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1
Ramsell, Joanne. "The influence of plant quality on invertebrate herbivory." Thesis, Lancaster University, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279586.
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Harris, Jean Mary. "Relationships between invertebrate detritivores and gut bacteria in marine systems." Doctoral thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/18326.
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Aspects of the feeding strategies and digestive invertebrate-microbial interactions of two saltmarsh thalassinid detritivores, the mudprawn Upogebia africana (Ortmann) and the sandprawn Callianassa kraussi Stebbing were examined. Resources available in their respective habitats were investigated together with the feeding apparatus, diet and digestive enzymes necessary for hydrolysis of refractory compounds of detritus. U. africana inhabits the upper reaches of Langebaan lagoon (Geelbek),. while C. kraussi was sampled near the mouth (Oesterwal). Both species occur intertidally. Physical characteristics of sediment and water fluctuate more widely at Geelbek than at Oesterwal. Geelbek also has higher mud and clay content in the sediment, and greater particulate load in the water. The resources available in both sediment and water from Geelbek were of greater quality (assessed by proportion of living component, C:N ratio) and quantity. In terms of distribution ofthe resource, quality was highest in surface sediments, while quality was greatest at burrow linings. The mode of feeding, gut structure and diet of the two prawn species differ, although gut throughput rates are similar (ca. 6h). U. africana is a filter feeder which non-selectively ingests small particles which are further sorted in the modified filtertype gastric mill into larger particles which enter the midgut, and smaller particles which are channeled into the hepatopancreas. U. africana has a relatively large throughput gut (fore, mid, hind) allowing large meals to be taken. This may be related to its reliance on vascular plant detritus for both carbon and nitrogen requirements, as shown by stable isotope analyses. By contrast, C. kraussi feeds by a combination of deposit feeding and filter feeding.
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Branch, Margo L. "The benthic invertebrate fauna of subantarctic Marion and Prince Edward Islands." Master's thesis, University of Cape Town, 1994. http://hdl.handle.net/11427/9675.
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Includes bibliographical references.<br>There have been several expeditions to Marion and Prince Edward Islands (MPE) which have sampled the marine fauna and flora, including those of the British ships Challenger (1873-1876) and Discovery (1935), and subsequent surveys by the French ship Marion-Dufresne (Arnaud and Hureae, 1979). South African research began with land-based surveys that concentrated on the intertidal and shallow-water benthos and included work by Fuller (1967), Van Zinderen Bakker et al 1971 ), De Villiers (1976) and Blankley & Grindley (1985). More recently this research was extended offshore by the University of Cape Town, with dredging being undertaken from the SA Agulhas over the period 1984-1989 (GM Branch, Attwood, Gianakouras and ML Branch, 1993) and a quantitative SCUBA survey at depths of 5, 10 and 15m at Bullards Bay, Transvaal Cove and Trypot Point (Beckley and Branch, 1992). The identification of benthic species posed a major problem during each of the recent surveys, despite the fact that the material from earlier expeditions has been referred to international taxonomic authorities. Reference specimens are not available or are housed in European collections. The number of species from the area has also increased considerably. Previous work in the subantarctic has been undertaken by scientists from a large number of countries and over a protracted period of time. Isolated detailed monographs reviewing particular groups have appeared, but these remain largely inaccessible to the more generalist worker. Furthermore many are now out-of-date in terms of the nomenclature employed. This situation prompted the compilation of the present series of identification guides, which are intended to synthesise information on the benthic invertebrate fauna of Marion and Prince Edward Islands and to present it in a manner that will allow relatively easy identification by the non-specialist.
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Dodd, Jennifer Ann. "Long-term change in river invertebrate communities." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2959/.
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Finding rules that govern species distribution and coexistence is a fundamental aim of ecological research. The rapidly expanding and increasingly mobile human race is challenging our understanding of some these rules. Using long-term macroinvertebrate data collected from two river systems with contrasting legacies from human activity, this thesis investigates drivers of change in community structure and function, mechanisms underpinning these changes and how these changes affect the accurate assessment of the ecological condition of river systems. The reformation of the river invertebrate communities within the River Clyde system was not predicted by the simple improving measures of water physico-chemistry or life history characteristics of the re-colonising community. This has serious implications for the accurate assessment of river health which is at present largely reliant on the physio-chemical tolerance of macroinvertebrates to indicate prevailing environmental conditions. It is argued that reference condition predictions, like those obtained from the RIVPACS programme, may not be suitable when assessing the ecological health of a river subjected to long-term modification from human activity, like the River Clyde. Significant differences in the stable isotope signatures of resident and colonising populations of Rhyacophila dorsalis (a predatory Trichopteran) provided insight into some mechanisms underlying differences between reforming communities. Trophic position estimates for some colonising populations of R. dorsalis were shown to be lower than expected considering their predatory status and, colonisation patterns were significant in predicting changes in occupied trophic position. The River Endrick is recognised internationally in terms of biodiversity. Over the last 50 years, the diversity of macroinvertebrate fauna of the river has significantly reduced, five species have become locally extinct and there has been a significant change in the distribution of 29 other species. The macroinvertebrate community in the headwater of the river has undergone a dramatic change in structure and function. The contrasting changes to the headwater community and changes in the structure and function of the macroinvertebrate community in the river system require further investigation. This thesis demonstrates the importance of investigating long-term change.
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Ractliffe, Sylvia Georgiana. "Disturbance and temporal variability in invertebrate assemblages in two South African rivers." Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/12522.
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Includes abstract.<br>This thesis presents an examination of the relationship between floods as disturbances, the disturbance regime and the temporal dynamics of invertebrate assemblages, over the short term and at intra- and inter-annual time scales in the Molenaars and Berg Rivers in the Western Cape of South Africa. Invertebrate responses to individual floods were investigated by a field study that links the displacement of river-bed stones by a flood to change in invertebrate densities and community and population structure from before to after flood events. The magnitude of the hydraulic force acting on each marked stone during the peak of each flood was also calculated, providing a second measure of physical disturbance. Multivariate analyses of similarity, hierarchical clustering and multidimensional scaling were used for analysis of invertebrate patterns before and after floods. Size frequency data for 28 species or genera were analysed to explore changes in population structure over the flood season. Flood records were developed from the daily discharge hydrological record of both study rivers collected by the South African Department of Water Affairs and Forestry. Flood frequency analysis and descriptive statistics were combined with graphical methods to describe the flood regime and to test flood predictability in these rivers. Quantitative monthly samples of invertebrates from the Molenaars River collected over 17 months were used together with a further 2 ½ years of semi-quantitative monthly data, to identify intra- and inter-annual patterns in communities. Multivariate analysis of community patterns was combined with a range of indices that reflect community persistence and stability over periods longer than one generation. Population dynamics of the common species were also studied. Life history attributes, specifically seasonality of life cycle stages and generation time, were explored using size frequency data from the samples.
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Madrigal, J. L. "Models for the study of horizontal movement of nematodes." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354844.
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Halsall, Nigel B. "Time-lapse video studies of invertebrate foraging behaviour, with special reference to Carabidae." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280428.
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Lyons, Candice-Lee. "Evaluating restoration success of alluvial diamond-mined sites in South Africa using invertebrate community indicators." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/8974.
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Gumede, Sabelo Victor. "A study of benthic invertebrate community structure in selected areas on the continental shelf off KwaZulu-Natal, South Africa." Master's thesis, University of Cape Town, 2001. http://hdl.handle.net/11427/6261.
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Wells, Jay. "A pre-impoundment study of the biological diversity of the benthic macro-invertebrate fauna of the Sabie-Sand River system." Master's thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/8401.
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Bibliography: p. 177-205.<br>The Kruger National Park (KNP) in the Eastern Transvaal provides a classic example of the potential conflict of interests between the industrial, agricultural and domestic sectors and conservation. The KNP is situated on the north-eastern border of South Africa and receives the flow of six rivers (Figure 0.1), all •of which originate outside the jurisdiction of the Park authorities. Thus, there are demands for water outside the boundaries of the KNP from other sectors of South Africa, as well as several self-governing states that have been set up as political entities within South Africa (see Chunnett, Fourie & Partners 1987, 1990). Due to human development •of catchments there has been regulation of these rivers, which are rapidly changing in terms of their flow regimes. (O'Keeffe. & Davies 1991). For example, the Letaba and the Luvhuvhu rivers have both changed from perennial to annual flow regimes (O'Keeffe & Davies 1991), a condition which is detrimental to the maintenance of river ecosystem functioning, while the Crocodile River has been regulated to an almost unvarying flow of ca 5m3 s•1 (O'Keeffe & Davies 1991). Recognising the need to address the problem of water allocation to the KNP, the Department of Water Affairs (DW A) convened a workshop on minimum flow needs for the environment in 1987 (Bruwer in press). Although tentative values were suggested for minimum flows, the value of the workshop was its recognition of the need for more research into the problem. Such research is currently being undertaken under the auspices of the multi-disciplinary KNP Rivers Research Programme. The goal of the programme is to " ... develop the means to predict the impact on the KNP river systems of changing flow regimes and water quality as the basis of a protocol for managing the• allocation of water for ecological purposes" (Kruger National Park Rivers Research Programme 1990). One of the studies initiated within this programme was a pre-impoundment study of the Sabie River, including its main tributary, the Sand River, which together are referred to as the Sabie-Sand River system.
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McCracken, David Ian. "Factors affecting the availability of invertebrate food for the chough, Pyrrhocorax pyrrhocorax L." Thesis, University of Glasgow, 1990. http://theses.gla.ac.uk/2911/.
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Most of the fieldwork for this study was conducted on the island of Islay, in the Inner Hebrides, the stronghold of the chough, Pyrrhocorax pyrrhocorax L., in Scotland. The aims of this study were to provide baseline data on the phenology of potential invertebrate foods of the chough, and to provide a greater understanding of the factors affecting these invertebrate populations. The literature concerning (a) the chough in Britain and its feeding ecology, (b) the invertebrate fauna of pasture, (c) the invertebrates associated with cow dung, (d) ivermectin and its effect on the invertebrate fauna associated with cattle dung, and (e) the multivariate analysis methods used in this study, is reviewed. An area of heather moorland and four pastures were selected on Islay. Invertebrates were collected from these sites between January 1988 and November 1989 using pitfall traps, and by sampling soil and cow pats. The data obtained was analysed using two multivariate analysis methods -Two-Way-Indicator-Species- Analysis (TWINSPAN) and Detrended Correspondence Analysis (DECORANA). Information on 62 surface-active taxa was obtained from pitfall trapping. Although seasonal taxa assemblages were recognized, the distribution of the invertebrate communities was primarily related to soil moisture content. Grazing intensity and seasonality were also important factors determining the composition of the invertebrate fauna at each site. The taxa active during the summer and winter at the two sand grassland sites, did not appear to differ as markedly as at the other sites sampled. Figures showing the seasonal activity of some of the frequently occurring taxa at each site considered potential chough prey items are provided. Surface-active potential chough food items were present, at all the sites investigated, throughout the year. Soil-sampling provided information on 34 taxa. As with the surface-active fauna, the primary factor influencing the soil fauna was soil moisture content. The time of year was also an important factor governing the soil fauna composition, with the majority of taxa occurring in low numbers during the summer months at all the sites sampled. Figures indicating the seasonal occurrences of some of the taxa considered potential chough prey items at each site are provided. Soil did not appear to be a good source of potential prey items for the chough during the summer months, although, as a result of seasonal increases in size, certain taxa, e.g. Tipulidae larvae, may have been more 'worthwhile' prey items at this time of year than at any other. Information on 54 taxa was obtained from sampling cow dung. Seasonality and age of the dung were very important in determining the composition of the dung fauna. The seasonal variations in the fauna associated with the cow pats are described. Potential chough prey items were associated with cow dung, in any stage of decay, throughout most of the year. Only during the period from October/November to January did there appear to be a lack of suitably sized potential prey items in the dung. The 'summer' months, when fresh dung contained large numbers of beetle adults and developing fly larvae, and late autumn, when pats deposited during the summer months are old enough for the large numbers of Aphodius spp. larvae present to have attained a reasonable size, were considered to be the times at which cow dung presented the best feeding opportunities for the chough. Fifty taxa were identified in samples of chough faeces. Multivariate analysis of these data indicated that the seasonal availability of prey items was the most important factor influencing chough diet throughout the year. Soil-dwelling Tipulidae (January to July) and Bibionidae (January to April) larvae, dung-associated insects (during the spring, and late summer and autumn), and surface-active insects (during the summer) were important invertebrate components of the diet. Cereal grains were extremely important supplementary food items during the early winter months, when invertebrate availability was low. An experiment was conducted at the College to investigate the effects on the dung fauna of spiking cow dung with 2.0, 1.0, or 0.5 mg/kg dung of ivermectin. Pats were placed on pasture between May and September 1988. The pats were lifted, and the soil beneath sampled, after 15 to 90 days exposure. A total of 65 taxa were identified. These data were analysed using TWINSPAN, DECORANA and Canonical Correspondence Analysis (CANOCO). The major factors determining the invertebrate fauna of the pats were length of exposure, exposure date, and ivermectin presence/absence. Ivermectin markedly affected the fauna associated with the pats. Pats exposed in June and August degraded faster than those exposed in May or September. In June, the ivermectin-treated pats degraded significantly slower than the control pats. An attempt to extract ivermectin from cow dung for analysis by high-performance liquid chromatography is described. This proved unsuccessful and the reasons for this failure, and possible improvements, are discussed. The main conclusions of this study are: (1) that Tipulidae larvae are extremely important components of the chough's diet on Islay, and that the climatic conditions of the island favour these insects; (2) livestock farming on Islay, especially the out-wintering of cattle, provides essential feeding opportunities for the chough, as, (a) gazing animals produce the short sward preferred by the chough as a feeding habitat, (b) large numbers of insects are associated with the dung of these animals, and (c) supplementary feed provided for the cattle in winter also provides an essential alternative food source for the chough at a critical time; (3) the chough's preference on Islay for feeding in sandy, coastal pasture is due to the fact that these sites, (a) contain a variety of suitable invertebrate prey items throughout most of the year, (b) are normally intensively grazed and so contain large amounts of dung with its associated fauna, and (c) are used for out-wintering cattle and therefore cereal grains can be found there; (4) treating cattle with ivermectin could have an adverse effect on the chough as it reduces the number and variety of invertebrates associated with the dung, an important food source for the birds, especially in spring and autumn.
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Cosgrove, Colleen. "COMPARING AQUATIC INVERTEBRATE COMMUNITIES ON PIN OAK, COTTONWOOD, AND RED MAPLE LEAF LITTER IN VERNAL POOLS IN NORTHEASTERN OHIO." Kent State University Honors College / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ksuhonors1430765021.
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Tween, Trevor Charles. "On the occurrence, ecology and behaviour of Onchidella celtica (Gastropoda, Onchidiacea) in the littoral of Cornwall." Thesis, University of Bedfordshire, 1987. http://hdl.handle.net/10547/233628.
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Onchidella celtica is the only onchidiacean to occur in Britain; it is a littoral pulmonate gastropod of controversial taxonomic placement and an historica1 review of the group is therefore presented. The habitat, spatial dispersion, local distribution and geographical range of O.celtica are each described, with particular reference to Cornish shores. The nature of the substratum, exposure and the adverse affects of low temperatures are suggested as the principal parameters controlling the observed distributions, which are considered in detail. O.celtica lays capsular spawn and examination of these has enabled development times and hatching rates to be assessed. Juvenile growth rates have also been investigated to aid the interpretation of population age-structure in shore-line samples, and the dynamics and longevity of the population are discussed. Reproduction is shown to be inhibited by low temperatures. The various reproductive strategies of the onchidiaceans are discussed. Likely causes of mortality are considered, the likelihood of predation by intertidal carnivores is assessed and defensive strategies, including glandular secretions, rhythms of activity and cryptic habits, are shown to be important in evading predation. Various aspects of the behaviour of O.celtica are investigated quantitatively, including aggregation, crevice selection and foraging, and their importance as strategies in successfully exploiting the exposed littoral environment is discussed. A detailed investigation of homing behaviour shows this to be accomplished without obvious trail-following. and remote olfaction is suggested as the principal mechanism of homing. Ambient temperature has a marked effect on the frequency of individuals foraging, and the role of other environmental variables is considered. The feeding behaviour and diet of O.celtica are described, and the possibility of food selection is considered. A preliminary histochemical examination has elucidated the distribution of certain classes of enzymes in the gut of O.celtica.
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Chandler, Margaret Ann. "Population changes in a northern Gulf of California rocky intertidal invertebrate community before and after the 1997--1998 ENSO event." Thesis, The University of Arizona, 1999. http://hdl.handle.net/10150/278712.
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A study was done on a rocky intertidal community in Puerto Penasco, Sonora, Mexico in the summers of 1997--1999 in order to determine if the ENSO of 1997--1998 had an effect on population densities of selected macroinvertebrates. Two replicate transects were laid perpendicular to the sea edge and a census of 21 macroinvertebrate species was taken in the summers of 1997, 1998 and 1999. A significant decrease of species densities occurred in 1998 when the mean sea surface temperature (SST) was more than 2°C warmer than in 1997 due to the 1997--1998 ENSO event. A phenomenon was also observed in 1998 where some species changed, compared to 1997, their vertical distribution in the intertidal from shallow to deeper waters, with a subsequent return to a more expected distribution in 1999. Also a comparison of 1997 and 1976 densities showed an increase in 1997 in abundances of those species with southern geographic ranges and a decrease of those with northern geographic ranges. This was correlated with an increase of mean SST of 1.9°C between the 1970's and the 1990's.
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Bowman, Sarah R. "Utilizing soil characteristics, tissue residues, invertebrate exposures and invertebrate community analyses to evaluate a lead-contaminated site: A shooting range case study." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1437585549.
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Kapusinski, Douglas John. "Factors Affecting Invertebrate and Fish Communities in Coastal Wetlands of the Great Lakes." Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1353202400.
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Ritzenthaler, Cari. "The Effect of Soil Micronutrient Variation Along an Elevational Gradient in a Wet Montane Forest." Bowling Green State University / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1499101412028953.
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Scott, Robyn. "Biogeographical patterns of southern African marine invertebrates." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/6187.
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Includes abstract.<br>Includes bibliographical references (p. 156-171).<br>Biogeography is defined as the study of life, in a spatial and temporal context, with respect to the analysis and explanation of patterns for a given area. The tendency for species richness and diversity to increases towards the equator, where both peak, is a much debated and tested pattern. Underlying mechanisms thought to cause this pattern are: gradients in temperature, stress, productivity, competition, predation, stability, effective evolutionary time, niche breadth, range size and area of occupancy. Evidence exists that both supports and negates most of these mechanisms. In addition to the richness gradient, a latitudinal gradient in geographical range size exists, whereby species range sizes decrease with latitude, referred to as Rapoport's Rule. This has been linked to species ability to tolerate changes in climate. The latitudinal gradient in species richness is thought to be a by-product of Rapoport's Rule and the "Rescue Effect".
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Seidel, Richard Alan. "Conservation Biology of the Gammarus pecos Species Complex: Ecological Patterns across Aquatic Habitats in an Arid Ecosystem." Miami University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=miami1251472290.
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Knight, Gilliam Elizabeth. "A comparative study of purinoceptors in some invertebrates and vertebrates." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.363433.
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Wasson-Hetherington, Lesley H. "Metabolism and molecular mechanisms of toxicity of nitroaromatics in marine invertebrates." Thesis, University of Reading, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309556.
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Koen, Julius Heinrich. "Animal-habitat relationships in the Knysna forest : discrimination between forest types by birds and invertebrates." Master's thesis, University of Cape Town, 1985. http://hdl.handle.net/11427/19521.
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Some silvicultural practices in the Knysna Forest are aimed at the sustained-yield production of valuable timber tree species, albeit on limited areas only. This study investigates effects of forest plant species composition and physiognomy on bird and invertebrate communities in three discrete, relatively undisturbed forest types along a dry-wet soil moisture gradient. Using discriminant functions analysis, a 100% floristic and a 78% vegetation structural discrimination was obtained between the three forest types. However, the bird communities of these floristically and structurally different forest types were very similar in species composition and had much lower densities than normally encountered in other superficially similar forests. It was only possible to discriminate between the wet and the moist/dry forest types by using the two best bird discriminators. the blackheaded oriole (Oriolus larvatus) and the sombre bulbul (Andropadus importunus). A separation of the moist and dry forest types was not possible. Although an 81% discrimination between forest types was attained through analysis of ground surface invertebrates. measures of litter and aerial invertebrate abundance were of limited use as discriminators. Historical and biogeographic factors and the low nutritional levels in the soil and vegetation may be the cause of low bird and invertebrate density and diversity. It is concluded therefore, that floristics and vegetation structure have, at best, a minor influence on bird community structure, and possibly also on the invertebrate community in the Knysna Forest and that management practices need not cater for variation in forest vegetation composition and physiognomy. Bibliography: pages 49-59.
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Ketley, Zoma Anne. "Stream invertebrates and water temperature : evaluating thermal tolerances in the Cape floristic region (South Africa) - implications of climate change." Master's thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/8973.
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Includes bibliographical references.<br>Temperature is an important environmental variable for aquatic invertebrates as it affects their development, reproduction and survival. Temperature also affects the abundance and distribution of individuals in a stream or river. Stream temperatures are affected by human impacts which include not only impacts such as pollution, abstraction of water and the removal of riparian vegetation, but also the affects of climate change. In the Western Cape Province, South Africa, it is predicted that air temperatures will increase and winter rainfall will decrease. This in turn will affect water availability and water temperatures in streams and rivers. Thermally sensitive species are threatened by increases in water temperature, but currently very little information exists on the thermal tolerances of aquatic invertebrates in South Africa. In order to rectify this problem baseline data on thermal tolerances of aquatic species needs to be collected, together with stream temperature and associated invertebrate community data. An attempt was made to collect some of these much needed data in the Western Cape Province. Two methods, namely Critical Thermal Maxima (CTM) and LT₅₀ experiments, were used to determine the thermal tolerances for a range of aquatic insect nymph species from the southwest fynbos bioregion and the south coast fynbos bioregion. The results from the experiments provided information on the relative thermal sensitivities of the species. Overall Aphanicerca capensis (form C and undescribed form), Notonemouridae ranked as the most thermally sensitive for both experiments. The A. capensis species complex (and possible other notonemourid stoneflies) may potentially be used as an indicator of changing stream temperatures in the Western Cape Province. To rapidly determine thermal sensitivities the CTM experiments are recommended rather than the more time consuming LT₅₀ experiments as the relative thermal tolerance for the species tested ranked the same for both experiments. It is suggested that LT₅₀ experiments of longer duration be investigated in order to compare the experiments to naturally-occurring thermal stress. Stream temperature and community composition data were collected from Window Gorge Stream, on Table Mountain, to provide baseline data for future monitoring and understanding of potential changes in thermal profiles. Temperature loggers were placed at six sites along the stream. Stream temperatures were fairly low but the stream ran dry during the late summer months (February through to April/May). From the community composition data collected the highest diversity was found during the winter months, as expected. The community composition did change down the length of the stream, with the species composition found near the source being quite different to that of the species composition found lower down the mountain. Temperature and associated oxygen saturation were two important variables related to the community composition down the length of the stream. It is important that experimental data be combined with field data, enabling field sampling to focus on the collection of information on the abundance of the thermally sensitive species (e.g. A. capensis species complex). Recorded stream temperatures also provide reference conditions for the species tested in the laboratory. Climate change is likely to have an affect not only on stream temperatures but also on water availability, which will both influence stream communities and ecosystems and it is important to understand what these potential effects might be.
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Faulkner, Katelyn Terri. "Phenotypic plasticity of upper thermal tolerance in marine invertebrates at several hierarchical and geographical scales." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/20402.
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Thesis (MSc)--Stellenbosch University, 2012.<br>ENGLISH ABSTRACT: To predict the influence of temperature increases on organisms, and their capacity to respond to climate change, information on the upper thermal tolerance of organisms and its plasticity is required. However, various factors, such as rate of temperature change, may influence basal thermal tolerance and plastic responses, and consequently the vulnerability of organisms to temperature change. Although slower rates of temperature change might be more ecologically relevant, the majority of thermal tolerance studies feature rates of temperature change that are faster than those experienced by organisms in nature. Additionally, studies using slower rates of temperature change have been criticized as factors such as changes in body condition and accumulation of stress over time may confound results. This study determined the influence of fast and slow rates of temperature change and plasticity, induced by acclimation to different temperature conditions for 5 – 15 days, on the upper thermal tolerance of marine amphipod and isopod species from sub-Antarctic Marion Island and South Africa. Using congeners, intra- and inter-specific comparisons of the upper thermal tolerance and plasticity of these organisms were made across geographical regions (South Africa vs. Marion Island), across sites within regions (West coast vs. South coast of South Africa) and between tidal zones. Overall, lower rates of temperature change were found to be associated with lower values of upper thermal tolerance. At fast rates of temperature change, acclimation at high temperatures was associated with an increase in thermal tolerance, whereas at slow rates, acclimation to higher temperatures either had no effect or caused a decrease in thermal tolerance. Furthermore, microclimate recordings suggest that these organisms likely experience rates of temperature increase that are intermediate between the fast and slow rates employed in this study. Thus, in nature these marine invertebrates have upper thermal tolerances that are higher than mean environmental temperature and can likely mount plastic responses during short-term temperature variation. At slow rates of temperature change, however, the upper thermal tolerance of these organisms approximates environmental temperature and plasticity is reduced, likely increasing vulnerability to high temperatures. At the intra-specific level, upper thermal tolerance and plasticity response varied based on mass and sex, however, these effects were species-specific. Isopods inhabiting cooler but more variable microsites on the West coast of South Africa had a higher upper thermal tolerance, but similar magnitude of plasticity, than a population of the same species from the warmer, less variable South coast. Generally, Marion Island species had a lower upper thermal tolerance but higher magnitude of plasticity than South African species. The variability reported here at different hierarchical and geographical scales could be linked to the distinct thermal environments experienced, and the differing physiological and behavioural responses of populations and species to their thermal environments. This variation in thermal tolerance might be critical during environmental change and suggests that species composition may be altered in the future.<br>AFRIKAANSE OPSOMMING: Om die invloed van temperatuur verhogings op organismes, en hul vermoë om te reageer op hierdie verandering, te voorspel, word inligting oor hoë temperatuur verdraagsaamheid van organismes en die plastisiteit hiervan, benodig. Verskeie faktore, soos die tempo van verandering, kan egter basale termiese verdraagsaamheid en plastiese reaksies beïnvloed. Dus, mag dit die tasbaarheid vir temperatuur verandering beïnvloed. Alhoewel stadiger tempo van verandering meer ekologies relevant kan wees, fokus die meerderheid van warm verdraagsaamheid studies op temperatuur veranderinge wat vinniger gebeur as wat ervaar word deur organismes in die natuur. Boonop word studies wat fokus op stadige veranderinge in temperatuur, gekritiseer omdat faktore soos ‘n verandering in liggaamstoestand en die opeenhoping van stres, potentieël die resultate kan belemmer. Hierdie studie ondersoek die invloed van vinnige en stadige temperatuur veranderinge en die plastisiteit, geïnduseer deur akklimasie, met betrekking tot verskeie temperature vir 5-15 dae. Ons fokus spesifiek op die hoë temperatuur verdraagsaamheid van mariene amphipod- en isopod spesies van sub-Antarktiese Marion Island en Suid Afrika. Deur gebruik te maak van spesies wat aan dieselfde genus behoort, is vergelykings getrek tussen intra- en inter-spesies verbande met betrekking tot hul termiese verdraagsaamheid en plastisiteit. Die studie is oor geografiese streke (Suid Afrika vs. Marion Island), tussen areas binne ‘n geografiese streek (Weskus vs. Suidkus van Suid Afrika) en tussen gety sones voltooi. Oor die algemeen was stadige temperatuur veranderinge geassosieër met ‘n laer termiese verdraagsaamheid vir hoë temperature. Met vinnige veranderinge in klimaat, was akklimasie by hoë temperature geassosieër met ‘n hoër temperatuur limiet, maar by stadige temperatuur veranderinge het akklimasie by hoë temperature geen effek gehad nie, of het ‘n afname in termiese verdraagsaamheid veroorsaak. Verder het mikroklimaat opnames aangedui dat hierdie organismes waarskynlik temperatuur verhogings ondervind in hul natuurlike habitat, wat intermediêre is van die vinnige en stadige veranderinge wat in hierdie studie gebruik is. Dus, in die natuur, het hierdie mariene invertebrate `n boonste termiese toleransies wat hoër is as die gemiddelde omgewingstemperatuur en kan hulle waarskynlik van platiese reaksies gebruik maak tydens kort-termyn temperatuur variasie. Gedurende stadige temperatuur veranderinge toon hulle alhoewel hoë termiese verdraagsaamheid teenoor die omgewingstemperature en plastisiteit is verminder, wat heel waarskynlik toenemende kwesbaarheid vir hoë temperature tot gevolg het. Op die intra-spesifieke vlak was wisseling in hoë termiese verdraagsaamheid gebaseer op liggaams massa en geslag, maar hierdie veskille was spesie-spesifiek. Isopoda wat koeler areas bewoon, met meer variasie in hul mikroklimaat, soos ondervind in die Weskus van Suid Afrika, het `n hoër termiese verdraagsaamheid. Maar, soortgelyke mate van plastisiteit, as 'n populasie van dieselfde spesie van die warmer, minder veranderlike Suidkus. Oor die algemeen het Marion-eiland spesies 'n laer termiese verdraagsaamheid, maar hoër grootte van plastisiteit as Suid-Afrikaanse spesies. Die veranderlikheid wat hier geraporteer is, kan op verskeie hiërargiese en geografiese vlakke gekoppel wees aan die unieke termiese omgewings wat hierdie organismes ervaar en aan die verskillende fisiologiese- en gedrags reaksies van populasies en spesies tot hulle termiese omgewings. Die variasie in termiese verdraagsaamheid kan krities wees tydens omgewingsverandering en dui daarop dat spesie-samestelling kan verander in die toekoms.<br>The British Antarctic Survey for funding
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Wale, Matthew A. "The effects of anthropogenic noise playbacks on marine invertebrates." Thesis, Edinburgh Napier University, 2018. http://researchrepository.napier.ac.uk/Output/1255476.
Full textAbstract:
Anthropogenic sound has profoundly changed the acoustic environment of aquatic habitats, with growing evidence that even a short exposure to man-made sound sources can negatively affect marine organisms. Marine invertebrates have received little attention regarding their responses to anthropogenic sound, despite their pivotal role in marine ecosystems, and preliminary evidence of their sensitivity. In this thesis, I critically review the methods used in studies investigating the effects of anthropogenic noise on marine invertebrates. I identify methodological trends that have developed along the timeline of this topic, and use this information to suggest three research strategies to further the development of research in this field. From this review, current knowledge gaps are identified, and two main routes to address them are taken in this thesis. Firstly, to address the shortage of particle motion data in anthropogenic sound literature, two new low-cost and easily accessible particle motion sensors were developed and tested, one of them at 0.1% of the cost of currently commercially available models. These sensors will allow the measurement and reproduction of the sound fields experienced by marine invertebrates in bioacoustic research, even when research budgets are tight. Particle motion is the main sound component detected by invertebrates, yet neglected in many aquatic bioacoustical studies. Secondly, to expand on the comparably small quantity of research investigating the effects of anthropogenic sound on marine invertebrates, a series of controlled laboratory experiments were conducted. Two commercially and ecologically important model species were chosen, the blue mussel Mytilus edulis, representing sessile benthic invertebrates, and the European lobster Homarus gammarus, representing mobile benthic invertebrates. Experiments on M. edulis were conducted taking a mechanistic, integrative approach to investigate the effects of sound on multiple levels of biological organisation, including biochemistry, physiology, and behaviour. The ultimate aim was to understand the underlying drivers behind, and interactions between, responses. Comet assay analysis of haemocytes and gill cells demonstrated a significant six-fold higher single strand breakage in the DNA of cells of mussels exposed to ship-noise playback, compared to those kept under ambient conditions. Superoxide dismutase analysis did not identify an excess of superoxide ions, and glutathione, and glutathione peroxidase assays showed no increase in either glutathione or glutathione peroxidase. TBAR assays however revealed 68% more thiobarbituric acid reactive substances, indicating lipid peroxidation in the gill epithelia of noise exposed specimens. Algal clearance rates and oxygen-consumption rates of noise-exposed mussels were significantly lower (84% reduction and 12% reduction respectively), than those of control animals, while valve gape was significantly (60%) wider. This seemingly converse reaction indicates a shock response in mussels with the onset of noise exposure. Finally, at the genetic level, heat shock protein 70 expression was investigated, but no change was identified during noise exposure. Investigation into the noise induced behavioural responses of H. gammarus suggests seasonal differences in behaviour, using movement as a metric, in response to anthropogenic noise playbacks. During both summer and winter exposures, lobsters spent most time away from the highest noise area (98% of the observed time in summer and 78% in winter). The observed seasonal differences in the time spent in the highest noise area (2% in summer and 22% in winter) could be linked to the lobsters' requirement for shelter during winter. This requirement seems to have had a stronger influence over the animals' behaviour than any desire to avoid high noise levels. The information generated in this thesis can be used by researchers working in the field of marine sound to develop well rounded studies exploring the effects of sound on not only marine invertebrates but other faunal groups as well. The construction details provided to produce low cost particle motion sensors, will allow bioacoustic researchers to easily include particle motion measurements in all future studies investigating the effects of sound on fish and invertebrates. The results of the conducted mussel and lobster experiments evidence how multiple aspects of invertebrate biology can be affected by noise. The observed impacts on both sessile and mobile life forms highlight that the effects of noise cannot be fully understood before a wide range of species with different biological and ecological traits have been studied. The integrative approach to noise research used here can serve as a model for other species, and the results pooled to inform governments and industry of the effects of anthropogenic noise in the marine environment.
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Tigar, Barbara Jane. "The abundance and diversity of desert invertebrates in Abu Dhabi and their role in the diet of the houbara bustard Chlamydotis undulata macqueeni." Thesis, University College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300856.
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Clarke, Jo. "The role of spatial measures in the management and conservation of marine fish and invertebrates." Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8009/.
Full textAbstract:
Historically sea fish were thought to be an inexhaustible resource, in 1882 Thomas Huxley recognised that it was possible to extirpate some fisheries such as the UK oyster and salmon fishery, but he thought "in relation to our present modes of fishing" sea fish were so abundant that they were inexhaustible. Fishing causes impacts other than overfishing, such as bycatch of non-target and vulnerable species discarding and damage to habitats and ecological communities. Fishing intensity has been increasing since the industrial revolution through which technological advances have given fishing vessels the ability to go further and for longer. This has resulted in the need for an ecosystem focused method of management for fisheries, known as ecosystem based fisheries management (EBFM). EBFM requires the development of indicators which represent the ecosystem with which thresholds can be set against fishing pressure. This was investigated for "Sea-pen and burrowing mud megafaunal communities", which have been identified by OSPAR as a threatened or declining habitat in the North Sea and Celtic Seas. Baited cameras were used to monitor mobile megafauna communities across a gradient of fishing intensity to determine which species are sensitive to fishing pressure and could be used in metrics to monitor recovery in areas proposed for protection. Trawling had a negative effect on species richness of mobile megafauna, Munida rugosa, Cancer pagurus and Liocarcinus depurator, but no effect was found on deep burrowing species (Nephrops norvegicus and Goneplax rhomboides). This study identified species that demonstrated different trends with trawl intensity, the trends are related to the ability to burrow and the species mobility. This gives support to the use of biological traits as indicators to detect changes of communities to fishing pressure. In addition to the development of indicators EBFM supports the use of spatial closures as a tool for fisheries management. This method of management is widely used yet remains controversial, often due to the lack of clear objectives and monitoring. Evidence is growing in support of their use but results are often seen after an extended period of long-term monitoring. Clear objectives for each spatial area closure are essential to be able to set relevant targets and reference points, this allows for robust monitoring and improves the ability to effectively manage the area. Although the use of experimental design and statistical analysis to monitor the effects of area closures throughout the world is increasing, there is still a lack of standardisation and the use of theoretically robust survey designs The use of the Before-After, Control-Impact (BACI) design has been identified as the most robust method to monitor areas closed to fishing Few studies have been conducted using this method due to the difficulty in obtaining sufficient temporal and spatial data prior to the implementation of the area closure. There can also be difficulty in identifying suitable reference sites; monitoring begins after closures have already been established or there are limited funds to allow intense temporal and spatial replication. Area closures are particularly beneficial for species which have key life history stages that congregate, such as for spawning. Although the use of area closures are now common place in the UK, this management approach remains controversial due to the frequent lack of clear objectives, monitoring and impact studies. Providing evidence is therefore vitally important to support decision-making for future area closures and to evaluate whether existing closures are achieving their objectives. This was addressed by evaluating an existing seasonal area closure for Atlantic cod (Gadus morhua) in the Firth of Clyde off the Scottish West Coast. The study uses standardised scientific trawl data and a beyond-BACI approach to compare population trends of the Clyde spawning aggregations with two other sub-populations of the same stock. There was no evidence of local recovery in terms of abundance, biomass or reduced mortality in the Clyde more than a decade after the closure was established. Considering the severely depleted state the Clyde sub-population was in when the closure was implemented it appears that the measure was too little and too late. The advantage of EBFM and using an area closure is when there is uncertainty with regard to the effects of fishing on environment and fish stocks, for example if the sensitivity of a habitat to fishing disturbance is unknown or there is not enough data to accurately assess a stocks biomass. This is applicable for deep-sea in the north east Atlantic where since the onset of deep-sea fishing in the 1970s there has been a decline in the abundance of commercial fish species. Management measures were introduced in 2003 which set Total Allowable Catch (TAC) and restricted days at sea, but this still did not allow for the recovery in biomass of commercial species. Also the fishery has high levels of bycatch, including vulnerable deep-sea sharks, which are estimated to have declined by up to 90%. There has been a recent global debate as to whether there is a depth beyond which fisheries cannot be expected to operate in an economically and ecologically sustainable way. The European Union is currently considering new legislation to manage deep-sea fisheries, including the introduction of a depth limit to bottom trawling. However, there is little evidence to suggest an appropriate depth limit. This was addressed using long-term scientific deep-sea trawl data and calculating important ecological and economical indices. The non-linear trend and first derivatives of these indices were calculated with depth. The results suggest that between 600 and 800 m the commercial benefits derived from fishing start to be outweighed by potentially negative ecological consequences. In the marine environment uncertainty is a great impediment for the sustainable management of resources, this thesis demonstrates that with long-term commitments to monitoring, clear objectives and the development of novel techniques to interrogate data, strong evidence can be established to support policy and decision-making.
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Nagahama, Roberto Hiroaki. "Revisão e análise cladística do gênero Plesiopelma Pocock, 1901 (Araneae, Theraphosidae)." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/87/87131/tde-30082010-120834/.
Full textAbstract:
O gênero Plesiopelma Pocock, 1901 é revisado taxonomicamente e realizada análise cladística de suas espécies. A matriz com 30 táxons terminais e 49 caracteres foi analisada com dois programas para reconstrução filogenética, considerando tanto caracteres aditivos como não-aditivos. As quatro análises apresentaram diferenças na topologia, porém três delas demonstram que Plesiopelma é um gênero monofilético. A diagnose e a distribuição geográfica das espécies são apresentadas. São consideradas válidas as espécies P. flavohirtum (Simon, 1889), P. semiaurantiacum (Simon, 1897),P. myodes Pocock, 1901, P. insulare (Mello-Leitão, 1923), P. physopus (Mello-Leitão, 1926), P. minense (Mello-Leitão, 1943) e P. simoni (Soares e Camargo, 1948). É proposta a sinonímia de P. rectimanum (Mello-Leitão, 1923) e P. longisternale (Schiapelli e Gerschman, 1942) com P. myodes. São reconhecidas seis espécies novas para o Brasil. É proposta a transferência de P. imperatrix Piza, 1976 para o gênero Megaphobema Pocock, 1901 e P. gertschi (Caporiacco, 1955) é considerada Incertae sedis.<br>The genus Plesiopelma Pocock, 1901 is taxonomically revised and a cladistic analysis of its species is done. The matrix with 30 terminal taxa and 49 characters was analysed with two programs for phylogenetic reconstruction. The four analyses showed different topologies on the internal group, however, three of them show Plesiopelma being a monophyletic genus. The diagnoses and geographic distribution of all species are presented. It is herein considered valid the species P. flavohirtum (Simon, 1889), P. semiaurantiacum (Simon, 1897), P. myodes Pocock, 1901, P. insulare (Mello-Leitão, 1923), P. physopus (Mello-Leitão, 1926), P. minense (Mello-Leitão, 1943) and P. simoni (Soares e Camargo, 1948). The species P. rectimanum (Mello-Leitão, 1923) and P. longisternale (Schiapelli & Gerschman, 1942) are considered junior-synonyms of P. myodes. It is recognized six new species from Brazil. It is proposed the transfer of P. imperatrix Piza, 1976 to Megaphobema Pocock, 1901 and P. gertschi (Caporiacco, 1955) is considered Incertae sedis.
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Muller, Cornelius Marthinus. "The phylogeographic population structure of the Cape sea urchin, Parechinus angulosus." Thesis, Stellenbosch : Stellenbosch University, 2011. http://hdl.handle.net/10019.1/6899.
Full textAbstract:
Thesis (MSc)--Stellenbosch University, 2011.<br>ENGLISH ABSTRACT: South Africa's coastline is in the region of 3650kms and encompasses many different and dynamic marine environments. To enhance our current understanding of the population structure and gene flow patterns of intertidal zone marine species in this region, this study sets out to investigate the phylogeographic population structure of the Cape sea urchin, Parechinus angulosus, using mitochondrial and nuclear DNA sequence data collected in 2007 and 2008. Individuals were sampled from 18 geographic locations between southern Namibia and Durban, covering nearly the full extent of the species range. Sequence data were obtained from a 790bp region of the COI mtDNA gene (n=510) and a 182bp region of the nDNA SpREJ9 gene (n=145), respectively. The mtDNA data revealed 283 polymorphic sites (36%) defining 195 haplotypes, of which 160 were unique and 35 shared among individuals. Haplotype diversity (h) was found to be high both overall (h=0.95) and for individual localities (h=0.75-0.98), with nucleotide diversity (π) being low overall (π=0.013) as well as for individual localities (π=0.0033-0.0254). AMOVA revealed significant population structure among sampling sites in the Namaqua Province biogeographical region, as well as between three of the four respective coastal biogeographic provinces/regions. Gene flow was bi-directional among sampling sites in the south coast Agulhas and East Coast Province biogeographical regions, while gene flow in the Namaqua Province appears to be dominated by northwards movement. BAPS identified a significant break in the Cape Point region, which was also reflected in the gene flow patterns and parsimony networks. This broadly corresponds to previously identified biogeographic regions as well as genetic breaks for other marine species found along this coast. Fu's Fs statistics showed strong signal(s) of population expansion for individual sampling localities as well as for the data set as a whole, while MDIV estimated a time since expansion ranging from 7733-4759 years ago. The nDNA data revealed 54 variable sites (29.7%), defining 72 alleles of which 50 were unique and 22 shared among individuals. Many of the alleles (69.4%) were restricted to single sampling sites, with Betty's Bay on the south coast being the most diverse from a genetic viewpoint. Allelic diversity was high overall (h=0.86) while nucleotide diversity was low (π=0.025). No nuclear sub-group structure was identified by BAPS, although the parsimony network revealed shallow genetic structure between the Namaqua and Agulhas Provinces, with significant pairwise ФST values also recovered between their individual coastal localities. This points to at least one major barrier to gene flow for Parechinus angulosus along the South African coast, namely Cape Point. Several additional, smaller hindrances to gene flow along the coast were also identified, most of which are congruent with findings from studies on both other and sea urchin species. As a standalone study this research elucidated many aspects regarding the phylogeography of the Cape sea urchin, P. angulosus. However, it is when viewed in the broader context of invertebrate phylogeography along the southern African coastline that this research will provide its most critical insight.<br>AFRIKAANSE OPSOMMING: Geen opsomming
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Schuldt, Andreas [Verfasser], and Thorsten [Akademischer Betreuer] Aßmann. "Patterns and drivers of biodiversity: insights from a hyperdiverse invertebrate taxon (Coleoptera: Carabidae) / Andreas Schuldt. Betreuer: Thorsten Aßmann." Lüneburg : Universitätsbibliothek der Leuphana Universität Lüneburg, 2010. http://d-nb.info/1034194682/34.
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Gohse-Reimann, Sandra Sabine [Verfasser]. "Untersuchungen zur Ernährungsökologie benthischer Invertebraten im Makrophytensystem : ein marin-limnischer Ansatz / Sandra Sabine Gohse-Reimann." Kiel : Universitätsbibliothek Kiel, 2008. http://d-nb.info/1019621338/34.
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Gola, Nontuthuzelo Pearl. "A comparison of biomarkers in assessing the combined effects of pesticide mixtures on non-target soil invertebrates." Thesis, Stellenbosch : University of Stellenbosch, 2004. http://hdl.handle.net/10019.1/16327.
Full textAbstract:
Thesis (MSc)--University of Stellenbosch, 2004.<br>ENGLISH ABSTRACT: Agricultural environments are usually contaminated with mixtures of antropogenically
introduced chemicals as a result of pesticide spraying, which can affect beneficial, nontarget
soil invertebrates, such as earthworms negatively. Most studies on mixture toxicity
have focused on interactions of chemicals with similar structures and mechanisms.
However, chemical mixtures may occur as conglomerates of diverse structures and
toxicological mechanisms in the environment.
This study was aimed at assessing the effects of pesticides singly, and in a mixture, on
earthworms, using lifecycle parameters (growth and reproduction) and biomarkers
(neutral red retention (NRR) assay and acetylcholinesterase (AChE) inhibition) as
endpoints. Thus, to determine whether any interactions occurred between the pesticides
as shown by the measured endpoints. Another aim was to validate the use of the chosen
biomarkers for assessing mixture toxicity.
The pesticides used were from three groups: organophosphates, heavy metal-containing
pesticides and pyrethroids. From these three groups, four of the most commonly used
pesticides in the orchards and vineyards of the Western Cape, South Africa, were chosen,
namely chlorpyrifos (organophosphate), azinphos-methyl (organophosphate), copper
oxychloride (heavy metal-containing fungicide) and cypermethrin (pyrethroid).
Earthworms were exposed in the laboratory to a range of concentrations of chlorpyrifos
and copper oxychloride singly, and in 1:1 mixtures of these pesticides in artificial soil, for
four weeks. After the exposure period, the biomass change was determined as measure
of growth, and cocoon production, hatching success and number of hatchlings per cocoon
were determined as measures of reproduction.
Growth (biomass change) and reproduction (cocoon production) were affected by the
highest concentration treatment (20mg/kg) of chlorpyrifos, but copper oxychloride and
the mixture of the two pesticides showed no observable effects on lifecycle parameters.
Dose related effects on NRR times were however determined for both pesticides and the
mixture. Dose related effects on AChE activity were found for chlopyrifos and the
mixture of the two pesticides, but not for copper oxychloride. Short-term exposures (48
hours) of earthworms to the following pesticides in artificial groundwater: chlorpyrifos, copper oxychloride, azinphos-methyl, cypermethrin, chlorpyrifos-copper oxychloride,
chlorpyrifos -azinphos-methyl and chlorpyrifos-cypermethrin, were done followed by the
determination of AChE inhibition. Dose related effects were exhibited on the AChE
activity of earthworms exposed to chlorpyrifos, a mixture of chlorpyrifos and copper
oxychloride, azinphos-methyl, and a mixture of azinphos-methyl and chlorpyrifos.
Copper oxychloride, cypermethrin and the mixture of chlorpyrifos and cypermethrin had
no effect on AChE activity. Earthworms died at the highest exposure concentration of
the mixture of chlopyrifos and cypermethrin.
Results have shown that although the pesticides did not cause observable effects on
lifecycle parameters, there were effects at subcellular and biochemical level, as shown by
the biomarkers. Mixtures of pesticides, in some instances, affected earthworms
differently from their single components, indicating interactions between the pesticides in
mixtures, as shown by the measured endpoints. The NRR assay proved to be a good
general biomarker of soil contamination, and the AChE activity could also be a valuable
tool in assessing the effects of organophosphate mixtures and mixtures of
organophosphates and pesticides from other groups.<br>AFRIKAANSE OPSOMMING: Nie-teiken organismes, soos erdwurms, word negatief beïnvloed deur mengsels van
antropogeniese chemikalieë in landbou-omgewings. Die meeste studies wat handel oor
die toksisiteit van chemiese mengsels het tot dusver gefokus op chemikalieë van dieselfde
aard en met dieselfde meganismes van werking. Mengsels van chemiese stowwe kan
egter as konglomerate van 'n verskeidenheid strukturele eienskappe en met verskillende
toksiese meganismes in die omgewing aangetref word.
Tydens die studie is gepoog om die effekte van enkel pestisiede sowel as mengsels
daarvan op erdwurms te bestudeer, deur van lewensloop kenmerke (groei en
voortplanting) en biomerkers (neutraalrooi retensietyd - NNR en inhibisie van
asetielcholienesterase -AChE) as eindpunte gebruik te maak. 'n Verdere doel van die
studie was om vas te stel of daar enige wisselwerkings tussen die verskillende pestisiede
plaasvind, soos aangetoon deur die gemete eindpunte, en verder ook om die gebruik van
die gekose biomerkers as maatstawwe van mengseltoksisiteit te evalueer.
Die pestisiede wat gebruik is, is van drie verskillende groepe afkomstig: organofosfate,
swaarmetale en piretroiede. Van hierdie drie groepe is vier van die pestisiede wat vry
algemeen in boorde en wingerde in die Weskaap, Suid-Afrika, gebruik word,
geïdentifiseer. Hierdie stowwe is chlorpyrifos (organofosfaat), azinphos-metiel
(organofosfaat), koperoksichloried (swaarmetaalbevattende fungisied) en sipermetrien
(piretroied).
Erdwurms is in die laboratorium aan 'n reeks konsentrasies van chlorpyrifos en
koperoksichloried as enkel toksikante en as 1:1 mengsels in kunsmatige grond, vir vier
weke blootgestel. Voor en na die blootstellingsperiode is die biomassa van die wurms, as
maatstaf van groei, bepaal en kokonproduksie, uitbroeisukses en getal nakomelinge per
kokon bepaal as maatstawwe van voortplantingsvaardigheid. Groei
(biomassaverandering) en voortplanting (kokonproduksie) is beinvloed deur behandeling
met die hoogste konsentrasie (20 mg/kg) chlorpyrifos, terwyl geen effek van
koperoksichloried of die mengsel van hierdie twee pestisiede gevind is nie. Daar is gevind dat beide die pestisiede, enkel en in die mengsel, die NRR tye beinvloed het. Die
AChE aktiwiteit is beinvloed deur chlorpyrifos en die mengsel, maar nie deur die
koperoksichloried nie.
Korttermyn blootstellings van erdwurms (48 uur), in kunsmatige grondwater, van
erdwurms aan chlorpyrifos, koperoksichloried, azinphos-metiel en sipermetrien as enkel
toksikante en mengsels van chlorpyrifos-koperoksichloried, chlorpyrifos-azinphos-metiel
en chlorpyrifos-sipermetrien, is gedoen en gevolg deur die bepaling van AChE inhibisie.
Koperoksichloried, cypermetrien en die chlorpyrifos-sipermetrien mengsel het geen
waarneembare effek op die AChE aktiwiteit gehad nie ?????. Die erdwurms wat
blootgestel is aan die hoogste konsentrasie in die mengsel van chlorpyrifos-sipermetrien
het doodgegaan.
Die resultate het getoon dat die pestisiede nie in die korttermyn die lewensloopkenmerke
in enige waarneembare mate geaffekteer het nie maar daar was effekte op sellulêre en
biochemiese vlakke soos aangetoon deur die biomerkers. Sommige mengsels van die
pestisiede het die erdwurms verskillend van die enkelstowwe geaffekteer. Daar het dus
wisselwerking tussen sommige van die pestisiede wat in mengsels aangewend is,
plaasgevind, soos aangetoon deur die gemete eindpunte. Die NRR toets, as breë-spektrum
biomerker was 'n goeie maatstaf van kontaminasie in grond en daar is aanduidings dat
die AChE aktiwiteit, as 'n spesifieke biomerker, 'n nuttige maatstaf kan wees om die
effekte van organofosfaatmengsels en mengsels van hierdie chemiese groep en die van
ander chemikalieë aan te toon.
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Neves, Isabela Monteiro. "Ascídias didemnidae (Tunicata, Ascidiacea) da Região de Bocas Del Toro - Panamá = Didemnidae ascidians (Tunicat, Ascidiacea) from Bocas del Toro - Panamá." reponame:Repositório Institucional da UFPR, 2015. http://hdl.handle.net/1884/37618.
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Orientadora : Profª. Drª. Rosana Moreira da Rocha<br>Dissertação (mestrado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Zoologia. Defesa: Curitiba, 06/02/2015<br>Inclui referências<br>Area de concentração: Zoologia<br>Resumo: Didemnidae é a família mais diversa e mais derivada da ordem Aplousobranchia (classe Ascidiacea). Compreende cerca de 600 espécies, representando 20% de todas as ascídias conhecidas até o momento. As águas tropicais do Caribe são conhecidas pela riqueza e abundância de invertebrados marinhos e a costa atlântica do Panamá é caracterizada pela
presença de um mosaico de hábitats variados que proporcionam importantes substratos naturais para a comunidade incrustante. O presente trabalho apresenta descrições detalhadas de didemnídeos coletados entre os anos de 2003 e 2014 em 12 pontos do arquipélago de Bocas del Toro – Panamá. Foram identificadas 19 espécies, das quais cinco haviam sido registradas na região (Diplosoma listerianum, Lissoclinum verrilli, Didemnum granulatum, D. psammatodes e Trididemnum orbiculatum), sete são novos registros (Lissoclinum abdominale, Didemnum calliginosum, D. cineraceum, D. perlucidum, D. vanderhorsti, Trididemnum palmae e T. thetidis) e sete são espécies novas (Diplosoma sp. nov. 1, Diplosoma sp. nov. 2, Lissoclinum sp. nov. 1, Lissoclinum sp. nov. 2, Didemnum sp. nov., Trididemnum sp. nov. 1 e Trididemnum sp. nov. 2). Com estes resultados, o Panamá está entre as regiões do Caribe com maior número de didemnídeos registrados, mostrando a importância de se considerar a região objeto de esforço no monitoramento e na conservação dos diferentes hábitats e dos invertebrados marinhos que ali habitam.
Palavras-chave: Aplousobranchia, ascídias coloniais, características morfológicas, Caribe,
Diplosoma, Didemnum, Lissoclinum, taxonomia, Trididemnum, Tunicata.<br>Abstract: Didemnidae is the most diverse and the more derived family from Aplousobranchia order (Ascidiacea class). Comprising ca. 600 species, that represents 20% of all known ascidians. The Caribbean tropical waters are known for the richness and abundance of marine invertebrates and the Panama Atlantic coast is characterized by the presence of different habitats that provide important natural substrates for sessile communities. This paper reports detailed descriptions of didemnids collected between 2003 and 2014 in 12 points in the archipelago of Bocas del Toro - Panama. Nineteen species were identified, of which five have been previously registered in the region (Diplosoma listerianum, Lissoclinum verrilli, Didemnum granulatum, D. psammatodes and Trididemnum orbiculatum), seven are new records (Lissoclinum abdominale, Didemnum calliginosum, D. cineraceum, D. perlucidum, D. vanderhorsti, Trididemnum palmae and T. thetidis) and seven are new species (Diplosoma sp. nov. 1, Diplosoma sp. nov. 2, Lissoclinum sp. nov. 1, Lissoclinum sp. nov. 2, Didemnum sp. nov., Trididemnum sp. nov. 1 and Trididemnum sp nov. 2). With these results, Panama is among the regions of the Caribbean Sea with the highest number of didemnids, showing the importance of considering the monitoring effort and conservation of different habitats and marine invertebrates that live in this region.
Keywords: Aplousobranchia, colonial ascidians, Caribbean Sea, Diplosoma, Didemnum,
Lissoclinum, morphology, taxonomy, Trididemnum, Tunicata.
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Castellano, Giovanna Carstens. "A atividade da anidrase carbônica em invertebrados de diferentes ambientes." reponame:Repositório Institucional da UFPR, 2017. http://hdl.handle.net/1884/46302.
Full textAbstract:
Orientador : Profª. Drª. Carolina Arruda de Oliveira Freire<br>Tese (doutorado) - Universidade Federal do Paraná, Setor de Ciências Biológicas, Programa de Pós-Graduação em Zoologia. Defesa: Curitiba, 21/02/2017<br>Inclui referências : f. 110-117<br>Area de concentração<br>Resumo: Todos os invertebrados evoluíram no ambiente marinho e, posteriormente, alguns conquistaram os ambientes dulcícola e terrestre. Cada ambiente apresenta diferentes características de fatores abióticos, como salinidade e/ou disponibilidade de água. Neste contexto, o objetivo deste trabalho foi o de relacionar respostas fisiológicas de invertebrados à ocupação de novos ambientes (dulcícola e terrestre). No capítulo 1, espécies marinhas, estuarinas e dulcícolas de invertebrados foram expostas a estresse salino, sendo, equinodermos (apenas marinhas), moluscos, e crustáceos. Posteriormente foram realizadas análises de concentrações osmótica e iônicas de seus fluidos corporais, e de teor hídrico e atividade da anidrase carbônica (AAC) de seus tecidos. No capítulo 2, quatro espécies de caranguejos da família Sesarmidae com diferentes graus de terrestrialidade, eurihalinidade e atividade motora foram avaliados quanto à osmolalidade da hemolinfa e à atividade da anidrase carbônica das brânquias anteriores e posteriores. No capítulo 3, três espécies de poliquetas de diferentes ambientes foram estudados. A osmolalidade e a AAC constitutivas foram analisadas, e a capacidade de regulação de volume celular foi testada diante de choques osmóticos de 50% de intensidade com relação ao controle isosmótico. Nestes capítulos, buscou-se relacionar mecanismos fisiológicos (principalmente AAC) à conquista dos ambientes diluídos e terrestre. Resumidamente, os resultados demonstraram que a conquista de novos ambientes (não marinhos) demandam investimento energético em mecanismos fisiológicos que possibilitem a manutenção de gradientes osmóticos e/ou iônicos entre os meios interno (fluido corporal do animal) e externo (ambiente). A amplitude destes gradientes é proporcional ao grau de sucesso do grupo zoológico na conquista de novos ambientes (e.g. crustáceos apresentam maiores gradientes do que equinodermos). A manutenção de hidratação tecidual também é importante na conquista de novos ambientes, principalmente em espécies osmoconformadoras. A AAC tem diferentes magnitudes e funções em diferentes ambientes, sendo elevada nos ambientes marinho, dulcícola e terrestre, e baixa no estuarino. Em todos os ambientes a enzima provavelmente exerce função de equilíbrio ácido-base, mas a função osmorregulatória se restringe às espécies não marinhas. A novidade do trabalho foi a abordagem comparativa, relacionando AAC a diferentes grupos zoológicos de invertebrados, e ao seu grau de conquista de ambientes de água doce e terrestres. Além disso, AAC é muito pouco estudada nos grupos dos equinodermos e dos poliquetas. Então, sob essa visão altamente comparativa, foi possível detector os padrões fisiológicos que seguem: 1) AAC se relaciona ao ambiente, e tende a ser mais alta em habitantes marinhos, dulcícolas e de água muito diluídas do que em espécies estuarinas; 2) AAC e os gradientes osmóticos / iônicos são diretamente proporcionais à eurihalinidade e ao sucesso na conquista de novos ambientes por uma espécie, e por um grupo como um todo; 3) a capacidade de manutenção de volume celular / tecidual contribui para a tolerância à salinidade de osmoconformadores e para o grau de eurihalinidade de osmorreguladores. Palavras-chave: crustáceos, equinodermos, moluscos, poliquetas, transição ambiental.<br>Abstract: All invertebrates evolved in the sea and, later, some conquered freshwater and terrestrial environments. Each environment has different characteristics of abiotic factors such as salinity and/or water availability. In this context, the aim of this study was to relate physiological responses of invertebrates to the occupation of new environments (freshwater and terrestrial). In chapter 1, marine, estuarine and freshwater species of invertebrates were exposed to salt stress, being echinoderms (marine only), molluscs, and crustaceans. Then analyzes were performed on osmotic and ionic concentrations of their body fluids, water content and carbonic anhydrase activity (CAA) of their tissues. In Chapter 2, four species of Sesarmidae crabs with varying degrees of terrestriality, euryhalinity, and motor activity were evaluated for hemolymph osmolality and CAA in anterior and posterior gills. In chapter 3, three species of polychaetes from different environments were studied. The constitutive osmolality and CAA were analyzed, and the cell volume regulation capacity was tested under hypo and hyperosmotic shocks of 50% intensity in relation to the isosmotic control. In these chapters, we sought to relate physiological mechanisms (mainly CAA) to the conquer of freshwater and terrestrial environments, respectively. Briefly, the results have shown that the conquest of new environments (non marine)require energy investment in physiological mechanisms that enable the maintenance of osmotic and / or ionic gradients between the internal (body fluid of the animal) and external media (environment). The magnitude of these gradients is proportional to the degree of success of the zoological group in winning new environments (e.g. crustaceans have higher gradients than echinoderms do). Tissue hydration maintenance is also important in invading new environments, especially in osmoconformer species. CAA has different magnitudes and functions in different environments, being high in marine, freshwater and terrestrial environments, and low in the estuarines. In all environments, the enzyme probably exerts acid-base balancing, but osmoregulatory function is restricted to non-marine species. The novelty here was the comparative approach relating CAA to different zoological groups of invertebrates, and to their degree of conquest of freshwater and terrestrial environments. In addition, CAA is understudied in the groups of echinoderms and polychaetes. Thus, under this highly comparative view we could detect the following physiological patterns: 1) CAA is related to environment, and tend to be higher in dwellers of marine, freshwater, and very diluted waters than in estuarine species; 2) CAA and osmotic / ionic gradients are directly proportional to the euryhalinity and to the success of conquest of new environments of a species, and even of a group as a whole; 3) capacity of maintenance of cell / tissue volume contributes to the salinity tolerance of osmoconformers and to the degree of euryhalinity of osmoregulators. Key-words: crustaceans, echinoderms, environmental transition, molluscs, polychaetes.
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Sondermann, Martin [Verfasser], and Daniel [Akademischer Betreuer] Hering. "Modelling the spatial dispersal of aquatic invertebrates to predict (re-)colonisation processes within river catchments / Martin Sondermann ; Betreuer: Daniel Hering." Duisburg, 2018. http://d-nb.info/1154385876/34.
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Njovu, Henry Kenneth [Verfasser], and Ingolf [Gutachter] Steffan-Dewenter. "Patterns and drivers of herbivore diversity and invertebrate herbivory along elevational and land use gradients at Mt. Kilimanjaro, Tanzania / Henry Kenneth Njovu ; Gutachter: Ingolf Steffan-Dewenter." Würzburg : Universität Würzburg, 2019. http://d-nb.info/1200355326/34.
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Miranda, Mary [Verfasser]. "Impact of Anthropogenic Stressors on Marine Benthos : Anthropogenic Stress on Macrobenthic Invertebrate Assemblages along the Southern Coast of Kerala, India / Mary Miranda." München : GRIN Verlag, 2018. http://d-nb.info/1172292272/34.
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Wentrup, Cécilia [Verfasser], Nicole [Akademischer Betreuer] Dubilier, and Monika [Akademischer Betreuer] Bright. "Acquisition and activity of bacterial symbionts in marine invertebrates / Cécilia Wentrup. Gutachter: Nicole Dubilier ; Monika Bright. Betreuer: Nicole Dubilier." Bremen : Staats- und Universitätsbibliothek Bremen, 2012. http://d-nb.info/1072046628/34.
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Babin, Régis. "Contribution à l'amélioration de la lutte contre le miride du cacaoyer Sahlbergella singularis Hagl. (Hemiptera : Miridae). Influence des facteurs agro-écologiques sur la dynamique des populations du ravageur." Phd thesis, Université Paul Valéry - Montpellier III, 2009. http://tel.archives-ouvertes.fr/tel-00871800.
Full textAbstract:
L'objectif de ce travail est d'améliorer notre compréhension des mécanismes et d'évaluer les facteurs agro-écologiques impliqués dans la dynamique spatio-temporelle des populations naturelles de Sahlbergella singularis. Le calcul des tables de vie sur une population d'élevage a révélé que S. singularis est une espèce à croissance lente. Ceci expliquerait le fait que le ravageur est généralement présent à de faibles densités dans les plantations. L'étude des paramètres démographiques de la population d'élevage a montré que la fécondité est un paramètre-clé des fluctuations saisonnières des populations naturelles. Leur croissance serait liée à la présence de jeunes cabosses sur les cacaoyers fournissant aux femelles une ressource alimentaire favorable à la reproduction. L'étude de l'influence des facteurs agro-écologiques sur les densités de populations de S. singularis en plantation a révélé que les densités dépendent des conditions parcellaires de culture du cacaoyer. Parmi les pratiques culturales, les traitements insecticides, l'ombrage et le recours aux variétés hybrides sont des facteurs déterminants. En outre, les populations du ravageur sont fortement agrégées dans les zones des plantations bénéficiant d'un ensoleillement maximal. Enfin, l'ombrage fourni par les arbres forestiers s'est avéré plus homogène que l'ombrage d'arbres fruitiers et par conséquent moins propice au développement des poches à mirides. Les recommandations de lutte préconisées par la recherche agronomique sont rarement appliquées par les planteurs. Aussi, nos résultats ont-ils été discutés dans l'optique d'adapter ces recommandations au contexte de culture du cacaoyer qui prévaut actuellement au Cameroun
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Witt, Jan [Verfasser], Wolf [Akademischer Betreuer] Arntz, and Karsten [Akademischer Betreuer] Reise. "Analysing brackish benthic communities of the Weser estuary: spatial distribution, variability and sensitivity of estuarine invertebrates / Jan Witt. Gutachter: Wolf Arntz ; Karsten Reise. Betreuer: Wolf Arntz." Bremen : Staats- und Universitätsbibliothek Bremen, 2004. http://d-nb.info/1072301792/34.
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Smith, Megan L. "Investigating drivers of diversification in a co-distributed community of terrestrial gastropods from the Pacific Northwest." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586171520981707.
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Reinhardt, Timm [Verfasser], Markus Akademischer Betreuer] [Gutachter] Weitere, Thomas [Gutachter] Berendonk, and Sebastian [Gutachter] [Steinfartz. "New home, new life: The effect of shifts in the habitat choice of salamander larvae on population performance and their effect on pond invertebrate communities / Timm Reinhardt ; Gutachter: Markus Weitere, Thomas Berendonk, Sebastian Steinfartz ; Betreuer: Markus Weitere." Dresden : Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://d-nb.info/1136567267/34.
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Corti, Roland. "Assèchement des cours d'eau : effets sur les communautés d'invertébrés et la dynamique de la matière organique particulaire." Phd thesis, Université Claude Bernard - Lyon I, 2013. http://tel.archives-ouvertes.fr/tel-00828092.
Full textAbstract:
Les transitions terrestre-aquatique jouent un rôle primordial dans le fonctionnement des écosystèmes. Dans les cours d'eau qui cessent de s'écouler périodiquement, ces transitions se développent latéralement au travers des zones ripariennes mais aussi longitudinalement le long du lit du cours d'eau. L'objectif de ce travail de thèse était de déterminer les effets de ces transitions terrestre-aquatique dans les lits des cours d'eau sur les communautés d'invertébrés terrestres et sur dynamique de la matière organique particulaire, un processus écologique fondamental au fonctionnement des cours d'eau. Les résultats montrent que communautés d'invertébrés ripariens sont peu dépendantes des ressources aquatiques du cours d'eau mais sont essentielles au maintien de la diversité en invertébrés dans les lits asséchés. La matière organique est transportée et se décompose par à coup lors des conditions aquatiques, influençant potentiellement la disponibilité en nutriments dans les réseaux hydrographiques
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Christopher, Cory C. "Effects of invasive Amur honeysuckle (Lonicera maackii) and white-tailed deer (Odocoileus virginianus) on native plants, leaf litter communities, and soil." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1212097775.
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Mdzeke, Naomi Patience. "Contamination levels in and cellular responses of intertidal invertebrates as biomarkers of toxic stress caused by heavy metal contamination in False Bay." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/53733.
Full textAbstract:
Thesis (PhD) -- Stellenbosch University, 2004.<br>ENGLISH ABSTRACT:Heavy metals are persistent environmental contaminants whose sources of inputs into
the environment are both natural and anthropogenic. The levels of heavy metals
(cadmium, copper, nickel, lead and zinc) in the False Bay intertidal zone were
measured in the water, sediments and invertebrate species between August 2000 and
August 2001. The results of the water and sediment analyses revealed that most
pollution was associated with the northern shore of the bay between Strand and
Muizenberg, where the most populated and industrial catchments occur. Significant
spatial variations occurred, indicating the presence of localised contamination, while
seasonal variations may be related to changes in precipitation and runoff at different
times of the year. The concentrations of cadmium, nickel and lead were occasionally
higher than the levels recommended by the South African Water Quality Standards.
The possible sources of pollution at the different sites are also discussed. The
concentrations of the five metals in the different invertebrate species (Oxystele
tigrina, 0. sinensis, Choromytilus meridionalis, Patella oculus, Patiriella exigua and
Tetraclita serrata) also revealed significant seasonal and spatial variations, with both
the soft tissues and shells accumulating heavy metals. The barnacle T serrata from
Rooiels had the highest cadmium concentration (70.67 J.lg/g dry weight), which may
be related to historic pollution inputs from the military activities which took place at a
weapons testing site at this site between 1987 and 1994, although no evidence was
found to confirm this. The periwinkle 0. tigrina from Strand had the highest copper
concentration (70.25 J.lg/g) while the limpet P. oculus from the same site had the
highest nickel concentration (35.75 J.lg/g). The shells of the mussel C. meridionalis
from Muizenberg had the highest concentration of lead (25.75 J.lg/g). Since cadmium
occurs as a constituent of phosphate fertilisers used widely in the False Bay
catchments, the effects of cadmium exposure on the different species were
investigated during 14-day laboratory exposures to 200 and 400 J.lg/LCdCh. The
results revealed a general pattern of tissue metal increase in the exposed organisms,
followed by slight reductions after decontamination in clean seawater. The viscera
and kidneys of C. meridionalis accumulated most of the dissolved cadmium. The
shells of the mussels also accumulated cadmium, indicating the possible use of shells
as a detoxification matrix.<br>AFRIKAANSE OPSOMMING:Swaarmetale is persisterende omgewingskontaminante waarvan die insetbronne beide
natuurlik of van menslike oorsprong kan wees. Die kontaminasievlakke van
swaarmetale (kadmium, koper, nikkel, lood en sink) in die Valsbaai tussengetysone is
in die water, sedimente en invertebraatspesies bepaal vanaf Augustus 2000 tot
Augustus 2001. Voorlopige resultate van die water- en sedimentontledings het getoon
dat die meeste besoedeling by die noordelikke oewer van die baai voorgekom het
tussen Strand and Muizenberg, waar die mees digbewoonde en ge-industrialiseerde
opvangsgebiede is. Betekenisvolle ruimtelike en seisoenale variasie het in die
konsentrasies van swaarmetale voorgekom, met die ruimtelike variasie wat moontlik
gelokaliseerde kontaminasie aandui terwyl die seisoenale variasies weer verband mag
hou met veranderings in die neerslag en afloop gedurende verskillende tye van die
jaar. Die konsentrasie van kadmium, nikkel en lood was somtyds hoer as die vlakke
wat deur die Suid-Afrikaanse Waterkwaliteitsstandaarde voorgestel word. Die
moontlike bronne van besoedeling in die verskillende areas is ook in bespreking
genoem. Die konsentrasies van die vyf swaametale in die verskillende
invertebraatspesies (Oxystele tigrina, 0. sinensis, Choromytilus meridionalis, Patella
oculus, Patiriella exigua and Tetraclita serrata) het ook seisoenale en ruimtelike
variasies vertoon, die swaarmetale het in die sagte weefsel en skulpe van die
invertebrate geakkumuleer. Die hoogste gemiddelde konsentrasie van kadmium
(70.67 ).lg/g droe massa) is in die heel-liggaam monsters van die eendemossel T
serrata gemeet wat by Rooiels versamel is. Die vlakke mag verband hou met die
oprigting en aktiwiteite van die wapentoetsingsaanleg in die opvanggebied van die
Rooiels lokaliteit tussen 1987 en 1994, maar geen bewyse daarvan is gevind nie. Die
tolletjie, 0. tigrina wat in die 10kaliteit by Strand versamel is het die hoogste
gemiddelde konsentrasie koper gehad 70.25 pig droe massa), terwyl die klipmossel
P. oculus by dieselfde versamelpunt die hoogste konsentrasie nikkel (35.75 ).lg/gdroe
massa) gehad het. Eksperimentele studies is ook uitgevoer op vier invertebraat
spesies wat vir 14 dae in akwaria blootgestel is aan see-water met 200 en 400 p,g/L
CdCh, en daama gedekontamineer is in skoon seewater.<br>The NRF and the University of Stellenbosch, for funding this study.
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Baeta, Alacio Marc. "Ecology of some keystone invertebrates inhabiting shallow soft bottom communities of the Maresme coast (NW Mediterranean Sea)." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/295965.
Full textAbstract:
Bivalves living in large aggregations of individuals (reefs or beds), such as mussels, clams, cockles and some high trophic predators such as sea stars, play an essential ecological role in the structure, integrity, stability, and diversity of the biological communities; being usually considered as keystone species. Their disappearance or decline could lead to disproportionate effects in their communities, even affecting the survival of other species. Although keystone species are crucial for maintaining the Earth biodiversity, often their study has not taken enough attention. The main aim of this Doctoral Thesis was to study the ecology of some keystone invertebrates inhabiting shallow soft bottom communities of the Maresme coast (Northwestern Mediterranean Sea). The results enhance the knowledge of the smooth clam (Callista chione) and also of its potential predators, several species of sea stars (Astropecten spp.) co-occurring in the area. But at the same time, our findings help to understand their trophic interactions, the status of their populations and propose guidelines for their conservation. Maresme coast is close to Barcelona and it has concentrated historically a high anthropogenic pressure that has altered and modified its environment. Our results have showed the critical status of the smooth clam bed as a consequence of the combination of different human coastal uses: sand dredging and clam fisheries. These anthropogenic pressures have also led to significant changes in Astropecten populations. A. aranciacus has been shown to be the most vulnerable, and consequently the most affected, to the extent that its population suffers an important and worrying decline. Moreover, A. aranciacus reproductive cycle, growth and depth segregation between size classes along the continental shelf have been described for the first time. Our results have documented Astropecten species niche segregation, which allow them to co-occur within a biological community scale, without compete for the same available recourses. Sea stars showed a partitioning of the prey (species) and microhabitats in the Maresme coast. This Doctoral Thesis aims to provide a valuable background to improve the conservation of these keystone invertebrates, as well as to promote the sustainable exploitation of shellfish.<br>Els bivalves que viuen en grans agregacions d'individus, com ara algunes espècies de musclos, cloïsses i escopinyes; i alguns predadors que ocupen elevats nivells tròfics com ara les estrelles de mar juguen un paper fonamental en l'estructura, integritat, estabilitat i diversitat de les comunitats biològiques, sent habitualment considerats com espècies clau. La seva desaparició o declivi pot conduir a efectes desproporcionats sobre el conjunt de les comunitats on habiten, fins i tot afectant la supervivència d'altres espècies. Tot i que les espècies clau són essencials per mantenir la biodiversitat al planeta Terra, sovint no s'ha prestat prou atenció al seu estudi. El principal objectiu d'aquesta Tesi Doctoral ha estat l'estudi de l'ecologia d’algunes d’aquestes espècies clau que habiten els fons tous poc profunds de la costa del Maresme (nord-oest del Mar Mediterrani). Els resultats obtinguts milloren de manera significativa el coneixement de la població de petxinot de sang (Callista chione) i dels seus potencials depredadors, diferents espècies d'estrelles de mar (Astropecten spp.) que cohabiten a la zona. Al mateix temps ajuden a entendre les seves relacions tròfiques, l'estat de les seves poblacions i es proposen pautes per a la seva conservació. La costa del Maresme és molt propera a la ciutat Barcelona, i per això ha concentrat històricament una elevada pressió antropogènica que ha modificat i alterat el seu medi ambient. Els resultats d'aquesta Tesi Doctoral mostren com l'estat crític de la població de petxinot de sang (C. chione) és conseqüència de la combinació de diferents pressions antropogèniques: dragatges de sorres i la pesca de bivalves amb dragues. També s'ha observat que aquestes mateixes pressions han produït canvis significatius en les poblacions d'estrelles de mar Astropecten. A. aranciacus ha resultat ser l'estrella més vulnerable a aquestes pressions i en conseqüència ha estat la més afectada, veient-se la seva població disminuir a un ritme preocupant. A més, s'ha descrit per primera vegada la reproducció, el creixement i la segregació batimètrica per mida de A aranciacus. Els resultats obtinguts també mostren que les diferents espècies de Astropecten poden cohabitar per la segregació dels seus nínxols ecològics permeten-los no competir pels recursos disponibles (preses i hàbitat). Aquesta Tesi Doctoral pretén proporcionar un rerefons valuós per a millorar la conservació d'aquestes espècies clau, així com promoure l'explotació sostenible dels mol·luscs bivalves.<br>Los bivalvos que viven en grandes agregaciones de individuos, como por ejemplo algunas especies de mejillones, almejas y berberechos; y algunos predadores que ocupan elevados niveles tróficos como por ejemplo las estrellas de mar juegan un papel crucial en la estructura, integridad, estabilidad y diversidad de la comunidades biológicas, siendo habitualmente considerados como especies clave. Su desaparición o declive puede conducir a efectos desproporcionados sobre el conjunto de sus comunidades, incluso afectando la supervivencia de otras especies. Aunque las especies clave son esenciales para mantener la biodiversidad en el planeta Tierra, a menudo no se ha prestado suficiente atención a su estudio. El principal objetivo de esta Tesis Doctoral fue el estudio de la ecología de algunas especies clave que habitan los fondos blandos y someros de la costa del Maresme (noroeste del Mar Mediterráneo). Los resultados obtenidos mejoran de forma significativa el conocimiento sobre la concha fina (Callista chione) y sus depredadores potenciales, distintas species de estrellas de mar del género Astropecten que cohabitan en la zona. Al mismo tiempo ayudan a entender sus relaciones tróficas, el estado de sus poblaciones y se proponen pautas para mejorar su conservación. La costa del Maresme se halla cerca de la ciudad Barcelona, y por ello ha concentrado históricamente una elevada presión antropogénica que ha modificado y alterado su medio ambiente. Los resultados de esta Tesis Doctoral muestran como el estado crítico de la población de concha fina (C. chione) es consecuencia de la combinación de distintas presiones antrópogenicas: dragados de arenas y pesquerías de moluscos bivalvos. También se ha observado que estas mismas presiones han producido cambios significativos en las poblaciones de estrellas de mar Astropecten. A. aranciacus ha resultado ser la estrella más vulnerable a dichas presiones y en consecuencia ha sido la más afectada, viéndose su población disminuir a un rito preocupante. Además, se ha descrito por primera vez la reproducción, el crecimiento y la segregación batimétrica por tallas de A. aranciacus. Los resultados documentados también muestran que las distintas especies de Astropecten pueden cohabitar por la segregación de sus nichos ecológicos permitíendoles no competir por los recursos disponibles (presas y hábitat). Esta Tesis Doctoral pretende proporcionar un trasfondo valioso para mejorar la conservación de estas especies clave, así como promover la explotación sostenible de los moluscos bivalvos.
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Duran, i. Alarcon Sandra. "Phylogeography Gene Flow and Population Structure of "Crambe Crambe" (Porifera: Poecilosclerida)." Doctoral thesis, Universitat de Barcelona, 2003. http://hdl.handle.net/10803/780.
Full textAbstract:
The main goal of this thesis has been to study the population structure of a marine sponge species (<i>Crambe crambe</i>) at different geographic levels using different molecular markers.<br/><br/>In many organisms, particularly terrestrials, molecular markers have been used to answer questions about the structure and connectivity of populations, the potential of dispersal or the history of species, and these data were of crucial help in conservation and management of species. Most of these studies used allozymes and, more recently, mitochondrial or nuclear sequences with success. Also, microsatellite markers are being developed and applied with terrific success in many species. Unfortunately, application of molecular markers in marine environments lags much behind, especially for invertebrate organisms, where population genetic studies are still scarce and most of them involve only allozymes. Thus, this study attempts to be contribute to the development and application of molecular markers for ecologic and population genetic studies in marine invertebrates.<br/> Most marine invertebrate organisms are benthic, and many of them sessile, with larvae as the main form of dispersal. Because of the intrinsic difficulty on following larval movements in natural environments, molecular markers appear as the perfect tool to track and characterize populations, and even individuals. <br/>Hence, in this thesis several molecular markers have been applied in a sponge species, and with the complementary help of previous ecological and biological knowledge of the species, the present-day population structure of this sponge has been studied, trying to uncover which factors are affecting and might have affected in the past the structure found, while comparing the resolution and the "snapshot" information recovered with each of the markers used.
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Solé, Carbonell Marta. "Statocyst sensory epithelia ultrastructural analysis of Cephalopods exposed to noise." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/84184.
Full textAbstract:
Controlled Exposure Experiments revealed lesions in the statocysts of four cephalopod species
of the Mediterranean Sea (Sepia officinalis, Loligo vulgaris, Illex coindetii and Octopus
vulgaris), when exposed to relatively low intensity low frequency sounds. The analysis was
performed through: scanning (SEM) and transmission (TEM) electron microscopy techniques of
the whole inner structure of the cephalopod statocysts, especially on macula and crista; SEM of
the epidermal lines of cephalopod hatchlings; and proteomic studies (2DE/MALDI –MS) of the
statocyst’s endolymph. All exposed adult individuals presented the same lesions and the same
incremental effects over time, consistent with a massive acoustic trauma observed in land
species that were exposed to much higher intensities of sound. Immediately after exposure, the
damage was observed in the macula statica princeps (msp) and in the crista sensory epithelium.
Kinocilia on hair cells were either missing or were bent or flaccid. A number of hair cells
showed protruding apical poles and ruptured lateral plasma membranes, most probably resulting
from the extrusion of cytoplasmic material. Hair cells were also partially ejected from the
sensory epithelium, and spherical holes corresponding to missing hair cells were visible in the
epithelium. The cytoplasmic content of the damaged hair cells showed obvious changes,
including the presence of numerous vacuoles and electron dense inclusions not seen in the
control animals. The appearance of these lesions became gradually more pronounced in
individuals after 12, 24, 48, 72, and 96 hours. Special attention was given to validate these
findings with control animals that were caught, maintained and sequentially sacrificed following
the same protocol as the exposed individuals. The statocyst ultrastructure was therefore revisited
and a comparative analysis was carefully conducted to assess the lesions triggered by the
exposure to noise
This study also presents preliminary results of the sound effects on epidermal lines of
cephalopod hatchlings. The lesions, consistent with an acoustic trauma, were identic in the three
species that were exposed, but their evolution over time, in opposition with what was observed
in the statocysts, were different, suggesting that the animal size and metabolic response might
play a role in a possible recovery process.
The analysis of noise effects in the statocyst endolymph by proteomic techniques was only
conducted on Sepia officinalis. The presence of differential staining of gels from control and
subjected to sound exposure individuals demonstrate that the injuries could be related to a
possible physiological imbalance that would affect the protein levels of the endolymph.
The lesions and findings described here are new to cephalopod pathology. Given that lowfrequency
noise levels in the ocean are increasing (e.g. due to shipping, offshore industry, and
naval maneuvers), that the role of cephalopods in marine ecosystems is only now beginning to
be understood, and that reliable bioacoustic data on invertebrates are scarce, the present study
and future investigations will bring an important contribution to the sustainable use of the
marine environment.<br>Després de sotmetre'ls a experiments d'exposició controlada a sons de baixa intensitat i baixa freqüència es van observar lesions en els estatocists de quatre espècies de cefalòpodes de la mar Mediterrània (Sepia officinalis, Loligo vulgaris, Illex coindetii i Octopus vulgaris). L'anàlisi es va realitzar per mitjà de de microscòpia electronica d'escombratge (SEM) i de transmissió (TEM) de tota l'estructura interna de l'estatocist dels cefalòpodes, especialment en la màcula i en la crista, per SEM de les línees epidèrmiques de les larves dels cefalòpodes i per tècniques de proteòmica (2DE/MALDI-MS), de l'endolimfa de l'estatocist. Tots els estatocists d'individus adults de cefalòpodes exposats presentaven les mateixes lesions i aquests efectes eren més greus a mesura que passava el temps després de l'exposició als sons. Tots els animals exposats al soroll van mostrar lesions consistens amb trauma acústic massiu observat en altres espècies terrestres que havien estat exposades a intensitats molt més altes de so. Immediatament després de l'exposició, es van observar danys a la macula statica princeps (msp) i en l'epiteli sensorial de la crista. Els quinocilis de les cèl·lules ciliades desapareixien o es doblegaven i es tornaven flàccids. Un nombre important de cèl·lules ciliades mostraven els pols apicals sobresortint de l'epiteli sensorial, així com el trencament de les membranes plasmàtiques laterals, molt probablement com a resultat de l'extrusió de material citoplasmàtic. Les cèl·lules ciliades també van ser parcialment expulsades de l'epiteli sensorial deixant visibles forats esfèrics en el mateix. El contingut citoplasmàtic de les cèl·lules ciliades danyades va mostrar canvis obvis, com ara la presència de nombrosos vacúols i inclusions electrodenses que no es veien en els animals control. L'aparició d'aquestes lesions es va tornar gradualment més pronunciada en els individus analitzats després de 12, 24, 48, 72 i 96 hores. Es van validar curosament aquests resultats per mitjà de la comparació amb els animals control que van ser capturats, mantinguts i sacrificats de forma seqüencial seguint el mateix protocol que els individus exposats. La ultraestructura de l'estatocist va ser revisada i es va dur a terme un curós anàlisi comparatiu per tal d'avaluar les lesions provocades per l'exposició al soroll. Aquest estudi també presenta els resultats preliminars dels efectes del so en les línies epidèrmiques de cefalòpodes recent nascuts. Les lesions, consistens amb trauma acústic, eren idèntiques en les tres espècies que van ser exposades, però la seva evolució en el temps, en oposició amb el que es va observar en els estatocists, era diferent, cosa que suggereix que la grandària dels animals i la resposta metabòlica podria tenir influència en un possible procés de recuperació. L'avaluació dels efectes en l'endolimfa de l'estatocist per tècniques de proteòmica es va dur a terme només en Sepia officinalis. La presència de taques diferencials en els gels dels individus control i els sotmesos a exposició a so demostren que les lesions podrien estar relacionades amb un possible desequilibri fisiològic que tindria repercusions en els nivells proteics de l'endolimfa. Les lesions descrites aquí són noves pel que fa a la patologia dels cefalòpodes. Atès que els nivells de soroll de baixa freqüència a l'oceà estan augmentant (per exemple, a causa del transport, la indústria petrolera i les maniobres navals), que el paper dels cefalòpodes en els ecosistemes marins només ha començat a ser entès recentment, i que les dades bioacústiques fiables sobre els invertebrats són escasses, el present estudi i les investigacions futures aportaran una important contribució a l'ús sostenible del medi marí.
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Mecho, Lausac Ariadna. "Taxonomy, distribution and community composition of megabenthic non-crustacean invertebrates in the deep Catalan margin = Taxonomía, distribución y composición de la comunidad de invertebrados no crustáceos del megabentos del Mar Catalán profundo." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/284473.
Full textAbstract:
The study of the non-crustacean invertebrates dwelling on the deep Mediterranean Sea is of interest for different marine science disciplines, being the diversity of species and their distributions largely unexplored. In fact, the present Thesis conducted an effort in order to increase valid scientific information not only at taxonomical level, but also at the level of community composition and distribution. Detailed data on the reproductive biology and ethology was required for some group of ecological relevance in order to solve some relevant gaps of information. Ten multidisciplinary oceanographic cruises were conducted between October 2008 and April 2013 to sample the deep seafloor of the western Mediterranean Sea. The sampling areas included the Blanes Canyon and its adjacent open slope, the Palamós (also named La Fonera) and Cap de Creus Canyons, sea hills in the Gulf of Valencia and Eivissa Channel, and landslides on the Eivissa Channel. A total of 223 benthic trawls were completed resulting in a total swept area of 10.3 km². Samples were also observed by means of two ROV’s. Resulting from these ten cruises, this work evidenced and updated species bathymetrical and geographical distributions ranges of non-crustacean invertebrate species by different methodologies (i.e. traditional and technologically advanced sampling). As a result of that effort, new faunistic reports were described: two first records (i.e. Gracilechinus elegans (Düben & Koren, 1844) Dicopia antirrhinum C. Monniot, 1972), three rare species (i.e. Hedingia mediterranea (Bartolini Baldelli, 1914), Penilpidia ludwigi (von Marenzeller, 1893) and Phascolosoma (Phascolosoma) turnerae (Rice, 1985), and eleven extensions of maximum depth range of distribution. This new record for Dicopia antirrhinum increased the lower depth limit of this genus in the Mediterranean Sea from 500 to 1100m depth. This finding contributes to the knowledge of the poorly investigated Mediterranean deep ascidian fauna, in sharp contrast with the relatively well-known shallow-water Mediterranean ascidians. We also observed that densities and biomass of non-crustacean invertebrates were pointed to be significantly higher in submarine canyons than in surrounding open slopes. These findings suggest submarine canyon habitats of the north-western Mediterranean Sea as hotspots of benthic megafauna communities. The most abundant group in terms of density was the Phylum Echinodermata. A Phylum largely undescribed in deep Mediterranean waters, when compared with the faunistic data already available for the Atlantic. All specimen sampled of this Phylum were classified, described and their bathymetrical ranges re-defined. These results were compared and extended with the previous published literature, checking, validating (or discarding) all available information. The reproductive pattern of the most abundant species of Asteroidea in the present study, Ceramaster grenadensis was studied. The size pattern distribution of show a depth related trend showing smaller sizes at greater depths (dwarfism), as observed in other species of Atlantic Ocean. Additionally, juveniles were sampled at the deepest range of distribution of the species (i.e. 2250 m). Histological analysis of C. grenadensis gonads, revealed a semicontinous reproductive patterns, with a maximum of reproductive activity in autumn (maximum values of Gonadal Index). This finding coincides with some already published study for other deep-sea Mediterranean Echinoderm species such as B. lyrifera. The in situ faunal sampling with video technologies (i.e. Remotely Operated Vehicles; ROVs) showed the occurrence of different species assemblage compositions in different geomorphological habitats such as, submarine canyons, sea hills and landslides. Benthic cnidarian communities were observed in seamount rocky areas while submarine landslides fauna were mainly composed by vagil fauna as fishes and crustaceans. The description of characteristics seascape units might help to estimate taxonomical group in other similar but presently unexplored deep-sea areas. Finally, this study suggests that an increasing effort combining traditional and technologically-new sampling methods is advisable in order to obtain a more complete overview of species inhabiting the different deep-sea continental margins.<br>En el estudio de la presente tesis se pretende realizar una exhaustiva clasificación taxonómica de las especies de invertebrados no-crustáceos muestreados en el margen catalán profundo, así como determinar sus patrones de distribución y su composición faunística. El material utilizado fue recopilado a lo largo de 10 campañas oceanográficas realizadas entre octubre 2008 y abril 2013 en el Mediterráneo occidental en el marco de los Proyecto Nacionales y Europeos PROMETEO, DOSMARES, BIOFUN, PROMARES y EUROLEON. Las áreas de muestreo incluyeron el Cañón de Blanes y su talud adyacente, los cañones de la Fonera y Cap de Creus, dos montañas submarinas ubicadas en el Golfo de Valencia y el Canal de Ibiza, y dos deslizamientos submarinos del Canal de Ibiza. Adicionalmente se realizó una campaña transmediterránea en la cual se muestrearon tres áreas del Mediterráneo, oeste, central y este. Se utilizaron para la recolección de muestras tanto métodos de muestreos tradicionales (artes de arrastre) como nuevas tecnologías de muestreo visual (ROV). Las profundidades muestreadas mediante ROV fueron de entre los 60 m y los 1100 m de profundidad; y entre los 850 m y los 2850 m mediante muestreos tradicionales. Se obtuvieron 5877 individuos distribuidos en 8 Filos, 18 Clases y 69 especies. En la presente Tesis se describe por primera vez en el Mediterráneo la presencia de dos especies: el equinoideo regular Gracilechinus elegans (Düben & Koren, 1844) y la ascidia carnívora Dicopia antirrhinum C. Monniot, 1972. Igualmente se describió la presencia de tres especies consideradas ‘raras’: las holoturias endémicas Hedingia mediterranea (Bartolini Baldelli, 1914) y Penilpidia ludwigi (von Marenzeller, 1893) así como el sipúnculido Phascolosoma (Phascolosoma) turnerae Rice, 1985. Asimismo se amplió el rango de distribución batimétrica de 11 especies. Los datos se analizaron además de a nivel puramente taxonómico, a nivel poblacional, revelando mayores densidades (individuos • km -2) y biomasas (kg • km -2) en zonas de cañones submarinos. También se observó que a nivel faunístico el grupo más abundante fueron los equinodermos, representando el 57% del total de especímenes recolectados. Si pasamos a considerar los datos obtenido mediante imágenes de ROV, se recopilaron un total de 4520 observaciones faunísticas de los tres hábitats geomorfológicos descritos (un cañón, dos montes y dos deslizamientos submarinos) y entre los cuales se describieron similitudes en cuanto a comunidades faunísticas en función de parámetros tales como la profundidad, geomorfología y tipo de substrato.
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Taboada, Moreno Sergio. "Antarctic marine benthic invertebrates: chemical ecology, bioactivity and biodiversity / Invertebrados bentónicos marinos de la Antártida: ecología química, bioactividad y biodiversidad." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/83921.
Full textAbstract:
Esta tesis cubre diferentes aspectos de los invertebrados marinos bentónicos de la Antártida. Se trata de una tesis multidisciplinar presentada en formato artículos en la que se hacen las siguientes aportaciones: (i) por un lado se hace una revisión de los productos naturales de origen animal y vegetal descritos hasta Mayo de 2007 en las aguas de la Antártida. En dicha revisión se hace especial énfasis en el papel que juegan los productos naturales en el contexto de su ecosistema; (ii) se aportan también datos sobre experimentos de repelencia alimentaria en los que se utilizaron extractos lipofílicos de invertebrados bentónicos de 2 zonas muy poco estudiadas (este del Mar de Weddell e Isla de Bouvet). En dichos experimentos, que se llevaron a cabo utilizando depredadores simpátricos, se ha demostrado que algo más de la mitad de los invertebrados testados poseen defensas químicas que los defienden frente a posibles depredadores. En algunos de estos casos las defensas químicas parecen localizarse en las partes más expuestas/vulnerables de los organismos testados; (iii) uno de los artículos de esta tesis confirma el potencial antitumoral que tienen los invertebrados marinos bentónicos antárticos y sub-antárticos. Se trata del estudio antitumoral más grande que jamás se haya hecho en este área con resultados muy prometedores para phyla como Chordata, Porifera y Cnidaria, entre otros; (iv) por último se describen un total de 4 nuevas especies de anélidos poliquetos de las aguas someras de la Antártida. Dichos organismos pertenecientes a las familias Cirratulidae (1 especie del género Cirratulus), Dorvilleidae (2 especies del género Ophryotrocha) y Siboglinidae (1 especie del género Osedax), fueron descritos a partir de huesos de ballena colocados experimentalmente en las aguas de Isla Decepción (Islas Shetland del Sur). Estos hallazgos confirman la importancia que los huesos de ballena pueden tener en el contexto de las aguas de poca profundidad de la Antártida.<br>The Thesis entitled “Antarctic marine benthic invertebrates: chemical ecology, bioactivity and biodiversity" covers different aspects related to Antarctic marine benthic invertebrates. This is a multidisciplinar thesis comprising several scientific papers making the following contributions: (i) on the one hand it revises the described Antarctic marine natural products derived from animals and algae up to May 2007. In this revision, special emphasis is given to the role that these natural products play in their ecosystem; (ii) this thesis also provides data from feeding repellent experiments using lipophilic extracts from benthic invertebrates from two poorly known areas (eastern Weddell Sea and Bouvet Island). These experiments, carried out using sympatric predators, showed that more than half of the invertebrates tested possess chemical defenses against possible predators. In some of the cases, these defenses seem to be located in the most exposed/vulnerable parts of the organisms; (iii) one of the papers included in this thesis confirms that marine benthic invertebrates from Antarctic and sub-Antarctic waters have an interesting antitumoral potential. This work is the largest carried out in the area with very promising results for phyla such as Chordata, Porifera, and Cnidaria, among others; (iv) finally, this thesis comprises the description of 4 new species of annelid polychaetes from the Antarctic waters. These organisms belong to the families Cirratulidae (1 species from the genus Cirratulus), Dorvilleidae (2 species from the genus Ophryotrocha) and Siboglinidae (1 species from the genus Osedax), which were described from whale bones experimentally deployed in Deception Island (South Shetland Islands). These findings confirm the importance that whale bones may have in the Antarctic shallow-waters context.