráulica contra la intrusión marina del acuífero. En los tres casos estudiados se incide en los aspectos suelo-agua-planta y sus impactos en el medio.
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Rojas Gonzáles, E., H. Herrera Pamo, and Douglas D. Sarango. "Desarrollo e implementación de un modelo matemático para la evaluación del impacto ambiental de la intrusión marina en el acuífero del rio Caplina, Tacna Perú." Revista de Investigación de Física 13, no. 01 (July 15, 2010): 1–9. http://dx.doi.org/10.15381/rif.v13i01.8922.
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La sobreexplotación de los acuíferos costeros de nuestro país para el abastecimiento de la demanda de agua para uso doméstico y agrícola ha producido en los últimos años un incremento del problema de la intrusión marina en estos acuíferos. Una forma de diagnosticar y diseñar la solución a este problema, es la modelación matemática en régimen transitorio; que consiste en la solución numérica de las ecuaciones que gobiernan el flujo de agua en un acuífero del rio Caplina en Tacna-Perú. En la etapa de calibración mensual del modelo, se logró reproducir el comportamiento del acuífero para el año 2000 con un 95% de aproximación; es decir un 5% de error entre las piezometrías históricas y las piezometrías obtenidas por el modelo desarrollado. Considerando el futuro incrementado del área agrícola para el periodo 2000-2004, se simularon dos caudales de explotación, que dan una nueva posición de la interface agua dulce-agua salada. Al simularse con el primer caudal de explotación, los resultados indican que no representa un peligro para la zona del litoral del valle del Caplina, mientras que al simularse con el segundo caudal de explotación los resultados indican que está en peligro la reserva de agua del acuífero.
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Delgado, Valeria, Heyddy Calderón, Yelba Flores, and Thelma Salvatierra. "Calidad y Disponibilidad de los Recursos Hídricos en tres Microcuencuas Costeras del Municipio de Tola, Nicaragua." Universidad y Ciencia 5, no. 8 (May 23, 2011): 13–21. http://dx.doi.org/10.5377/uyc.v5i8.314.
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Las actividades económicas, el crecimiento de la población en general; así como los cambios climáticos globales, han aumentado la presión sobre los recursos hídricos en el país. Esto se refleja tanto en una disminución en la disponibilidad, así como en la pérdida de calidad de estos recursos. En consecuencia, los gobiernos municipales han formado alianzas estratégicas con organismos internacionales e instituciones académicas para producir información base necesaria para la creación y ejecución de planes de ordenamiento territorial, a fin de planificar futuras demandas de agua. El desarrollo turístico en la franja costera del Municipio de Tola ha generado cambios en el uso del suelo, desprotección de las zonas de recarga de los acuíferos, posible riesgo de intrusión marina por el bombeo excesivo en la zona costera, y ha creado problemas con la disposición de residuos sólidos. Los resultados indican que hay disponibilidad de agua, tanto superficial como subterránea en las tres microcuencas costeras estudiadas; sin embargo su calidad se ha afectado por la presencia de heces fecales en las aguas de los pozos y por residuos de carbamatos en los ríos. El Índice Biótico de Familias de Hilsenhoff arrojó que el agua es relativamente mala en la parte alta y media de las 3 microcuencas. Fue identificada una especie nueva para el Pacífico Sur de Nicaragua (Theodoxus sp.) y una reportada por primera vez en 1972 en San Juan del Sur (Trinectes fonsecensis). Aunque el agua está disponible en cantidad, su calidad restringe su uso para consumo humano; por lo que es necesario concientizar a la población del municipio en cuanto a la protección, limpieza y uso adecuado de los recursos hídricos.DOI: http://dx.doi.org/10.5377/uyc.v5i8.314Universidad y Ciencia No 8 Año 5 2010 13-21
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Gandhi, S. S., J. K. Mortensen, N. Prasad, and O. van Breemen. "Magmatic evolution of the southern Great Bear continental arc, northwestern Canadian Shield: geochronological constraints." Canadian Journal of Earth Sciences 38, no. 5 (May 1, 2001): 767–85. http://dx.doi.org/10.1139/e00-094.
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The calc-alkaline Great Bear continental arc in the Wopmay Orogen developed after a collision ca. 1890 Ma of the Archean Slave craton with the Paleoproterozoic Hottah terrane to the west. UPb zircon dating of three volcanic and six intrusive rocks from the southern part of the arc shows four stages of development: (i) intrusion of a few small sodic leucogranite plutons at 1873 ± 2 Ma into a previously folded metasedimentary sequence; (ii) abundant calc-alkaline felsic volcanism and subvolcanic intrusions during the period 18701866 Ma, bracketed by five ages; (iii) intrusion of large calc-alkaline granitic plutons, including the Marian River batholith, dated by zircon and titanite from two samples at 1866 +23 Ma; and (iv) emplacement of the potassic Faber Lake rapakivi granite at 1856 +23 Ma. The arc was developed on the Hottah terrane due to easterly subduction of an oceanic plate under the amalgamated Slave craton Hottah terrane. The oldest exposed rocks in the southern part of the arc are remnants of a Paleoproterozoic platformal sequence. They were regarded previously as equivalents of the initial passive margin sequence on the Slave craton, but are interpreted here as part of the Hottah terrane. The ages reported here are comparable with earlier data from the northern part of the arc, which show an age range from 1875 to 1840 Ma and also identify two suites of compositionally and temporally distinct granites. The age constraints show that the Great Bear arc evolved rapidly in time from sodic through calc-alkaline, and then, with a pause, to potassic composition.
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Passow, Uta, and Edward B. Overton. "The Complexity of Spills: The Fate of the Deepwater Horizon Oil." Annual Review of Marine Science 13, no. 1 (January 3, 2021): 109–36. http://dx.doi.org/10.1146/annurev-marine-032320-095153.
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The Deepwater Horizon oil spill was the largest, longest-lasting, and deepest oil accident to date in US waters. As oil and natural gas jetted from release points at 1,500-m depth in the northern Gulf of Mexico, entrainment of the surrounding ocean water into a buoyant plume, rich in soluble hydrocarbons and dispersed microdroplets of oil, created a deep (1,000-m) intrusion layer. Larger droplets of liquid oil rose to the surface, forming a slick of mostly insoluble, hydrocarbon-type compounds. A variety of physical, chemical, and biological mechanisms helped to transform, remove, and redisperse the oil and gas that was released. Biodegradation removed up to 60% of the oil in the intrusion layer but was less efficient in the surface slick, due to nutrient limitation. Photochemical processes altered up to 50% (by mass) of the floating oil. The surface oil expression changed daily due to wind and currents, whereas the intrusion layer flowed southwestward. A portion of the weathered surface oil stranded along shorelines. Oil from both surface and intrusion layers were deposited onto the seafloor via sinking marine oil snow. The biodegradation rates of stranded or sedimented oil were low, with resuspension and redistribution transiently increasing biodegradation. The subsequent research efforts increased our understanding of the fate of spilled oil immensely, with novel insights focusing on the importance of photooxidation, the microbial communities driving biodegradation, and the formation of marine oil snow that transports oil to the seafloor.
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Banta, Robert M., Yelena L. Pichugina, W. Alan Brewer, Aditya Choukulkar, Kathleen O. Lantz, Joseph B. Olson, Jaymes Kenyon, et al. "Characterizing NWP Model Errors Using Doppler-Lidar Measurements of Recurrent Regional Diurnal Flows: Marine-Air Intrusions into the Columbia River Basin." Monthly Weather Review 148, no. 3 (February 10, 2020): 929–53. http://dx.doi.org/10.1175/mwr-d-19-0188.1.
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Abstract Ground-based Doppler-lidar instrumentation provides atmospheric wind data at dramatically improved accuracies and spatial/temporal resolutions. These capabilities have provided new insights into atmospheric flow phenomena, but they also should have a strong role in NWP model improvement. Insight into the nature of model errors can be gained by studying recurrent atmospheric flows, here a regional summertime diurnal sea breeze and subsequent marine-air intrusion into the arid interior of Oregon–Washington, where these winds are an important wind-energy resource. These marine intrusions were sampled by three scanning Doppler lidars in the Columbia River basin as part of the Second Wind Forecast Improvement Project (WFIP2), using data from summer 2016. Lidar time–height cross sections of wind speed identified 8 days when the diurnal flow cycle (peak wind speeds at midnight, afternoon minima) was obvious and strong. The 8-day composite time–height cross sections of lidar wind speeds are used to validate those generated by the operational NCEP–HRRR model. HRRR simulated the diurnal wind cycle, but produced errors in the timing of onset and significant errors due to a premature nighttime demise of the intrusion flow, producing low-bias errors of 6 m s−1. Day-to-day and in the composite, whenever a marine intrusion occurred, HRRR made these same errors. The errors occurred under a range of gradient wind conditions indicating that they resulted from the misrepresentation of physical processes within a limited region around the measurement locations. Because of their generation within a limited geographical area, field measurement programs can be designed to find and address the sources of these NWP errors.
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Casella, Daniele, Marco Meloni, Anne A. Petrenko, Andrea M. Doglioli, and Jerome Bouffard. "Coastal Current Intrusions from Satellite Altimetry." Remote Sensing 12, no. 22 (November 10, 2020): 3686. http://dx.doi.org/10.3390/rs12223686.
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The use of satellite-based data in coastal regions for the monitoring of fine-scale ocean dynamics, impacting marine ecosystems, is a difficult challenge. A random forest algorithm to detect slope current intrusions into the Gulf of Lion, Mediterranean Sea, has been developed using both improved coastal altimetry data and 10 year-long numerical simulations. The results have been compared to an independent dataset of in situ measurements from a bottom-moored Acoustic Doppler Current Profiler. The algorithm results are very promising: 93% of slope current intrusions have been correctly identified, and the number of false alarms is moderate. The dependence of the algorithm on several environmental factors is discussed in the paper. From the oceanographic point of view, our results confirm the strong impacts of horizontal winds in the dynamic of the intrusion events in the study area. Our methodology combining numerical modeling, in situ data and new machine-learning tools proves effective in improving the capabilities of ocean remote sensing in coastal areas.
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PEDERSEN, O., T. BINZER, and J. BORUM. "Sulphide intrusion in eelgrass (Zostera marina L.)." Plant, Cell and Environment 27, no. 5 (May 2004): 595–602. http://dx.doi.org/10.1111/j.1365-3040.2004.01173.x.
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Talbot, C. J., and V. Von Brunn. "Intrusive and extrusive (micro)melange couplets as distal effects of tidal pumping by a marine ice sheet." Geological Magazine 124, no. 6 (November 1987): 513–25. http://dx.doi.org/10.1017/s0016756800017350.
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AbstractMicroscopic soft-sediment deformation structures in a 30 × 25 × 12 mm hand specimen of glaciogenic silty mudstone from the Permo-Carboniferous Dwyka Formation of northern Natal in South Africa are illustrated by serial sections. The processes these structures imply are interpreted using palinspastically restored sections and isopachytes reconstructed from them. The sedimentation of silts, muds, and microrhythmites is found to have been punctuated by episodes of hydraulic activity which resulted in thirteen bodies with the mixed fabrics of micromelanges. These are divisible into five melange types: (1) subconcordant intrusive; (2) disconcordant intrusive; (3) subconcordant extrusive; (4) near-surface with asymmetric internal structures, and (5) conformable near-surface with internal structures symmetric about the palaeovertical.Remarkable similarities between isopachs for pairs of micromelanges at different levels in the specimen suggest that intrusive melanges at depth fed contemporaneous extrusive melanges on the sea floor. Each couplet of melanges with matched isopachs is linked by faults which are interpreted as having acted as hydraulic vents despite only parts of them being infilled by intrusive melange. A significant proportion of the succession could consist of sediment recycled from depth by hydraulic extrusion. Repeated hydraulic intrusions along, and extrusions from, the same disturbed interface suggest that this interface acted as the distal leaking end of one of the hydraulic sills recently described by von Brunn & Talbot (1986). Pulses of pressurized water were transmitted through a prograding marine slope of quickclay by the tidal pumping of a marine ice sheet periodically grounding upslope.The results of this analysis are extrapolated to processes operative in subduction complexes. All four fabrics described from large-scale hydraulic melanges in modern and ancient accretionary prisms are matched on a much smaller scale in our sample from a proglacial submarine slope. Dismemberment by faults is the only fabric element described from accretionary complexes which is missing from the micro-analogues described here.
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Shannon, N. R., P. A. Mackinnon, and G. Hamill. "Modelling of saline intrusion in marine outfalls." Proceedings of the Institution of Civil Engineers - Maritime Engineering 158, no. 2 (June 2005): 47–58. http://dx.doi.org/10.1680/maen.2005.158.2.47.
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Hasler-Sheetal, Harald, and Marianne Holmer. "Sulfide Intrusion and Detoxification in the Seagrass Zostera marina." PLOS ONE 10, no. 6 (June 1, 2015): e0129136. http://dx.doi.org/10.1371/journal.pone.0129136.
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Pulido Bosch, A., F. Navarrete, L. Molina, and J. L. Martinez-Vidal. "Quantity and Quality of Groundwater in the Campo De Dalias (Almeria, Se Spain)." Water Science and Technology 24, no. 11 (December 1, 1991): 87–96. http://dx.doi.org/10.2166/wst.1991.0340.
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The Campo de Dalías is the most economically important agricultural area in the whole of the Province of Almeria. A benign climate combined with the expertise of the market gardeners and their intensive cultivation in plastic hot-houses of out-of-season fruit and vegetables has turned a stony wasteland into an area of great productivity. The main water supply comes from a series of wells drilled into the subterranean aquifers running through the local rocks, a geometrically complex succession of Triassic limestones and dolomites, Miocene conglomerates and calcareous sandstones, Pliocene calcarenites and Quaternary gravels, sands and silts. The annual influx into the aquifers has been calculated as being around 50 Hm3, while at the present day more than 100 Hm3 are being taken out during the same period. This over exploitation of the resources is causing an inexorable descent in the water table, which is leading to marine intrusion in those aquifers nearest the sea. The main aquifer-bearing units are Balanegra and Aguadulce, composed essentially of Triassic, Alpujarride carbonates, and the Balerma-Las Marinas unit, made, up of Pliocene calcarenites. In the water from some of the wells in the Aguadulce unit more than 10,000 microS/cm have been measured at some distance from the coast, while in the Balanegra unit there are a large number of conoids below sea level, although marine intrusion is at present limited to a fairly narrow coastal strip.
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Marjoua, A., P. Olive, and C. Jusserand. "Apports des outils chiniques et isotopiques à l'identification des origines de la salinisation des eaux : Cas de la nappe de La Chaouia côtière (Maroc)." Revue des sciences de l'eau 10, no. 4 (April 12, 2005): 489–505. http://dx.doi.org/10.7202/705290ar.
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L'étude hydrochimique des eaux de la nappe libre de la Chaouia côtière montre une teneur excessive en sels dans ces eaux, spécialement des chlorures (jusqu'à 3 g.l-1).Cette salinité élevée peut, à terme, nuire gravement à l'économie de la région qui se consacre essentiellement à la culture maraîchère sous irrigation. Des mesures isotopiques (18O/16O, 2H/1H) couplées aux éléments chimiques, notamment Br-/Cl-, excluent l'hypothèse d'une intrusion marine généralisée. L'existence d'une paléosalinité (SHIVANNA andal.,1993) n'est pas soutenue par les mesures des teneurs en isotopes radioactifs (3H, 14C). Il en est de même pour le lessivage de dépôts chlorurés préexistants dans les sédiments. L'apport essentiel en chlorures provient de l'altération de la roche mère, des fertilisants et des embruns marins lessivés par suite de l'irrigation et entraînés vers la nappe par percolation. Le recyclage de l'eau souterraine depuis au moins trente ans, par l'irrigation, n'a fait qu'augmenter cette salinité. Toutefois en bordure de l'océan quelques puits semblent montrer la présence d'eau marine, en effet les débits d'exhaure des puits sont à la limite d'exploitation de la nappe et toute augmentation de débits dans ces puits engendrera fatalement une invasion marine généralisée.
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Li, Xin. "Collaborative Intrusion Detection Method for Marine Distributed Network." Journal of Coastal Research 83, sp1 (May 4, 2019): 57. http://dx.doi.org/10.2112/si83-010.1.
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Skulski, Thomas, Robert P. Wares, and Alan D. Smith. "Early Proterozoic (1.88–1.87 Ga) tholeiitic magmatism in the New Québec orogen." Canadian Journal of Earth Sciences 30, no. 7 (July 1, 1993): 1505–20. http://dx.doi.org/10.1139/e93-129.
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The New Québec orogen contains two volcano-sedimentary sequences bounded by unconformities. Each sequence records a change from continental sedimentation and alkaline volcanism to marine sedimentation and tholeiitic volcanism. The first sequence records 2.17 Ga rifting and the development, by 2.14 Ga, of a passive margin along the eastern part of the Superior craton. The second sequence developed between 1.88 and 1.87 Ga in pull-apart basins that reflect precollisional dextral transtension along the continental margin. Second-sequence magmatism comprises (i) carbonatitic and lamprophyric intrusions and mildly alkaline mafic to felsic volcanic rocks; (ii) widespread intrusion of tholeiitic gabbro sills, and submarine extrusion of plagioclase glomeroporphyritic basalts and younger aphyric basalts and picrites; and (iii) late-stage, mafic to felsic volcanism and intrusion of carbonatites. Crustal thinning allowed primitive tholeiitic magmas to equilibrate at progressively lower pressures before more buoyant derivative liquids could erupt. Early primitive melts were trapped at the base of the crust and crystallized olivine and orthopyroxene with minor crustal contamination. Derivative melts, similar to transitional mid-ocean-ridge basalts, migrated upward into mid-crustal magma chambers where they became saturated in calcic plagioclase. Subsequent tapping of these magma chambers allowed plagioclase ultraphyric magmas to intrude the sedimentary pile and erupt on the sea floor. Prolonged lithospheric extension resulted in more voluminous mantle melting and eruption of picrites and basalts in the south. Primitive magmas in the north were trapped beneath thicker crust and crystallized wehrlite cumulates. Resulting basaltic melts intruded the volcano-sedimentary pile, or erupted as aphyric basalts.
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Smith, R. A., D. Stephenson, and S. K. Monro. "The geological setting of the southern Bathgate Hills, West Lothian, Scotland." Earth and Environmental Science Transactions of the Royal Society of Edinburgh 84, no. 3-4 (1993): 189–96. http://dx.doi.org/10.1017/s026359330000599x.
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ABSTRACTThe southern Bathgate Hills, in the eastern part of the Midland Valley basin of Scotland, were the site of a volcanic rise during late Dinantian to early Silesian times and a sequence of basaltic lavas and tuffs up to 600 m thick accumulated. The volcanic pile interrupted the regional sedimentary deposition, which involved a cyclical sequence of marine limestones and mudstones followed by estuarine, lagoonal and deltaic clastic deposits. During the Brigantian Stage of the Dinantian, freshwater terrestrial environments developed locally on the volcanic rise between eruptive phases, but later in the Brigantian the rise was transgressed by marine limestones. Intermittent basaltic eruptions continued into the Amsbergian Stage of the Silesian, accompanied by intrusion of high-level alkaline doleritic sills and associated with strata-bound Zn—Pb mineralisation. Folding later in the Silesian was followed by the intrusion of a suite of quartz-dolerite sills and dykes. These latter were commonly intruded along penecontemporaneous E—W trending faults. The intrusion of the quartz-dolerites may have resulted in remobilisation of earlier strata-bound mineralisation into epigenetic veins.
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Tan, Shi Zhe, and Sheng Xu Wang. "Digital Holographic Imaging of Marine Plankton." Applied Mechanics and Materials 198-199 (September 2012): 314–19. http://dx.doi.org/10.4028/www.scientific.net/amm.198-199.314.
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Designing an advanced method to sensing marine plankton effectively is highly demanded for acquiring critical marine plankton information data. The goal of this paper is to use digital holographic imaging for sensing marine plankton in recording sampling volume with several advantages such as non-intrusive and non-destructive interrogation of the recording sampling volume. So, by capturing hologram of marine plankton and reconstructing hologram, the recorded optical field of marine plankton is retrieved.
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Talke, Stefan A., and David A. Jay. "Changing Tides: The Role of Natural and Anthropogenic Factors." Annual Review of Marine Science 12, no. 1 (January 3, 2020): 121–51. http://dx.doi.org/10.1146/annurev-marine-010419-010727.
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Tides are changing worldwide at rates not explained by astronomical forcing. Rather, the observed evolution of tides and other long waves, such as storm surges, is influenced by shelf processes and changes to the roughness, depth, width, and length of embayments, estuaries, and tidal rivers. In this review, we focus on processes in estuaries and tidal rivers, because that is where the largest changes to tidal properties are occurring. Recent literature shows that changes in tidal amplitude have been ubiquitous worldwide over the past century, often in response to wetland reclamation, channel dredging, and other environmental changes. While tidal amplitude changes are sometimes slight (<1%) or even negative, we identify two types of systems that are particularly prone to tidal amplification: ( a) shallow, strongly damped systems, in which a small increase in depth produces a large decrease in effective friction, and ( b) systems in which wave reflection and resonance are strongly influenced by changes to depth, friction, and convergence. The largest changes in amplitude occur inland, some distance from the coast, and can sometimes be measured in meters. Tide changes are a leading indicator that the dynamics of storm surges and river flood waves have also changed and are often associated with shifts in sediment transport, salinity intrusion, and ecosystem properties. Therefore, the dynamics of tidal evolution have major implications for coastal management, particularly for systems that are sensitive to changes in geometry induced by sea-level rise and anthropogenic development.
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Walsh, Gregory J., John N. Aleinikoff, Robert A. Ayuso, and Robert P. Wintsch. "Age and tectonic setting of the Quinebaug-Marlboro belt and implications for the history of Ganderian crustal fragments in southeastern New England, USA." Geosphere 17, no. 4 (June 21, 2021): 1038–100. http://dx.doi.org/10.1130/ges02295.1.
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Abstract Crustal fragments underlain by high-grade rocks represent a challenge to plate reconstructions, and integrated mapping, geochronology, and geochemistry enable the unravelling of the temporal and spatial history of exotic crustal blocks. The Quinebaug-Marlboro belt (QMB) is an enigmatic fragment on the trailing edge of the peri-Gondwanan Ganderian margin of southeastern New England. SHRIMP U-Pb geochronology and geochemistry indicate the presence of Ediacaran to Cambrian metamorphosed volcanic and intrusive rocks dated for the first time between ca. 540–500 Ma. The entire belt may preserve a cryptic, internal stratigraphy that is truncated by subsequent faulting. Detrital zircons from metapelite in the overlying Nashoba and Tatnic Hill Formations indicate deposition between ca. 485–435 Ma, with provenance from the underlying QMB or Ganderian crust. The Preston Gabbro (418 ± 3 Ma) provides a minimum age for the QMB. Mafic rocks are tholeiitic with trace elements that resemble arc and E-MORB sources, and samples with negative Nb-Ta anomalies are similar to arc-like rocks, but others show no negative Nb-Ta anomaly and are similar to rocks from E-MORB to OIB or backarc settings. Geochemistry points to a mixture of sources that include both mantle and continental crust. Metamorphic zircon, monazite, and titanite ages range from 400 to 305 Ma and intrusion of granitoids and migmatization occurred between 410 and 325 Ma. Age and chemistry support correlations with the Ellsworth terrane in Maine and the Penobscot arc and backarc system in Maritime Canada. The arc-rifting zone where the Mariana arc and the Mariana backarc basin converge is a possible modern analog.
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Sin, Eunchong, In-Young Ahn, Seojeong Park, and Taewon Kim. "Effects of Low pH and Low Salinity Induced by Meltwater Inflow on the Behavior and Physical Condition of the Antarctic Limpet, Nacella concinna." Journal of Marine Science and Engineering 8, no. 10 (October 20, 2020): 822. http://dx.doi.org/10.3390/jmse8100822.
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Seawater acidification and freshening in the intertidal zone of Marian Cove, Antarctica, which occurs by the freshwater inflow from snow fields and glaciers, could affect the physiology and behavior of intertidal marine organisms. In this study, we exposed Antarctic limpets, Nacella concinna, to two different pH (8.00 and 7.55) and salinity (34.0 and 27.0 psu) levels and measured their righting ability after being flipped over, mortality, condition factor, and shell dissolution. During the 35-day exposure, there was no significant difference in behavior and mortality between different treatments. However, the condition factor was negatively affected by low salinity. Both low pH and low salinity negatively influenced shell formation by decreasing the aragonite saturation state (Ωarg) and enhancing shell dissolution. Our results suggest that, though limpets can tolerate short-term low pH and salinity conditions, intrusions of meltwater accompanied by the glacial retreat may act as a serious threat to the population of N. concinna.
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Przewłócka, Maria, Beata Jaworska-Szulc, Bohdan Kozerski, Małgorzata Pruszkowska-Caceres, Adam Szymkiewicz, and Andrzej Kwaterkiewicz. "Freshening of salinized groundwater in Gdańsk Quaternary aquifer." E3S Web of Conferences 54 (2018): 00025. http://dx.doi.org/10.1051/e3sconf/20185400025.
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The main Quaternary aquifer in the Gdańsk region connects directly with salt waters of the Martwa Wisła River and the Gulf of Gdańsk. This aquifer has been used for many years by large municipal and industrial intakes located on the marine lowlands, with maximum output 6236 m3/h in 1985. Owing to an intensive exploitation, groundwater in the area of the Old Gdańsk has been salinized by intrusion of salt water from the Martwa Wisła River. Concentration of chlorides in some wells reached 2000-3000 mgCl/dm3, leading to degradation of groundwater resources in this area. As a consequence the “Grodza Kamienna” groundwater intake had to be put out of operation. Salt water intrusion from the Gulf of Gdańsk was provoked in 1970s and 1980s by overexploitation of groundwater resources by three municipal intakes situated on the marine terrace. Concentration of chlorides in some piezometers of the “Czarny Dwór” groundwater intake amounted to 700 – 1000 mgCl/dm3, however in the pumping wells of the intake it never exceeded the drinking water standards. In 1990s groundwater pumping rates in both areas were lowered. As a result, the chloride concentration decreased and the resources started to recover. Current observations prove that groundwater of the main Quaternary aquifer is freshening and salt water intrusion has stopped. However, elevated concentrations of chlorides are observed in the shallow aquifer, due to anthropopressure.
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Loncarevic, B. D., Tomas Feininger, and Denis Lefebvre. "The Sept-îles layered mafic intrusion: geophysical expression." Canadian Journal of Earth Sciences 27, no. 4 (April 1, 1990): 501–12. http://dx.doi.org/10.1139/e90-046.
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Eighty-eight percent of the Cambrian Sept-Îles layered mafic intrusion, possibly the second largest on Earth, lies under the estuary of the St. Lawrence River. A marine geophysical cruise in 1986 tied together all earlier gravity surveys and added gravity measurements along 1100 km of new track lines.The following results were based on the 1986 survey and other geophysical data. The Sept-Îles layered mafic intrusion is nearly circular in plan and about 80 km in diameter. It is funnel shaped and some 5.6 km thick at its centre. It has a volume of about 20 000 km3 and is composed of gabbro and allied rocks in a layered series (nearly [Formula: see text] of the total bulk), ultramafic rocks in a lower series (about [Formula: see text]), and gabbro, anorthosite, and potassium-feldspar-bearing rocks in a transitional and upper series (about [Formula: see text]). Roof rocks on the intrusion may have been restricted to a consanguineous volcanic cap.The Sept-Îles intrusion is located at the northwestern end of a reentrant of the North American continent where Appalachian tectonostratigraphic zones are offset dextrally by 400 km. Emplacement of the intrusion may be related to the initial opening of Iapetus. The southeastern border of the intrusion is downwarped and overlain by a rocky cover 8 km thick. The cover may be composed of Taconian nappes thrust northwestward at the reclosing of Iapetus. If this is so, Logan's line crosses the Sept-Îles layered mafic intrusion about 10 km southeast of its centre.
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Sun, Bao Nan, Zhan Lian, and Yong Zeng Yang. "On Theoretical Models for Oil Droplets Size Distribution under the Influence of Surface Wave Breaking." Advanced Materials Research 998-999 (July 2014): 511–17. http://dx.doi.org/10.4028/www.scientific.net/amr.998-999.511.
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Marine oil spill often forms oil droplets in stormy conditions. Based on the dimensional analysis Rayleigh method, the relationship is established between entrainment rate of oil droplets and statistical physical quantities such as the energy dissipation rate, intrusion depth et al. An expression of size spectrum of oil droplets is derived based on theorem and relationship between the capillary number, the dimensionless intrusion time and viscosity ratio. Preliminary results show that the slope of the derived spectrum is-2.29, which agrees well with the measured slope-2.3 in laboratory. Shear rate, surface tension, droplet radius, oil and water viscosity is the main factors controlling the total number of the oil droplets.
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Darlan, Yudi, and Udaya Kamiludin. "RONA LINGKUNGAN GEOLOGI KELAUTAN DI PERAIRAN P. ROTE NUSA TENGGARA TIMUR." JURNAL GEOLOGI KELAUTAN 11, no. 3 (February 16, 2016): 149. http://dx.doi.org/10.32693/jgk.11.3.2013.239.
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Sejalan dengan perubahan Pulau Rote dari Pemerintahan Kecamatan menjadi Kabupaten, pembangunan infrastruktur pesisir dan sektor lainnya di pulau ini meningkat. Pembangunan tersebut dari tahun ke tahun dapat menimbulkan perubahan kondisi lingkungan pesisir dan perairan Pulau Rote. Perubahan kondisi lingkungan dapat diidentifikasi melalui analisis data rona lingkungan. Data seismik memperlihatkan morfologi teras-teras pantai, dan intrusi diapir serpih di perairan Pulau Rote yang mengiindikasikan pulau ini mengalami proses pengangkatan sejak ribuan tahun yang lalu hingga sekarang. Sedimen permukaan dasar laut Pulau Rote terdiri atas pasir dan pasir lanauan mengandung mineral kuarsa, piroksen, mineral karbonatan dan cangkang moluska menunjukkan kondisi lingkungan sedimentasi rendah. Baku Mutu air dan sedimen permukaan dasar laut di perairan Pulau Rote dalam kondisi baik. Jenis pantainya berupa pantai berenergi tinggi, pantai erosi, pantai teluk, dan pantai kantong pasir masih dalam kondisi baik dan cukup bagus bagi wisata pantai dan laut. Hasil penelitian ini menunjukkan sebagain besar kondisi lingkungan perairan Pulau Rote masih dalam kondisi baik. Sebagian kecil ada perubahan sebagai dampak aktivitas manusia.
Kata kunci: rona lingkungan, geologi kelautan, intrusi, diapir serpih, Nusa Tenggara Timur, Pulau Rote
Since the Rote Island government changed from the Kecamatan to Kabupaten Government, the development of coastal infrastructures and other sectors in the island increased. The development from time to time can lead to changes in coastal and marine environmental of the Rote Island. The environmental conditions can be identified through analysis environmental base data. The seismic data shows the morphology of coastal terraces, and intrusion of shale diapir in the Rote Island waters which indicate that this island has uplifted since thousands years ago until now. Surficial sediment of the Rote Island waters consists of sand and silty sand containing quartz and pyroxene minerals, and shells of mollusks which indicate low sedimentation environment. The standard quality of surface water and surficial sediment of the Rote Island is still in good condition. Coastal characteristics of this island consist of high-energy beaches, sand pocket beaches, bays, and erosion coasts which are still in good condition and suitable for tourism. This study shows that in general the environment of the Rote Island waters environment is normal conditions. A few of environmental changes is as an impact of human activities.
Keywords: environment features, intrusion, shale diapir, Nusa Tenggara Timur, Rote island.
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Soler, A., F. Torrella, J. Sáez, I. Martínez, J. Nicolás, M. Llorens, and J. Torres. "Performance of two municipal sewage stabilization pond systems with high and low loading in South-eastern Spain." Water Science and Technology 31, no. 12 (June 1, 1995): 81–90. http://dx.doi.org/10.2166/wst.1995.0463.
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From January to December 1992, the efficiency of two waste stabilization pond systems (WSPS) located in the Region of Murcia, South-eastern Spain, has been studied in terms of the physicochemistry and the microbiology of the systems. The efficiencies of the different stages of the treatment and the global performance have been compared. The WSPS of Lorquí and Ceutí (12,000 inhabitants) receives fruit processing and cannery wastes mixed with the urban sewage. This increases the load up to 95,000 equivalent inhabitants with an average BOD5 of 800 mgO2/l. Global reductions of COD and BOD5 were 79% and 73% as a yearly average. The mean of the reductions of indicator microorganisms were: coliphages (CHP), 83.14%; total coliforms (TC), 72.90%; faecal coliforms (FC), 93.84% and salmonellae (SAL), 98.29%. The WSPS of San Javier (15,000 inhabitants), situated at the border of the Mediterranean, does not receive industrial wastes but suffers from intrusions of marine waters into the sewers. BOD5 is diluted by the intrusion to less than 100 mgO2/l, even in summertime when population doubles because of the tourism. Average yearly reductions of COD and BOD5 were 32% and 21%. The means of the microbiological reductions were: CHP, 81.60%; TC, 90.77%; FC, 94.37% and SAL, 99.42%. Design constants have been calculated for both systems considering the climatic conditions of the area.
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Saaidia, Bachir, Mohamed Mahia, and Salah Chaab. "Identification of marine intrusion in the plain of Collo, northeastern Algeria." Journal of Water and Land Development 35, no. 1 (December 1, 2017): 211–19. http://dx.doi.org/10.1515/jwld-2017-0086.
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AbstractThe population increase, urbanization and intensification of agriculture and demands for water supply in the coastal plain of Collo led to excessive pumping of the unconfined aquifer with limited dimensions. This study aimed to characterize the effect of the overexploitation of the groundwater from the only unconfined aquifer in the region, what resulted in the inversion of the groundwater flow and the rise the possible seawater pollution that is shown in the water table map. The causes and effects of the saltwater intrusion were discussed. The interpretation of the electrical conductivity measurements, chloride and sodium maps have shown clearly the areas where values were the highest with tighter curves towards the sea, the wadis Guebli and Cherka. These values distribution indicated a marine source of salinity in wells and boreholes close to the sea and wadis.
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Terracciano, D. S., L. Bazzarello, A. Caiti, R. Costanzi, and V. Manzari. "Marine Robots for Underwater Surveillance." Current Robotics Reports 1, no. 4 (August 27, 2020): 159–67. http://dx.doi.org/10.1007/s43154-020-00028-z.
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Abstract Purpose of Review The paper reviews the role of marine robots, in particular unmanned vehicles, in underwater surveillance, i.e. the control and monitoring of an area of competence aimed at identifying potential threats in support of homeland defence, antiterrorism, force protection and Explosive Ordnance Disposal (EOD). Recent Findings The paper explores separately robotic missions for identification and classification of threats lying on the seabed (e.g. EOD) and anti-intrusion robotic systems. The current main scientific challenge is identified in terms of enhancing autonomy and team/swarm mission capabilities by improving interoperability among robotic vehicles and providing communication networking capabilities, a non-trivial task, giving the severe limitations in bandwidth and latency of acoustic underwater messaging. Summary The work is intended to be a critical guide to the recent prolific bibliography on the topic, providing pointers to the main recent advancements in the field, and to give also a set of references in terms of mission and stakeholders’ requirements (port authorities, coastal guards, navies).
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Peterson, A. Townsend, Adolfo G. Navarro-Sigüenza, and Xingong Li. "Joint Effects of Marine Intrusion and Climate Change on the Mexican Avifauna." Annals of the Association of American Geographers 100, no. 4 (August 31, 2010): 908–16. http://dx.doi.org/10.1080/00045608.2010.497351.
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Rozycki, Alexander. "Analysis of a Marine Intrusion by Parameters Derived from Salt-Water Conductivity." Ground Water 34, no. 6 (November 1996): 1076–81. http://dx.doi.org/10.1111/j.1745-6584.1996.tb02173.x.
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Nicolas, Julien P., and David H. Bromwich. "Climate of West Antarctica and Influence of Marine Air Intrusions*." Journal of Climate 24, no. 1 (January 1, 2011): 49–67. http://dx.doi.org/10.1175/2010jcli3522.1.
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Abstract High-resolution numerical weather forecasts from the Antarctic Mesoscale Prediction System (AMPS) archive are used to investigate the climate of West Antarctica (WA) during 2006–07. A comparison with observations from West Antarctic automatic weather stations confirms the skill of the model at simulating near-surface variables. AMPS cloud cover is also compared with estimates of monthly cloud fractions over Antarctica derived from spaceborne lidar measurements, revealing close agreement between both datasets. Comparison with 20-yr averages from the Interim ECMWF Re-Analysis (ERA-Interim) dataset demonstrates that the 2006–07 time period as a whole is reflective of the West Antarctic climate from the last two decades. On the 2006–07 annual means computed from AMPS forecasts, the most salient feature is a tongue-shaped pattern of higher cloudiness, accumulation, and 2-m potential temperature stretching over central WA. This feature is caused by repeated intrusions of marine air inland linked to the sustained cyclonic activity in the Ross and western Amundsen Seas. It is further enhanced by the ice sheet’s topography and by the mid–low-tropospheric wind flow on either side of the central ice divide. Low pressures centered over the Ross Sea (as opposed to the Bellingshausen Sea) are found to be most effective in conveying heat and moisture into WA. This study offers a perspective on how recent and projected changes in cyclonic activity in the South Pacific sector of the Southern Ocean may affect the climate and surface mass balance of WA.
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Pires-Vanin, Ana Maria Setubal. "Identifying the components of ecological variation in a marine benthic megafauna." Revista Brasileira de Oceanografia 49, no. 1-2 (2001): 29–38. http://dx.doi.org/10.1590/s1413-77392001000100003.
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Current work in benthic ecology highlights the importance of the temporal component of ecological variation for distribution and abundance of organisms. However, this approach is limited by the difficulty in separating and measure the constituents of such variation. The present study aims to separate and identify the environmental and temporal components of ecological variation in the abundance of the benthic invertebrate community from the São Sebastião Channel, southeastern Brazil, by canonical correspondence analysis. The area is seasonally submitted to the intrusion of a cold and saline water mass, an important factor influencing benthic communities. The composition and abundance of the megafauna were investigated at five sites from November 1993 to August 1994. A total of 93 species were collected. Average density reached 187 individuals per catch with highest numbers in summer. A striking difference in species composition and abundance was observed in the catches through the year and the results suggested a different structure of the assemblages for each season. Four independent components of the species variation could be separated and identified: pure environmental, pure temporal, environmental with temporal structure and undetermined. The large amount of environmental variation is related to sandy bottoms and depth influence, whereas the time factor can be interpreted as both the seasonal intrusion of the South Atlantic Central Water and the biological cycles of some key-species.
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Urbahs, Aleksandrs, Rima Mickevičienė, Vasilij Djačkov, Kristīne Carjova, Valdas Jankūnas, Mindaugas Zakarauskas, Natalia Panova, and Dita Lasmane. "Analysis of an Unmanned Aerial Vehicle Monitoring System for Resurveying of Shipping Routes." Transport and Aerospace Engineering 3, no. 1 (December 1, 2016): 102–11. http://dx.doi.org/10.1515/tae-2016-0012.
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Abstract The paper gives brief description of the conventional and innovative hydrography survey methods and constraints connected with the realization. Proposed hydrographic survey system based on the use of Unmanned Aerial and Maritime systems provides functionality to conduct hydrographic measurements and environment monitoring. System can be easily adapted to fulfil marine safety and security operations, e.g. intrusion threat monitoring, hazardous pollutions monitoring and prevention operations, icing conditions monitoring.
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Lakhouit, Abderrahim. "Tourism Impact on Marine Ecosystems in the North of Red Sea." Journal of Sustainable Development 13, no. 1 (December 23, 2019): 10. http://dx.doi.org/10.5539/jsd.v13n1p10.
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The unique marine environment of the northern Red Sea region is among the richest and most productive marine ecosystems in the world. The sea is populated with extensive algae blooms and at least five types of coral reefs. However, the region’s tourism sector is largely dependent on the surrounding environment, including the coral reefs, which are highly sensitive to human activities. A large tourist project (Neom) is scheduled to be installed in the northern Red Sea, further increasing tourist activities in the area and leading to human intrusion into crucial but fragile marine habitats such as seagrass beds, coral reefs and mangrove stands. The present study investigates how human activities are currently affecting Red Sea ecosystems. Field visits were done in order to investigate and to study human activities impact on marine ecosystems in the north of Red Sea. To the best of our knowledge, this work is the first of its kind to evaluate the impact of tourism on marine ecosystems in Saudi Arabia’s northern Red Sea coast.
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Pérez-Ceballos, Rosela, Cesar Canul-Macario, Roger Pacheco-Castro, Julia Pacheco-Ávila, Jorge Euán-Ávila, and Martín Merino-Ibarra. "Regional Hydrogeochemical Evolution of Groundwater in the Ring of Cenotes, Yucatán (Mexico): An Inverse Modelling Approach." Water 13, no. 5 (February 26, 2021): 614. http://dx.doi.org/10.3390/w13050614.
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The Ring of Cenotes (RC) extends along the edge of the Chicxulub crater, in the limestone platform of the Yucatan Peninsula (YP), where groundwater shows two preferential flow paths toward the coast near Celestun and Dzilam Bravo towns. The objectives of this study were to describe the regional hydrogeochemical evolution of the groundwater in the RC, and its association with the dissolution/precipitation of the minerals present along its pathway to the ocean. These objectives results were obtained by: (a) characterizing groundwater hydrogeochemistry; (b) calculating calcite, dolomite, and gypsum saturation indexes in the study area; and (c) developing a hydrogeochemical model using PHREEQC (U. S. Geological Survey) inverse modelling approach. The model predictions confirmed that there are two evolution pathways of the groundwater consistent with the preferential flow paths suggested in a previous regionalization of the RC. On the western path, where groundwater flows towards Celestun, marine intrusion influences the hydrogeochemical processes and represents a risk for the freshwater. On the eastern path, where groundwater flows toward Dzilam Bravo, rainfall has an important effect on the hydrogeochemical processes, evidenced by a higher concentration in sulfates during droughts than during rainy periods. Then, monitoring of marine intrusion and phases dissolution in the RC is highly recommended.
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Chen, Yixiang, Shiquan Lin, Chunsheng Wang, Juan Yang, and Dong Sun. "Response of size and trophic structure of zooplankton community to marine environmental conditions in the northern South China Sea in winter." Journal of Plankton Research 42, no. 3 (May 2020): 378–93. http://dx.doi.org/10.1093/plankt/fbaa022.
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Abstract The South China Sea (SCS) is a semi-enclosed marginal sea. And in the northern SCS (NSCS), the Pearl River plume, mesoscale eddies and Kuroshio intrusion may influence the structure of pelagic ecosystems. Here, based on mesozooplankton samples collected in the NSCS from December 2014 to January 2015, spatial variations of mesozooplankton biomass, abundance, normalized biomass size spectra (NBSS), size structure and trophic structure were analyzed to study the response of mesozooplankton community to the influence of highly variable oceanographic environment. High biomass, abundance and intercept of NBSS for the mesozooplankton community were observed in highly productive regions (net primary production > 400 mg C m−2 day−1), such as river plume and cold eddy. No consistent spatial variation was observed for the slope of NBSS, probably because of highly dynamic marine environment in the NSCS. For the trophic structure of mesozooplankton community, the ratio of total chaetognaths biovolume to herbivores/omnivores biovolume (RTCH) was significantly high in river plume and Kuroshio intrusion. The high RTCH indicated unstable trophic structures, which may be due to extreme high proportion of smaller size individuals supported by discharge of river and transport of warm water species from the tropical western Pacific by Kuroshio intrusion, respectively.
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Turek, A., T. M. Carson, Patrick E. Smith, W. R. Van Schmus, and W. Weber. "U–Pb zircon ages for rocks from the Island Lake greenstone belt, Manitoba." Canadian Journal of Earth Sciences 23, no. 1 (January 1, 1986): 92–101. http://dx.doi.org/10.1139/e86-009.
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The Archean Hayes River Group of the Island Lake greenstone belt (Superior Province, Sachigo Subprovince) comprises mafic to felsic metavolcanics, subvolcanics, and associated metasedimentary rocks. The Hayes River Group is intruded by granitoid rocks belonging to the early intrusive complex. One such pluton, the Bella Lake tonalite, is intrusive into the metabasalt of the Hayes River Group and has a U–Pb zircon age of 2886 ± 15 Ma. Similar intrusives of this complex, either internal or marginal to the greenstone belt, yield zircon ages of 2801 ± 8 Ma (Pipe Point tonalit) and 2768 ± 22 Ma (Linklater Island prophyry). This suggests that the early intrusive complex was emplaced over an ~ 120 Ma long interval by at least three separate intrusive episodes.Subsequent to the emplacement of the early intrusive complex, the isoclinally folded Hayes River Group and the early intrusive complex were uplifted, eroded, and followed by the unconformable deposition of the Island Lake Group, comprising fluvial to marine metasedimentary rocks. The stratigraphically lower part of the Island Lake Group is bracketed by the 2768 ± 22 Ma age of the Linklater Island porphyry and the 2729 ± 3 Ma age obtained for the late tectonic suite—the Pipe Point quartz diorite and feldspar porphyry. A feldspar quartz porphyry belonging to the post-tectonic intrusive rocks intrudes higher stratigraphic levels and has been dated at 2699 ± 4 Ma (Horseshoe Island quartz feldspar porphyry).
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Frery, E., M. Ducros, L. Langhi, J. Strand, and A. Ross. "Integrated 3D basin and petroleum systems modelling of the Great Australian Bight." APPEA Journal 57, no. 2 (2017): 733. http://dx.doi.org/10.1071/aj16133.
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3D stratigraphic, structural, thermal and migration modelling has become an essential part of petroleum systems analysis for passive margins, especially if complex 3D facies patterns and extensive volcanic activity are observed. A better understanding of such underexplored offshore areas requires a refined 3D basin modelling approach, with the implementation of realistically sized volcanic intrusions, source rocks and reservoir intervals. In this study, an integrated modelling workflow based on a Great Australian Bight case study has been applied. The 244800-km2 3D model integrates well data, marine surveys, 3D stratigraphic forward modelling and 3D basin modelling to better predict the effects of 3D facies variations and heat flow anomalies on the determination of the source rock-enriched intervals, the source rock maturity history and the hydrocarbon migration pathways. Plausible sedimentary sequences have been estimated using a stratigraphic forward model constrained by the limited available well data, seismic interpretation and published tectonic basin history. We also took into account other datasets to produce a thermal history model, such as the location of known volcanic intrusion, volcanic seamounts, bottom hole temperature and surface heat flow measurements. Such basin modelling integrates multiple datatypes acquired in the same basin and provides an ideal platform for testing hypotheses on source rock richness or kinetics, as well as on hydrocarbon migration timing and pathways evolution. The model is flexible, can be easily refined around specific zones of interest and can be updated as new datasets, such as new seismic interpretations and data from new sampling campaigns and wells, are acquired.
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António, Maria Helena Paulo, Elisa H. Fernandes, and Jose H. Muelbert. "Impact of Jetty Configuration Changes on the Hydrodynamics of the Subtropical Patos Lagoon Estuary, Brazil." Water 12, no. 11 (November 16, 2020): 3197. http://dx.doi.org/10.3390/w12113197.
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Coastal infrastructure alterations, such as jetty expansions, are designed to provide improvements to natural dredging and safety of marine access and to maximize the management and efficiency of ports. Furthermore, these alterations have the potential to cause significant environmental changes to estuaries and adjacent coastal areas. Here, the hydrodynamics of Pathos Lagoon was investigated before and after the jetty alterations, where the jetty was increased by approximately 10–18% and the mouth width was reduced by 15%. The TELEMAC-3D numerical model was calibrated and validated using the field data, and then simulated for characteristic low and high extreme discharge years for the old and new jetty configurations. Results showed a flow reduction of approximately 20% both in the ebb and flood conditions in the new configuration, which was accompanied by a slight change in the propagation angle of the western jetty current. Reduction of the saltwater intrusion was registered during both the high and low discharge conditions with the new jetty configuration. During the high discharge periods with NE winds, saltwater intrusion did not reach the previous estuarine inland boundary. During the period of low discharge with SW wind, salinity did not reach further than 180 km inland. Reduced saltwater intrusion was estimated landwards and in the shallow embayments. The horizontal stratification structure of the salinity changed, with the partial centralization of the flow in the access channel. The observed hydrodynamic changes from the infrastructure modifications could affect the estuarine ecosystem by increasing the sediment retention, reducing the transport of marine organisms and water properties into the estuary. This study contributes not only to the understanding of hydrodynamic changes but also to the potential optimization of estuarine and coastal management strategies.
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Zouhri, Lahcen, El Arbi Toto, Erick Carlier, and Taha-Hocine Debieche. "Salinité des ressources en eau: intrusion marine et interaction eaux–roches (Maroc occidental)." Hydrological Sciences Journal 55, no. 8 (November 29, 2010): 1337–47. http://dx.doi.org/10.1080/02626667.2010.520561.
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Zghibi, Adel, Lahcen Zouhri, and Jamila Tarhouni. "Groundwater modelling and marine intrusion in the semi-arid systems (Cap-Bon, Tunisia)." Hydrological Processes 25, no. 11 (January 24, 2011): 1822–36. http://dx.doi.org/10.1002/hyp.7948.
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Sikkel, Paul C. "Competitor intrusions and mate-search tactics in a territorial marine fish." Behavioral Ecology 9, no. 5 (1998): 439–44. http://dx.doi.org/10.1093/beheco/9.5.439.
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Kvesić, Marija, Marin Vojković, Toni Kekez, Ana Maravić, and Roko Andričević. "Spatial and Temporal Vertical Distribution of Chlorophyll in Relation to Submarine Wastewater Effluent Discharges." Water 13, no. 15 (July 23, 2021): 2016. http://dx.doi.org/10.3390/w13152016.
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The vertical distribution of chlorophyll in coastal waters is influenced by a combination of the hydrodynamic environment and different biotic and abiotic processes. The spatial and temporal occurrences of chlorophyll profiles provide a good representation of the changes in the marine environment. The majority of studies in the Adriatic Sea have so far been conducted in areas unaffected by anthropogenic pressure. Our study site is located near two marine outfalls, which are part of the public sewage system. This study aims to characterize the chlorophyll vertical distribution and describe its variability based on the stratification conditions and the presence of a wastewater effluent plume. Based on these conditions, we identified three characteristic scenarios/types of chlorophyll profiles. The first one occurs when the vertical mixing of the water column creates the upwelling of chlorophyll and nutrients to the upper part of the water column. The second and third scenarios occur during stratified conditions and differ by the extent of the effluent plume intrusion. Using modern fluorescence techniques, we identified and described three different vertical chlorophyll profiles, characterizing them according to their physical and biological parameters and processes. For cases with a visible effluent intrusion, we confirmed the importance of the pycnocline formation in keeping the effluent below and maintaining the higher water quality status at the top of the water column.
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Cooper, A. H., D. Millward, E. W. Johnson, and N. J. Soper. "The early Palaeozoic evolution of northwest England." Geological Magazine 130, no. 5 (September 1993): 711–24. http://dx.doi.org/10.1017/s0016756800021026.
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AbstractThe Lake District and smaller Craven inliers of northwest England contain a Lower Palaeozoic sequence deposited on the Gondwanan side of the Iapetus Ocean, close to the junction with the Tornquist Sea. The Tremadoc to Llanvirn Skiddaw and Ingleton groups are deep water assemblages of turbidite, olistostrome and slump deposits, formed at a continental margin. They experienced uplift and erosion as a precursor to the eruption of two largely subaerial Llandeilo-Caradoc volcanic sequences: the tholeiitic Eycott Volcanic Group in the north and the calc–alkaline Borrowdale Volcanic Group in the central Lake District. The volcanic episodes are the earliest part of a major episode of magmatism, extending through to the early Devonian and responsible for a major batholith underpinning the Lake District. Subsidence in an intra-arc rift zone preserved the subaerial volcanic sequences. A marine transgression marks the base of the Windermere Group, which comprises a mixed carbonate–clastic shelf sequence of Ashgill age, passing upwards through the Silurian into a thick, prograding foreland basin sequence of Ludlow turbidites. Deformation of the Lower Palaeozoic sequences was possibly diachronous from north to south. It is attributed to the late Caledonian (Acadian) Orogeny and resulted in folding, cleavage and thrust development. Granitic intrusions, including those at Shap, Skiddaw and beneath the hydrothermal Crummock Water Aureole, are partly syntectonic and were therefore penecontemporaneous with this deformation event. Some thrust faulting post-dates the intrusive phase. Post-deformation Devonian conglomerates are also present locally.
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Grundmann, Jens, Ayisha Al-Khatri, and Niels Schütze. "Managing saltwater intrusion in coastal arid regions and its societal implications for agriculture." Proceedings of the International Association of Hydrological Sciences 373 (May 12, 2016): 31–35. http://dx.doi.org/10.5194/piahs-373-31-2016.
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Abstract. Coastal aquifers in arid and semiarid regions are particularly at risk due to intrusion of salty marine water. Since groundwater is predominantly used in irrigated agriculture, its excessive pumping – above the natural rate of replenishment – strengthen the intrusion process. Using this increasingly saline water for irrigation, leads to a destruction of valuable agricultural resources and the economic basis of farmers and their communities. The limitation of resources (water and soil) in these regions requires a societal adaptation and change in behaviour as well as the development of appropriate management strategies for a transition towards stable and sustainable future hydrosystem states. Besides a description of the system dynamics and the spatial consequences of adaptation on the resources availability, the contribution combines results of an empirical survey with stakeholders and physically based modelling of the groundwater-agriculture hydrosystem interactions. This includes an analysis of stakeholders' (farmers and decision makers) behaviour and opinions regarding several management interventions aiming on water demand and water resources management as well as the thinking of decision makers how farmers will behave. In this context, the technical counter measures to manage the saltwater intrusion by simulating different groundwater pumping strategies and scenarios are evaluated from the economic and social point of view and if the spatial variability of the aquifer's hydrogeology is taken into consideration. The study is exemplarily investigated for the south Batinah region in the Sultanate of Oman, which is affected by saltwater intrusion into a coastal aquifer system due to excessive groundwater withdrawal for irrigated agriculture.
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Guo, Bao Lin, Xiang Ming Kong, and Yu Han. "A New Moisture Keeping Method for Marine Concrete Curing." Applied Mechanics and Materials 90-93 (September 2011): 1195–99. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1195.
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Cover concrete quality is very important for marine structures, which determines the beginning time of reinforcement corrosion and the life of the structure. The very early age continuous moisture keeping is essential for cover concrete properties develop; otherwise the long-term performance will be reduced heavily. There are many moisture keeping curing methods, but the drawbacks of traditional curing methods make them confined to use in marine environment concrete structures. A kind of moisture keeping membrane which can absorb and hold 100～5000 times of dead-weight water, and impede water evaporating outside with polyethylene film. The results of mercury intrusion porosimetry test and scanning electron microscope show that the new curing product can improve the concrete density decrease the connection degree of pores and the quantity of harmful pores content. Compared with other product on sales, the wet-keeping time can be adjusted and can be used repeatedly and continuously are the distinguishing features, which make it popular in some marine projects.