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Ritter, Mary Christine. "Benthic succession in a Texas estuary : the influence of hypoxia, salinity fluctuations, and disturbance frequency /". Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Leiter, Carola. "Benthos-Foraminiferen in Extremhabitaten". Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-95510.
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Nickel, Jörg. "Bentho-pelagische Kopplungsprozesse im arktischen Mellemfjord (Westgrönland) unter besonderer Berücksichtigung benthischer Peracarida (Malacostraca, Crustacea) = Benthic-pelagic coupling in the Arctic Mellemfjord (West-Greenland) with special focus on benthic Peracarida (Malacostraca, Crustacea) /". Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2004. http://www.gbv.de/dms/bs/toc/470608676.pdf.
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Masikane, Ntuthuko Fortune. "Nearshore subtidal soft-bottom macrozoobenthic community structure in the western sector of Algoa Bay, South Africa". Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1466.
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The objectives of this study were to characterise macrozoobenthic community structure of the western sector of Algoa Bay, to identify the drivers of community structure and to develop a long-term monitoring framework. Data were collected from six study sites stratified along-shore. Each site comprised three stations; most sites were located in areas directly influenced by anthropogenic activities such as inflow from storm water drains and areas where dredged spoil was dumped. Other sites included areas in close proximity to estuary mouths. Physico-chemical parameters of the water column were measured with a YSI instrument, sediment for faunal and physico-chemical analyses was sampled with a Van Veen grab, and collected macrofauna were sedated and preserved pending analysis. In the laboratory, macrofauna were identified to finest taxonomic resolution possible under dissecting and compound microscopes, and enumerated. Sediment samples for physico-chemical analyses were kept frozen pending analysis. Up to 187 species belonging to 137 genera and 105 families were identified. Univariate community parameters such as abundance and number of species varied significantly along-shore, generally increasing towards less wave-exposed sites. Multivariate analyses revealed that community assemblages were heterogeneously distributed along-shore, corresponding to areas where anthropogenic influences such as effluent discharge and commercial harbour activities prevailed. During the 2008 survey, species assemblages separated into six groups corresponding to the six sites but xvii during the 2009 survey, species assemblages separated into four groups probably due to changes in environmental parameters such as the hydrodynamic regime. In both surveys the assemblage opposite a drainage canal (Papenkuils outfall) was distinct as it was dissimilar to all other assemblages. This site was also heterogeneous over relatively small spatial scales. Important physico-chemical variables influencing community structures during the 2008 survey included bottom measurements of temperature, salinity, dissolved oxygen, coarse sand and mud. During the 2009 survey, only bottom temperature and mud content were identified as important physico-chemical variables structuring community assemblages. The principal variable was probably the hydrodynamic regime, driving community structure at a larger scale in Algoa Bay. On a localised scale, communities were probably structured by other factors such as effluent discharges, influence of estuary mouths and activities associated with the harbour. With a lack of information on keystone species (regarded as good monitoring species) in Algoa Bay, it was proposed that groups that cumulatively comprise 50–75 percent of total abundance within communities be monitored annually. Included are amphipods, polychaetes, cumaceans, ostracods, tanaids and bivalves. It was also proposed that areas opposite estuary mouths, effluent outfalls and the dredged spoil dumpsite be monitored. This routine monitoring programme should be accompanied by periodic hypothesis driven research to assess the importance of stochastic events (e.g., upwelling) on macrozoobenthic community dynamics. Keywords: macrozoobenthos, soft-bottom, community assemblages, spatial distribution patterns, environmental drivers, long-term monitoring framework.
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Hammond, Julian. "Epizoan interactions in the chalk benthos". Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.279744.
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Wattimena, Stephen. "Couplage pelagos-benthos en Manche occidentale". Brest, 2000. http://www.theses.fr/2000BRESA001.
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Calabretta, Christopher John. "Benthic macrofauna in Narragansett Bay, Rhode Island : an examination of factors causing variability in community structure /". View online ; access limited to URI, 2009. http://digitalcommons.uri.edu/dissertations/AAI3378083.
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CAVALCANTI, Thaynã Ewerlin Ribeiro. "Briozoofauna associada às esponjas em ambientes recifais (Pernambuco, Brasil)". Universidade Federal de Pernambuco, 2016. https://repositorio.ufpe.br/handle/123456789/17960.
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Briozoários são organismos sésseis e coloniais, que dependem de uma superfície firme para assentamento larval e crescimento da colônia. Entre os diferentes substratos disponíveis para briozoários, as esponjas podem oferecer uma superfície favorável, trazendo muitas vantagens como a presença de compostos químicos que inibem a predação. Este estudo verificou a presença de briozoários em seis espécies de esponjas, com finalidade de avaliar a abundância e riqueza desses briozoários em diferentes esponjas. Três espécimes das esponjas, Amphimedon compressa Duchassaing & Michelotti, 1864, Amphimedon viridis Duchassaing & Michelotti, 1864, Desmapsamma anchorata (Carter, 1882), Dysidea etheria de Laubenfels, 1936, Haliclona implexiformis (Hechtel, 1965) e Tedania ignis (Duchassaing & Michelotti, 1864) foram coletadas mensalmente entre setembro de 2014 e fevereiro de 2016, em Pontas de Pedra, Pernambuco, Brasil. Os briozoários encontrados foram identificados até o menor nível taxonômico possível e quantificados. Um total de 324 espécimes de esponjas foi analisado, no qual destas 88 apresentavam briozoários em sua superfície (27%). Onze espécies de briozoários pertencentes à Classe Gymnolaemata foram encontrados nas esponjas, sendo quatro pertencentes à Ordem Ctenostomata, Amathia distans Busk, 1886, Amathia verticillata (delle Chiaje, 1822), Amathia vidovici Heller,1867 e Nolella stipata Gosse, 1855, sete da Ordem Cheilostomata, Beania klugei Cook, 1968, Catenicella uberrima (Harmer, 1957), Caulibugula dendograpta (Waters, 1913), Licornia sp., Savignyella lafontii (Audoin, 1826), Synnotum aegyptiacum Canu & Bassler, 1928 e Thalamoporella floridana Osburn, 1940. Briozoários foram abundantes nas esponjas Te. ignis e De. anchorata e pouco frequentes em Ap. compressa e Ap. viridis. Desmapsamma anchorata e Te. ignis apresentaram a maior riqueza de espécies (nove espécies em cada esponja), seguida por Dy. etheria (sete espécies). Uma baixa riqueza de espécies foi observada em Ap. compressa, com apenas três espécies de briozoários, Ap. viridis com quatro espécies, e H. implexiformis com cinco espécies. Apenas o briozoário N. stipata foi encontrado em todas as espécies de esponjas, enquanto que At. distans e At. vidovici não foram encontradas apenas em Ap. compressa. Uma maior riqueza e abundancia de briozoários foram encontradas em De. anchorata e Te. ignis, que apresentam superfície lisa e aveludada, e lisa e vilosa, respectivamente. Por outro lado, superfície lisa também é característica das espécies Ap. compressa e Ap. viridis, que apresentaram a menor frequência e diversidade de briozoários. Adicionalmente, as esponjas De. anchorata e Dy. etheria que apresentam superfície lisa e conulosa, respectivamente, compartilharam grande parte das espécies encontradas. A presença de metabólitos secundários nas esponjas do gênero Amphimedon que apresentam toxicidade já descrita na literatura, pode ter influenciado na ocorrência dos briozoários. Enquanto que as esponjas Te. Ignis, De. anchorata e Dy. Etheria, que apresentaram uma grande abundância de briozoários, podem ter provido um microhabitat adequado para os briozoários da região. O padrão temporal de ocorrência dos briozoários nas esponjas durante os 18 meses de coleta foi aleatório. O presente trabalho permite identificar alguns padrões da ocorrência dos briozoários, relacionado a composição química das esponjas e sua posição no substrato.
Bryozoans comprise sessile, colonial organisms that require a hard surface for settlement and growth. Among different substrata for bryozoans, sponges may provide suitable substrata, with advantages such as presence of compounds against predators. This study analyses the bryozoan community on six sponges species throughout 18 months, to evaluate the presence of bryozoans on its surface. Three specimens of each sponges, Amphimedon compressa Duchassaing & Michelotti, 1864, Amphimedon viridis Duchassaing & Michelotti, 1864, Desmapsamma anchorata (Carter, 1882), Dysidea etheria de Laubenfels, 1936, Haliclona implexiformis (Hechtel, 1965) and Tedania ignis (Duchassaing & Michelotti, 1864), were taken monthly betweem September 2014 to February 2016, in Pontas de Pedra, Pernambuco State, Brazil. Bryozoans were identified to the lowest taxonomic level, and quantified. Total of 324 specimens of sponges were analysed, 88 from those were found bryozoans on its surface (27%). Eleven gymnolaemate bryozoans were found on sponges being four of the Order Ctenostomata, Amathia distans Busk, 1886, Amathia verticillata (delle Chiaje, 1822), Amathia vidovici Heller,1867 and Nolella stipata Gosse, 1855, and seven species Cheilostomata, Beania klugei Cook, 1968, Catenicella uberrima (Harmer, 1957), Caulibugula dendograpta (Waters, 1913), Licornia sp., Savignyella lafontii (Audoin, 1826), Synnotum aegyptiacum Canu & Bassler, 1928 and Thalamoporella floridana Osburn, 1940. Bryozoans were considered abundant on the sponges Te. ignis and De. anchorata, but few frequents on Ap. compressa and Ap. viridis. On De. anchorata and Te. ignis were found the highest bryozoan richness (9 species of bryozoan per sponge species), followed by Dy. etheria (7 bryozoan species). A low species richness was observed in Ap. compressa, Ap. viridis and H. implexiformis with respectively three, four and five species of bryozoans on their surface. Only N. stipata was found on the six sponge species, while At. distans and At. vidovici were not found only on Ap. compressa. Higher richness and abundance of bryozoans were found in De. anchorata and Te. ignis, with smooth and velvety surface, smooth and villous surface, respectively. Smooth surface is also characteristic of Ap. compressa and Ap. viridis, with the lowest frequency and diversity of bryozoans. Additionally, on sponges De. anchorata and Dy. etheria, with smooth and conulose surface respectively, were shared the majority of bryozoan species. We suggest the presence of secondary metabolites may have interfered the bryozoans on sponges of Amphimedon genus. Sponges Te. ignis, De. anchorata and Dy. etheria, have an abundance of bryozoans; thus, we suggest these sponges may allow a suitable substratum for the bryozoans. The temporal variation of bryozoans on sponges was random. In present work some patterns of occurrence of bryozoans are presented, with relation to the chemical composition and position of sponge.
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Kilgour, Bruce William. "Fish-benthos correlations and effects on benthos that reflect significant effects on fish communities in southern Ontario streams". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/nq22213.pdf.
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Johnson, Gareth Edward Luke. "Facilitation and biodiversity in the marine benthos". Thesis, Bangor University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516111.
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Bustos-BaÌez, Silvana Noemi Raquel. "Recovery patterns of the North Sea benthos". Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289172.
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Shires, Rizpah. "The taxonomy, morphology and ecology of novel deep-sea agglutinated foraminifers in the Northeast Atlantic". Thesis, University of Reading, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386542.
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Murray, Fiona. "Functional contributions of benthic invertebrates to ecosystem process and functioning". Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=201938.
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Many of the processes on earth which are essential for sustaining life are driven by biological systems and it is functional diversity aswell as species richness which determines the health and sustainability of ecosystems. Ecosystem functions, from primary production to decomposition, are determined by the interactions both between organisms and between organisms and their environment. As such, there has long been an appeal in classifying species by their roles in ecological communities rather than by taxonomic groupings. However, there is often a disconnect between the criteria used to classify species into functional groups, often common morphological attributes, and the effect that the organisms within those groups have on specific ecosystem functions as the appropriateness of the classification criteria is rarely empirically tested. This thesis investigates inter- and intra-species variation in benthic invertebrates with respect to their effects on ecosystem processes (particle reworking and bioirrigation) and functions (nutrient cycling) and considers whether species can be grouped for single and multiple ecosystem functions in different environmental contexts. Overall the results show that species can be grouped by their effects on specific single ecosystem functions, but that these groups cannot be applied across multiple functions and processes. Further they show that species’ contributions to ecosystem functions change with environmental context (salinity, organic enrichment, seawater acidification and temperature), and that changes in the ecosystem processes known to mediate functions do not necessarily reflect a change in functioning. In addition intra-species variation in functional activity indicates that it may not be appropriate for all members of a population to be ascribed to the same functional group. This thesis highlights a need to test that different functional groups reflect different effects on ecosystem functioning. Further it shows that functional groups are not constant, individuals within populations are not necessarily functional equivalents, and that individuals have the capacity to change their contributions to ecosystem functions and processes. Future research needs to acknowledge and incorporate both biotic and abiotic sources of variability in species effects on ecosystem functions and processes.
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Mäkelä, Anni. "Diversity and functioning of Arctic benthic ecosystems and their resilience to climate change driven alterations in food supply". Thesis, University of Aberdeen, 2017. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=231760.
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Climate change is rapidly reducing the Arctic Ocean summer sea ice cover, consequently altering the patterns of primary production, with reducing ice algal-, but increasing phytoplankton primary production. As benthic consumers rely on the sinking phytodetritus for food, changes to food availability could render the benthos vulnerable if they prefer ice algae as a food source. The aim this thesis was to investigate the benthic macroinfaunal dietary reliance on ice algae and phytoplankton in North Water Polynya (NOW) and Lancaster Sound (LS) in Canadian Arctic Archipelago, and how a shift from one food source to another impacts the benthic community resource utilisation and nutrient cycling processes. I hypothesised that ice algae would be preferentially consumed and respired by the benthos. Natural abundance stable isotope analysis showed that phytoplankton is the main food source for macroinfauna in NOW and LS. 13C-15N isotope tracer experiments showed that while in NOW the accumulative macroinfaunal uptake of ice algal C was higher than uptake of ice algae, in LS more ice algal C and N was consumed. None of the major taxonomic groups exclusively preferred ice algae. No difference in bacterial uptake of the two algal types was observed at either site, but the respiration of phytoplankton C was significantly higher than respiration of ice algal C. The processing rates of phytoplankton-derived C were 39–46% higher than processing rates of ice algal C. Therefore, the hypothesis of ice algal preference by benthos must be rejected. I conclude that benthic macroinfauna exhibit great dietary flexibility, making them resilient against climate mediated changes in food sources, and that increasing availability of phytoplankton food can benefit the benthos in the future. Additionally, the transition from ice algae to phytoplankton dominated food can significantly enhance benthic organic matter processing, and especially respiration, rates in the future.
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Grigg, Nicola Jane. "Benthic bulldozers and pumps : laboratory and modelling studies of bioturbation and bioirrigation /". View thesis entry in Australian Digital Theses Program, 2003. http://thesis.anu.edu.au/public/adt-ANU20060228.104425/index.html.
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Wilkinson, Stephen Brian. "The ecology of the benthos in Liverpool Docks". Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261963.
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A broadscale survey of the benthos was carried out in the docks around Liverpool and the results indicated that the walls of the majority of the South Docks were dominated by Mytilus edulis. This species tended to be less abundant in docks close to the intake from the Mersey while Molgula manmattensis tended to be more abundant at these sites. These differences may be due to a combination of either increased suspended solids or decreased phytoplankton. The walls of Albert, Queens and Princes Docks were surveyed over a three year period. The results indicated that the abundance of Mytilus was relatively constant between years. Other more ephemeral species, such as Ciona, showed considerable variation both within and between years. Closer examination of the Mytilus population structure has indicated that it was dominated by one or two cohorts which had settled in 1988 - 1989. Much less recruitment has occurred subsequently. Reasons for this lack of recruitment are examined, however, the most likely explanations are increased predation from Carcinus and/or intraspecific interactions from the adult bed, either filtering out Mytilus larvae or reducing food supply to new settlers. Monitoring of the zooplankton indicated considerable temporal and spatial variation, despite the fact that the docks are effectively a closed ecosystem. The observed variations are attributed to either adult or larval behaviour or changes in primary production affecting secondary production. Tiles have been used to follow the pattern of annual succession and the effect of timing of available space on this pattern of succession. Results were integrated with changes observed in the wall benthos and variations in larval supply. Considerable differences were observed in the community that developed on suspended tiles, tiles fixed to the dock wall and cleared areas of the dock wall. One of the primary factors affecting this was thought to be reduced food supply on the wall due to the dense filter feeding assemblage there. No evidence was found of any strong interspecific interactions in the successional sequence. Rather, the community composition was typical for the time of year. The community development is described with regard to the life-history strategies of the species in the fouling assemblage. Tiles were also used to look at the annual pattern of algal settlement. This indicated that diatoms were the principal settlers early in the year, brown ephemerals such as Giffordia and Punctaria during spring and green ephemerals such as Enteromorpha and Cladophora over the summer period. Amphipods were the dominant grazers of this assemblage. Tiles left in place for two to three months initially developed dense algal growth but this was subsequently replaced by a cover of Botryllus. This change was thought to be accelerated by the grazing amphipods. No perennial algae were recorded in the docks; reasons for this are proposed. Finally, an assessment is made of the overall stability of the benthic ecosystem found in the docks around Liverpool and a number of possible management options, which could be used to improve the stability, are suggested.
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Erwin, David George. "Strangford Lough benthos and the marine community concept". Thesis, Queen's University Belfast, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.328081.
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Clare, D. S. "Causes and consequences of variability in marine benthos". Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3000512/.
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The last two decades have seen a shift of emphasis in ecology; from a focus on the drivers of biodiversity change toward a consideration for its effects on ecosystem functioning. Ecosystem functioning is affected by individual species (i.e. species with functionally dominant biological traits), but can also be influenced by other factors, such as interspecific interactions. Current evidence suggests that biotic influence over marine ecosystem functioning is largely underpinned by the effects of individual species. However, there are indications that this might not constitute a complete understanding of the link between marine biodiversity and ecosystem function (BEF). For this thesis, I applied our current understanding of marine BEF relationships (i.e. the causal link between particular biological traits and particular ecological functions) to long-term benthic community time series and investigated the causes of ecological change and its consequences for ecosystem functioning. A shift in the taxonomic composition of the species assemblage was explained by underlying variation in extrinsic drivers. However, the long-term conservation of trait composition suggests that functioning can be sustained in the face of environmental and ecological change. Experiments conducted to test BEF relationships in intertidal marine benthos reaffirmed the functional importance of the biological traits of species, but also showed that interactions among species can influence the delivery of ecological functions in various ways, including facilitation (i.e. function delivery is enhanced) and antagonism (i.e. function delivery is reduced). The results suggest that biotic influence over marine ecosystem functioning is more complex than previously suggested, and that the impacts of biodiversity change (e.g. species extinctions or shifts in species densities) could be either exacerbated or mitigated depending on the composition of the affected assemblage and the ecological function considered. To produce more realistic results, future indirect assessments of ecosystem functioning would benefit from incorporating interactions among species as well as their biological traits.
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Griffiths, Huw James. "Zoogeographic and richness patterns in Southern Ocean benthos". Thesis, Open University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.524788.
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Fortuna, Monique D'Assunção [UNESP]. "Controle descendente da meiofauna pelo caranguejo Uca burgersi". Universidade Estadual Paulista (UNESP), 2014. http://hdl.handle.net/11449/123765.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
A estrutura e funcionamento das comunidades naturais são regulados pela disponibilidade de recursos (controle ascendente) e predação (controle descendente). Os caranguejos do gênero Uca são comuns em áreas entremarés tropicais e subtropicais. Neste estudo avaliamos experimentalmente o controle descendente de caranguejos chama-maré (U. burgersi) sobre a meiofauna, em particular os Nematoda, e o microfitobentos. O estudo foi realizado em microcosmos com exclusão de Uca, e com densidades de 5 e 10 caranguejos. O perfil de ácidos graxos de amostras do sedimento, hepatopâncreas e fezes do caranguejo foram avaliados para identificação de marcadores tróficos. O gênero Microlaimus sp foi o mais abundante. A densidade de Nematoda, avaliada no sedimento superficial (0,5 cm) foi maior em áreas de exclusão, assim como a riqueza de gêneros de Nematoda também foram maiores nos sedimentos disponíveis para o forrageamento, quando comparado aos pellets de alimentação. Não houve alteração da densidade dos Nematoda no estrato subsuperficial (5 cm). As concentrações de clorofila a no sedimento não foram alteradas pela presença dos caranguejos, e a biomassa microfitobêntica nos pellets de alimentação não diferiu da encontrada no sedimento. Foram encontrados ácidos graxos marcadores de diatomáceas (14:0 e 16:0), carnivoria (18:1n9) e plantas vasculares (18:2n6) no sedimento, no hepatopâncreas e nas fezes de chama-maré. A maior percentagem de indicador 18:1n9 em associação às densidades elevadas dos Nematoda em sedimento no tratamento de exclusão confirmam a predação e o controle descendente de U. burgersi sobre a meiofauna. Não foi registrada preferência por gênero de Nematoda consumido por chama-maré
FAPESP: 2013/14828-0
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Fortuna, Monique D'Assunção. "Controle descendente da meiofauna pelo caranguejo Uca burgersi". Botucatu, 2014. http://hdl.handle.net/11449/123765.
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Orientador: Tânia Marcia CostaCoorientador: Sérgio Antonio Netto
Banca: Thais Navajas Corbisier
Banca: Lucinana de Ávila Santos
Resumo: A estrutura e funcionamento das comunidades naturais são regulados pela disponibilidade de recursos (controle ascendente) e predação (controle descendente). Os caranguejos do gênero Uca são comuns em áreas entremarés tropicais e subtropicais. Neste estudo avaliamos experimentalmente o controle descendente de caranguejos chama-maré (U. burgersi) sobre a meiofauna, em particular os Nematoda, e o microfitobentos. O estudo foi realizado em microcosmos com exclusão de Uca, e com densidades de 5 e 10 caranguejos. O perfil de ácidos graxos de amostras do sedimento, hepatopâncreas e fezes do caranguejo foram avaliados para identificação de marcadores tróficos. O gênero Microlaimus sp foi o mais abundante. A densidade de Nematoda, avaliada no sedimento superficial (0,5 cm) foi maior em áreas de exclusão, assim como a riqueza de gêneros de Nematoda também foram maiores nos sedimentos disponíveis para o forrageamento, quando comparado aos pellets de alimentação. Não houve alteração da densidade dos Nematoda no estrato subsuperficial (5 cm). As concentrações de clorofila a no sedimento não foram alteradas pela presença dos caranguejos, e a biomassa microfitobêntica nos pellets de alimentação não diferiu da encontrada no sedimento. Foram encontrados ácidos graxos marcadores de diatomáceas (14:0 e 16:0), carnivoria (18:1n9) e plantas vasculares (18:2n6) no sedimento, no hepatopâncreas e nas fezes de chama-maré. A maior percentagem de indicador 18:1n9 em associação às densidades elevadas dos Nematoda em sedimento no tratamento de exclusão confirmam a predação e o controle descendente de U. burgersi sobre a meiofauna. Não foi registrada preferência por gênero de Nematoda consumido por chama-maré
Abstract: Not available
Mestre
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Wildsmith, Michelle Deanne. "Relationships between benthic macroinvertebrate assemblages and habitat types in nearshore marine and estuarine waters along the lower west coast of Australia /". Access via Murdoch University Digital Theses Project, 2007. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20081029.93910.
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Schaeffer, Mary Alice. "Effects of land use on oxygen uptake by microorganisms on fine benthic organic matter in two Appalachian mountain streams". Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-12162009-020244/.
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Long, William Christopher. "Hypoxia and Macoma balthica : ecological effects on a key infaunal benthic species /". W&M ScholarWorks, 2007. http://www.vims.edu/library/Theses/Long07.pdf.
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Ford, Zackary L. "Impacts of suspended and deposited sediment on benthic invertebrates and fishes in a Missouri Ozark stream". Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4550.
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Thesis (M.S.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 7, 2007) Includes bibliographical references.
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Peck, Mika Robert. "A site-specific tropical sediment toxicity test using Chironomus crassiforceps to investigate metal bioavailability in acid-sulphate sediments". Thesis, University of Stirling, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341247.
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Young, Jade L. "Benthic macroinvertebrate assessment of Jones Creek, Dickson County, Tennessee a thesis presented to the faculty of the Graduate School, Tennessee Technological University /". Click to access online, 2009. http://proquest.umi.com/pqdweb?index=12&did=1908035881&SrchMode=1&sid=1&Fmt=6&VInst=PROD&VType=PQD&RQT=309&VName=PQD&TS=1264176435&clientId=28564.
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Hilderbrand, Robert Howard. "Relations between large woody debris, physical habitat, and benthic macroinvertebrates in Appalachian mountain streams". Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06082009-170744/.
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Draheim, Robyn C. "Tidal Freshwater and Oligohaline Benthos: Evaluating the Development of a Benthic Index of Biological Integrity for Chesapeake Bay". W&M ScholarWorks, 1998. https://scholarworks.wm.edu/etd/1539617733.
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Jones, Diane Elizabeth. "Functional ecology of the marine benthos : do species matter?" Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534000.
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Rydin, Mikael. "Effekt av fin ved (Salix sp.) på drift i semi-naturliga bäckar". Thesis, Karlstads universitet, Institutionen för miljö- och livsvetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-37836.
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In streams, wood provides protection, food and substrate for benthic macroinvertebrates, which leads a higher density and diversity of the benthic fauna compared to streams without wood. To examine wood and its effect on drift of macroinvertebrates an experiment was done in 18 sections of six semi-natural streams where fine woody debris (Salix sp.) was added to half of the sections (1-2 per stream). The purpose was to investigate possible differences in density and diversity of macroinvertebrates aswell as to investigate if there was any effect of location, upstream or downstream, in the streams. The results showed no significant effect of woody debris on total drift. The lack of an effect is probably related to the high abundance of predators (fish, brown trout) and the time of the day when the samples were taken. There was a significant effect of time on total drift; with more drift in September than in October. An effect of time was also found for the taxon Diptera (Chironomidae not included), with drift decreasing with temperature over the season.Ved i ett vattendrag ger skydd, föda och substrat åt bentiska makroevertebrater, vilket leder till en högre täthet och diversitet av makroevertebrater än i vattendrag utan ved. För att undersöka vedens inverkan på makroevertebraternas drift utfördes ett experiment i sammanlagt 18 inhägnader i semi-naturliga bäckar där hälften av inhägnaderna behandlades med fin ved (Salix sp.). Syftet var att undersöka eventuella skillnader i täthet och diversitet av makroevertebrater samt om det fanns en skillnad i läge, uppströms och nedströms i bäckarna. Resultatet visade ingen signifikant effekt av ved med avseende på den totala driften. Det fanns heller ingen signifikant effekt av ved på tätheten i enskilda på ved än utan. De bakomliggande faktorerna till varför ingen signifikant effekt av ved visades är troligtvis den höga tätheten av predatorer (öring) och tidpunkten då proverna togs. Det fanns dock en signifikant effekt av tid gällande den totala driften, i september var det mer drift än i oktober. Det fanns även en signifikant effekt av tiden på Diptera (alla Diptera taxa förutom Chironomidae). Detta tros vara på grund av den sjunkande temperaturen mellan månaderna.
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Alitto, Renata Aparecida dos Santos 1986. "Biodiversidade dos Echinodermata da Baía do Araçá, São Sebastião, SP". [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/315302.
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Orientador: Michela BorgesDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: Com o propósito de estudar a biodiversidade dos Echinodermata da Baía do Araçá, São Sebastião (SP), foi analisado o material procedente do Projeto Biota/FAPESP- "Biodiversidade e funcionamento de um ecossistema costeiro subtropical: subsídios para gestão integrada", Proc. nº 2011/50317-5. Para avaliação da diversidade e densidade desses organismos foram realizados: (i) inventário dos Echinodermata; (ii) estudos taxonômicos morfológicos com descrições detalhadas e discussões específicas para Ophiuroidea, incluindo ilustrações e fotomicrografias das espécies e ampliação das descrições já existentes e (iii) estudo dos fatores que influenciam a riqueza e abundância desses animais em microescala. Os equinodermos foram amostrados na região entremarés até 23 m de profundidade, costões rochosos, e como fauna associada a esponjas. Dos 863 exemplares coletados, foram identificadas quatro classes, 13 famílias, 19 gêneros e 25 espécies, o que corresponde a 8,3 % dos equinodermos registrados para o litoral brasileiro. A classe Ophiuroidea foi a mais diversa com 16 espécies e duas delas representam novos registros para a Baía: Amphiura kinbergi e Ophiothela danae. Para as espécies de ofiuróides, foi realizado um estudo taxonômico mais aprofundado com descrições da morfologia externa e interna (ossículos braquiais), o que enriqueceu as descrições já existentes. A maior riqueza e abundância deste grupo foi verificada no infralitoral quando coletado com draga. Amphiuridae e Ophiactidae foram as famílias mais representativas e corresponderam a aproximadamente 80 % do total de ofiuróides amostrado. Os resultados obtidos com esse trabalho contribuirão de forma consistente para o conhecimento da biodiversidade dos equinodermos no Estado de São Paulo, será a base para futuros monitoramentos sobre o impacto das atividades humanas na baía e seu entorno e contribuirá para implementações de ações de conservação deste rico ambiente
Abstract: The aim of the present work is to study the biodiversity of Echinodermata from Araçá Bay, São Sebastião (SP). We analyzed the material from Biota Project / FAPESP - "Biodiversity and functioning of a subtropical coastal ecosystem: a contribution to integrated management", Proc. No 2011 / 50317-5. Diversity and density avaliations of these organisms were performed to: (i) build an inventory of Echinodermata; (ii) morphological taxonomic studies with detailed descriptions and specific discussions to Ophiuroidea, including illustrations and photomicrographs of species and expansion of existing descriptions and (iii) study the factors that influence the richness and abundance in microscale. The echinoderms were sampled in the intertidal zone to 23 m deep, rocky shores, and as associated fauna of sponges. The 863 specimens collected were classified into four classes, 13 families, 19 genera and 25 species, corresponding to 8.3 % of echinoderms registered for the Brazilian coast. The Ophiuroidea was the most diverse with 16, with two being are new records for the Araçá Bay: Amphiura kinbergi and Ophiothela danae. For species of brittle stars, there was a further taxonomic study with descriptions of external and internal morphology (arm ossicles), that enriched the existing descriptions. The highest richness and diversity of this group was observed in infralitoral when collected with a dredge. Amphiuridae and Ophiactidae were the most representative brittle stars families and accounted for approximately 80 % of brittle stars sampled. The results of this work will contribute consistently to the knowledge of the echinoderms diversity in São Paulo, will be the basis for future monitoring of the human activities impact on the bay will contribute to this rich conservation actions implementations environment
Mestrado
Biodiversidade Animal
Mestra em Biologia Animal
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McChesney, Stephen. "The benthic invertebrate community of the intertidal mudflat at the Mai Po Marshes Nature Reserve, with special reference to resources for migrant shorebirds /". Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18061977.
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Allan, Elizabeth Louise. "Trophodynamics of the benthic and hyperbenthic communities inhabiting the Sub-Antarctic Prince Edward Islands : stable isotope and fatty acid signatures". Thesis, Rhodes University, 2011. http://hdl.handle.net/10962/d1006350.
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The aim of this study was to investigate spatial changes in the trophic and energy pathways of the benthic community in the shallow shelf waters of the sub-Antarctic Prince Edward Islands (PEI). A combination of stable isotope and fatty acid analyses were used to provide a time-integrated view of the assimilated feeding history of selected components of the PEI benthic community. This study forms part of the larger project entitled “Variability in the Southern Ocean ecosystems” and is a contribution to the South African National Antarctic Programme (SANAP). During austral autumn 2009, benthic specimens were collected from 10 stations (from depths of 70 to 295 m) in different regions around the PEI: inter-island shelf (upstream, between and downstream of the islands) and nearshore. Historical data were combined with new data collected during 2009 to assess the long-term trends in the feeding ecology of the benthos in the region of the islands. The stable isotope and fatty acid signatures of the benthic suspension- and deposit-feeding organisms generated during this study suggested that these two communities incorporated both phytoplankton and kelp in their diets. Stable isotope, and to a lesser extent fatty acid signatures, indicated that kelp contributed more to the diets of those organisms in close proximity to the kelp beds (nearshore stations) than those from the inter-island region. Overall, however, pelagic phytoplankton was the dominant food source in the diets of all organisms, even for those living near the kelp beds. Notable exceptions were the sponges and bryozoans, in which kelp and phytoplankton contributed similar proportions to their diets, most likely resulting from a size restricted feeding mode. There were, therefore, no distinct spatial differences in the importance of the various food sources. However, fatty acid compositional data indicated increased food quality between and within the lee of the islands compared to upstream. The organisms collected upstream of the PEI had substantially lower quantities of total fatty acids (TFAs) than organisms of the same species collected from nearshore, open shelf or downstream stations. The increased food quality between and within the lee of the islands was likely a result of the “island mass effect”, which reflects increased phytoplankton concentrations at the PEI. The fatty acid profiles of hyperbenthic shrimp Nauticaris marionis, a key species in the PEI ecosystem, revealed no distinct ontogenetic or spatial patterns. This result is in contrast to the stable isotope analyses, which detected both spatial and ontogenetic differences in the diet of the shrimp. Nearshore shrimp were more ₁₃C-enriched than those from the inter-island region, suggesting increased kelp entering the food web within these regions. In addition, the shrimps demonstrated enrichment in δ₁₃C and δ₁₅N signatures with an increase in size, resulting in a relatively distinct separation of size classes, thus reflecting niche separation through their diets. The fatty acid profiles revealed that the shrimp all contained large proportions of polyunsaturated fatty acids (PUFAs) and essential fatty acids (EFAs), indicating that the quality of food consumed was similar among size class and region despite the niche separation and variation in carbon sources utilised. In addition, diatom and dinoflagellate fatty acids (20:5ω3 and 22:6ω3, respectively) occurred in the highest proportions in N. marionis, highlighting the importance of phytoplankton (indirectly) in their diet. These results represent strong evidence that phytoplankton is an importance food source in the PEI ecosystem. The temporal investigation of isotope signatures in the benthos at the PEI indicated that N. marionis demonstrated an overall depletion in δ₁₃C signatures over the period of 1984 to 2009 (nearshore: -2.55 ‰, inter-island: -2.32 ‰). Overall, the benthic community showed similar depletions in δ13C signatures (from -1.96 to -4.70 ‰), suggesting that shifts have occurred in the carbon signatures at the base of the food web. The depletion in δ₁₃C signatures of the benthos at the PEI most likely reflects increased contributions of smaller slow growing phytoplankton cells (more depleted signatures than large fast growing cells) in the diets of these organisms over time. These diet shifts, in turn, suggest a decrease in productivity has occurred at the islands, likely due to a decreased frequency and intensity of the “island mass effect”. Decreased phytoplankton productivity at the PEI likely results from the southward shift in the average position of the sub-Antarctic Front (SAF), most likely in response to climate change, which in turn promotes flow-through conditions rather than retention at the PEI.
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Beghelli, Frederico Guilherme de Souza. "Caracterização da comunidade de macroinvertebrados bentônicos e fatores abióticos da represa de Itupararanga (Bacia do Alto Sorocaba, SP)". Universidade Federal de São Carlos, 2011. https://repositorio.ufscar.br/handle/ufscar/1510.
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Previous issue date: 2011-03-14Universidade Federal de Minas Gerais
The objectives of this work were the benthic macroinvertebrate community characterization from Itupararanga Reservoir, High Sorocaba Basin, SP, Brazil and the identification of the main abiotic factors wich affects the structure and distribution of those organisms. Samplings were taken with Van-Veen grab three times (cumulative samplings). The samplings were taken at three reservoir‟s zones: riverine zone, transitional and lacustrine ones and at two regions: litoral and central ones. Furthermore, it was taken samples during the wet (December 2009 and February 2010) and dry seasons (June and August 2010). The dissolved oxygen concentrations, electric conductivity, pH, transparency and depth near the bottom were reccorded in situ by using a multiprobe and Secchi disc in all sample points. With the objective to verify witch environmental variables would be the most important for the benthic macroinvertebrates community characterization, a correspondence canonical analisis (CCA) was done by the main taxa density logarithm and the water and sediment variables data matrix. The total number of reccorded taxa was 28. The Diptera family Chironomidae was the richest group (19 taxa). The Tubificinae (Clitellata, Naididae) were numerically dominants during the wet season and the Chironomidae (Diptera) were it during the dry one. Similarity analysis was performed in order to test the spatial heterogeneity hypotesis even in the longitudinal either in the transversal directions and the seasonly effects over the community. The results points to the occurrence of the spatial heterogeneity in both directions. So the reservoir diverges either in riverine, transitional and lacustrine zones, and central and litoral regions. The riverine zone is more distinctive than the others. This zone is characterized by having high nutrient concentrations (even in the water, either in the sediment) and coarse sediment. Moreover, the characteristic taxa are: Limnodrillus hoffmeisteri, Branchiura sowerbyi and Chironomus sp. It has high density values and dominance when compared to the other zones. The transitional and lacustrine zones presents some more intense transversal heterogeneity with more rich and diverse communities near the margins. It was noticed that the benthic macroinvertebrates responses to spatial gradient of environmental conditions in both senses, the longitudinal, and the transversal. Factors associated to environmental impacts and natural factors like granulometric sediment composition or depth can be determinants to the structure and composition of the community. The Itupararanga Reservoir is in eutrophication process and the riverine zone is the most affected area because it receives more directly the possible headwater impacts
Os objetivos deste trabalho foram a caracterização da comunidade de macroinvertebrados bentônicos da Represa de Itupararanga, Bacia do Alto Sorocaba, SP e a identificação de fatores abióticos determinantes da estrutura e distribuição destes organismos. Foram realizadas coletas com draga do tipo Van-Veen em triplicada (amostras cumulativas). As coletas foram realizadas em três zonas distintas da represa: zona de rio, zona de transição e zona de lago e em duas regiões: litoral e central. Além disso, foram realizadas duas coletas durante a estação chuvosa (dezembro de 2009 e fevereiro de 2010) e duas durante a estação seca (junho e agosto de 2010). Foram realizadas análises in situ de teor de oxigênio dissolvido, condutividade elétrica, temperatura, pH, transparência e profundidade d‟água próxima ao sedimento com a utilização de multisonda e disco de Secchi em todos os pontos amostrais. Em laboratório, foram determinadas as concentrações de fósforo total e clorofila a da subsuperfície a fim de se calcular o índice de estado trófico, em cada zona de amostragem. Com relação ao sedimento, foram determinados o teor de matéria orgânica, concentrações de fósforo e nitrogênio totais e composição granulométrica para todos os pontos amostrais. Com o objetivo de se verificar quais variáveis ambientais seriam mais importantes na caracterização da comunidade de macroinvertebrados bentônicos, foi realizada uma análise de correspondência canônica (ACC) a partir da matriz de dados da água e do sedimento e logarítimo da densidade de organismos dos principais táxons. No total foram registrados 28 táxons. A família de Diptera Chironomidae foi o grupo responsável pela maior riqueza (19 táxons). Os Tubificinae (Clitellata, Naididae) foram numericamente dominantes durante a estação chuvosa e os Chironomidae (Diptera) durante a estação seca. Foram realizadas análises de similaridade para se testar a hipótese de heterogeneidade espacial tanto no sentido transversal quanto longitudinal e efeitos da sazonalidade sobre as comunidades. Os resultados indicam haver a heterogeneidade espacial diferenciando a represa em zonas de rio, de transição e de lago, bem como em região litoral e central. A zona de rio diferencia-se mais intensamente das demais. Esta zona é caracterizada por maiores concentrações de nutrientes (no sedimento e na água) bem como por possuir sedimento mais grosseiro. Além disso, apresenta como táxons característicos Limnodrillus hoffmeisteri, Branchiura sowerbyi e Chironomus sp. Também caracteriza-se por elevados valores de densidade quando em comparação com os demais pontos amostrais e elevada dominância. As zonas de transição e lago apresentaram forte diferenciação transversal com comunidades mais ricas e com maior diversidade próximas às margens. Observou-se que os macroinvertebrados bentônicos respondem a um gradiente espacial de condições ambientais tanto no sentido longitudinal quanto transversal sendo que tanto fatores relacionados à impactos no ambiente quanto fatores naturais como composição granulométrica e profundidade podem ser determinantes na composição e estrutura da comunidade. A Represa de Itupararanga encontra-se em processo de eutrofização sendo que a zona de rio é a área mais afetada por receber diretamente os possíveis impactos a montante.
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Öberg, Jörgen. "Investigations of the influence of physical factors on some marine ecological systems /". Göteborg : Göteborg University, Dept. of Oceanography, 2005. http://www.gbv.de/dms/goettingen/492067244.pdf.
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Clarke, Dylan Thomas. "The relationship between sediment composition and infaunal polychaete communities along the southern coast of Namibia". Thesis, University of the Western Cape, 2005. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_8575_1253239169.
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This study examined the relationship between sediment structure and infaunal polychaete communities off the southern coast of Namibia from two separate sets of data, and a total of ninety-two samples. It also examined whether a selected group of organisms (polychaetes) could provide the same level of information regarding community structure, as the entire fauna, at a number of taxonomic resolutions.
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Clark, Robin Alexander. "Long term changes in the North Sea ecosystem". Thesis, University of Newcastle Upon Tyne, 2000. http://hdl.handle.net/10443/430.
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Long term data on the North Sea ecosystem are available for phytoplanktonic, zooplanktonic, berithic, fish, and seabird communities. Temporal changes in these have been examined by numerous researchers over the course of the 20th century, their main objective being to determine how the interannual dynamics of these communities are regulated. This study considers the long term ecosystem dynamics, and the mechanisms behind these dynamics, for the North Sea over the latter half of the 20th century, although it focuses upon the time series operated by the Dove Marine Laboratory, and the Continuous Plankton Recorder (CPR) survey in the central-west North Sea region. A review of the literature suggests that long term changes across the North Sea are ultimately driven by two processes. In the northern, western and central areas of the North Sea, the ecosystem is climatically driven, whilst in the southern and eastern regions, the signal of climate is masked by the large arithropogenic nutrient inputs into these regions. A comparison of the Dove and CPR zooplankton time series for the central-west North Sea area found that although their relative year to year fluctuations were similar, large differences were present in the absolute abundances recorded. Model derived catching efficiencies for the two sampling devices suggested that differences in absolute abundances were mainly due in some zooplankton taxa to a greater degree of active avoidance of the CPR sampling device. Further examination of these two series found that the long term zooplankton trends in the central-west North Sea were dissimilar to those observed for other North Sea regions. Inverse relationships between zooplankton abundance, and the position of the Gulf Stream North Wall, and with air temperatures were also observed. These dissimilar trends and inverse relationships were ultimately found to be due to the presence of an internal predation based mechanism. Cmatic influences were also found to indirectly influence the long term dynamics of the benthos in the central-west North Sea The primary factor influencing interannual variation in benthic abundance was phytoplankton productivity (Le. food), which in turn was related to climatic factors. However, at a second central-west North Sea benthic station, situated within a Nephmps norvegicus fishing ground, constant trawling disturbance of the benthos was the primary factor influencing both benthic abundance and species composition. Over the latter half of the 2O1 century, air temperatures and daily sunshine durations have increased in the central-west North Sea region, alongside changes in climatic proxy variables (e.g. NAO index). However, similar trends were not always observed in the biota. Ultimately, the long term dynamics of taxa, communities and ecosystems may be due to direct or indirect factors, yet interactions between a diversiy of internal and external factors, results in the complex behaviour of biological systems over time. This study shows that, a though the centralwest North Sea ecosystem is climatically driven, similar trends between climate and ecosystem components do not necessarily exist, and nor considenng the high comp exity of the ecosystem, should they be expected.
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Abdelrhman, Mohamed Abdalla. "The recognition of spatial and temporal structures in the Benthic boundary layer /". The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487262825075587.
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Libicki, Charles M. "Acoustic sensing of the vertical and temporal structure of sediment transport in the benthic boundary layer /". The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487267024997702.
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Hasemann, Christiane. "Kleinskalige Heterogenität in der arktischen Tiefsee : Einfluss kleiner Kaltwasser-Schwämme auf die Diversität benthischer Nematoden-Gemeinschaften = Small scale heterogeneity in the Arctic deep sea /". Bremerhaven : Alfred-Wegener-Inst. für Polar- und Meeresforschung, 2006. http://www.gbv.de/dms/bs/toc/513119086.pdf.
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Wall, Kara R. "Subtropical benthos vary with reef type, depth, and grazing intensity". Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6974.
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Marine epibenthic communities are influenced by both pre- and post-recruitment processes. For instance, the larval supply and cues that influence settlement (pre-recruitment), as well as the growth and mortality of individuals (post-recruitment), may differ across reef type and depth. Determining the relative influence of these processes is important to understanding how epibenthic communities can develop in a region. Using both a recruitment experiment that controlled grazing by urchins and in situ photographic surveys of epibenthic communities, this study examined the recruitment and composition of epibenthos on natural limestone and artificial reefs in the eastern Gulf of Mexico (eGOM). In the experiment, tiles that were open to urchin grazing had lower percent cover of algae (-12%) and higher cover of crustose coralline algae (CCA) (13%) than those that excluded urchins. Patterns in tile cover were likely the result of CCA either resisting grazing mortality or recolonizing exposed areas after algae were removed. Prevalence of estuarine species on inshore tiles was indicative of variation in recruitment across depth. Urchin density was positively correlated with the structural complexity of the habitats, which was higher on artificial reefs than natural ones, a factor that potentially had important effects on several observed patterns. Results from photographic surveys indicated that natural reef communities had higher algal cover and lower cover of invertebrates (e.g., corals and hydroids) than artificial reefs. These findings were consistent with previous work conducted in both temperate and tropical ecosystems, and suggested that grazing from urchins plays an important role in shaping epibenthic community structure in the subtropical eGOM.
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Fielding, Nicola Jane. "Fish and benthos communities in regenerated dock systems on Merseyside". Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.482788.
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Restored docks have high amenity, tourism and recreational value. Polluted and unaestheticw ater is a major factor potentially inhibiting redevelopmento f docklands, particularly if the source of water suffers from severe pollution problems. The aims were to examine spatial and temporal patterns of hydrography and ecology of Merseyside Docks. Strategies to develop benthic filter-feeders on both the walls and in the sediments were considered important in maintaining good water quality. In the South Docks, algal blooms were mainly small and short-lived and anoxia was infrequent. In Princes Dock (Central chain) water quality was very good. Morpeth Dock (Wirral chain) suffered from poor water quality. Anoxia resulted in high mortalities of dock fauna and fish and the release of hydrogen sulphide gas. Algal blooms were very large and were maintained over long periods. The dinoflagellate, Prorocentrum minimum, was particularly prevalent. Zooplankton have remained at relatively low densities in the South Docks, particularly in Albert Dock (South chain), probably because of strong competition for food with benthic filter-feeders. In contrast, Morpeth Dock has maintained much higher numbers, probably because of the plentiful food supply and absence of benthos. The benthos of the walls was surveyed. Mytilus edulis is most prominent in Albert and Queens Docks; Ciona intestinalis and Ascidiella aspera are most abundant in Albert and Princes Docks; and, Molgula manhattensis dominant in Brunswick and QueensD ocks. Tiles have been used to follow the pattern of annual successiona nd the effect of timing of available space on this pattern of succession. In contrast to previous years when there had been very little recruitment of Mytilus to the South Docks, Mytilus settlement occurred in Queens Dock during autumn 1995. Experiments aimed at increasing the filter-feeding capacity by introducing Cerastodermae dule (common cockle) and manipulating particle size of the sediment concluded that cockles do not survive in the dock, probably due to occasional low oxygenc on centrations in the hypolimnion, and modification of sediment has very little effect on natural colonization. Experiments examined the impact of filter-feeders on phytoplankton numbers and regeneration of nutrients. Mytilus was shown to have higher clearancer ates( cell mV h' int) than its major competitors( Ciona intestinalis, Styela plicata) on the dock wall. The experiment investigating nutrient release by Mytilus indicates release of phosphate. Fish communities in the South Docks were relatively diverse, with a total of fifteen species of fish being caught. The size/frequency analyses suggest that the majority of fish were juveniles. The occurrence of two sea trout (Salmo trutta) indicates a return of salmonids to the estuary. The use of a capacity model as a management tool is proposed; this has been fitted to the South Docks system with some success.
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Kopecki, Ianina. "Calculational approach to FST-hemispheres for multiparametrical Benthos Habitat modelling". [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-38677.
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Schaffner, Linda C. "Ecology of the benthos of the lower Chesapeake Bay (Maryland)". W&M ScholarWorks, 1987. https://scholarworks.wm.edu/etd/1539616841.
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The spatially complex lower Chesapeake Bay estuary is characterized by a variety of bottom types and hydrodynamic regimes. to account for this physically-induced variability a benthic habitat delineation scheme was developed based on existing knowledge of physical and geological characteristics. Within the context of this scheme a series of studies were conducted to identify biotic response to and interactions with the physical, chemical and geological gradients that characterize the lower Chesapeake Bay. These studies characterized organism distribution and abundance patterns within the lower bay and identified processes controlling those patterns. The biological community of the polyhaline basin habitat, an area characterized by moderate tidal, but little wave-induced bottom disturbance was defined and described for the first time. This community is characterized by large tube and burrow builders, epifaunal and commensal organisms, shallowly-distributed, short-lived species and deeply-dwelling predators. The basin is also the preferred habitat of overwintering blue crabs and an area where biotic sediment reworking generally exceeds physical reworking. The results of these studies suggest that within the lower Chesapeake Bay estuarine system, the relative importance of biological versus physical processes in maintaining the structure and dynamics of estuarine benthic communities will be greatest in the basin habitat.
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Boyd, Sheree. "Benthic invertebrate assemblages and sediment characteristics". Click here to access this resource online, 2009. http://hdl.handle.net/10292/727.
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Cold seep ecosystems in the deep sea are fuelled by chemosynthetic processes based on methane emission to the sediment surface from gas hydrate disassociation, methanogenesis or thermogenic processes. While cold seep ecosystems have been studied in the last three decades worldwide, little is known about New Zealand’s cold seep habitats and associated fauna. A joint German-New Zealand cruise to the Hikurangi Margin in early 2007 enabled biological and sediment sampling to investigate the biological and sedimentological relationships and variability of seeps and their faunal diversity. Multi-disciplinary approaches were employed that included Xray radiography, stratigraphic descriptions, lebensspuren traces analysis, sediment grain size analysis, determination of total organic content, carbonate content and its stable isotopic composition, and analysis of benthic invertebrate assemblages of seep habitats. The results of this study revealed three distinctive habitats and associated fauna based on the sediment characteristics and faunal type. Habitat 1 includes all sites pertaining to Omakere Ridge, a seep-related habitat comprised of layers of very poorly sorted, sandy silt, shell hash and bands of methane-derived authigenic aragonitic carbonate nodules with low total organic content (TOC). Due to the characteristics of the sediments and death assemblages of molluscs, it is inferred that Habitat 1 methane seepage is actively diffusive, waning or dormant. Habitat 2 describes sites that are either non-seep or relic and applies to those at Bear’s Paw and Kaka. Habitat 2 constituted of shell hash overlain with very poorly sandy silt, and low carbonates content and low to medium TOC. Habitat 3 describes non-seep related habitats, and includes all sites of the Wairarapa region and one reference site from Kaka also falls into this category. Sediments for Habitat 3 constituted poorly sorted silt with high TOC and low carbonate content which can be explained by their close proximity to land and converging sea currents. The mineral components of the background siliciclastic sediments for all sites studied originated in the Tertiary mudstone of the East Coast Basin. The characteristics of seep habitats of the Hikurangi Margin were comparable to that of the Northern Hemisphere modern seep counterparts, although the abundance and distributions of seep fauna were low. Results from this research have enhanced our understanding on the spatial and variability of methane fluxes and their affects on the duration of cold seep ecosystems, especially for New Zealand. However, more such studies are essential to increase our understanding of seep sediments and explain disturbance-sediment-benthic invertebrate interactions.
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Angulo, Preckler Carlos. "Biodiversity and Chemical Interactions in Antarctic Benthic Communities of Deception Island (South Shetland Islands) = Biodiversidad e Interacciones Químicas en las comunidades bentónicas Antárticas en Isla Decepción". Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/385350.
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This Thesis covers two different topics in Antarctic marine benthic invertebrates.
The two main goals are:
1) to improve the knowledge of the biodiversity of the shallow water benthic communities inside Deception Island (South Shetland Islands, Antarctica), and
2) to establish the chemical ecology of selected Antarctic organisms, by studying the antifouling and antimicrobial activity of their organic extracts.
Deception Island is an active volcano on the southwestern end of the South Shetland Island chain. This island chain parallels the northeastern curvature of the Antarctic Peninsula, but is separated from the Antarctic continent by the narrow Bransfield Strait. Volcanic activity is believed to be the key environmental component that controls epibenthic and infaunal invertebrate populations in Port Foster. Compared to nearby islands, Deception Island is clearly defaunate at depth, and since the last eruption in 1970, has been considerably recolonized. However, many taxa are still very poorly represented and the colonizer species are mainly those with planktotrophic larvae. Interestingly, the soft-bottom benthos communities of the shallowest zone of Port Foster has been barely and poorly explored yet. A complete study of the benthic invertebrate shallow community at Deception Island was conducted, looking for a comprehensive view of this singular spot working at different trophic levels. Shallow-water sediment at Deception Island is inhabited mostly by opportunistic, motile species, living under the influence of serious and long-lasting disturbances, related more to high sedimentation rates within the bay and the absent of hard substrata, than with the ice-scouring or anchor-ice disturbances (mostly absent inside the caldera, but common elsewhere in Antarctica). The trophic relationship between the water and benthic community has been described in four stages; (i) particulate matter is suspended from the seafloor into the water column; (ii) nutrients stimulate bacterial and phytoplankton production, which stimulates zooplankton production; (iii) large suspended particles provide food for planktonic and benthic grazers; and (iv) organisms no consumed sink to the seafloor to be utilized by benthic community. These nutrients would be transmitted to bacterial communities, known to use this abundant material over the year in some sites of the island. This microbial biomass could then be transmitted to the meiofauna, trophic level showing also high densities in Port Foster. Furthermore, Port Foster receives much runoff during the austral summer, and may serve as a “nutrient trap”, thus influencing the meiofaunal organisms. All these, together with the microbial communities, could be behind the high macrofaunal densities observed here. Finally, all these trophic compartments would then be supporting the remarkable density of megafaunal organisms at Port Foster.
Antarctic benthos is dominated by biological interactions, and it is expected that many marine invertebrates use chemicals as means of defense from predators, pathogens or preventing overgrowth. Natural products (also called secondary metabolites) are chemicals produced by organisms, which regulate the biology, co-existence, and co-evolution of the species without participating directly in their primary metabolism. The role of these natural products play in the Antarctic benthic communities is one of the main subjects of investigation in the present dissertation through an experimental contribution in the antimicrobial and antifouling field using chemical crude extracts from Antarctic benthic organisms. Marine secondary metabolites may play a role as deterrents against pathogenic microorganisms, fouling organisms, predators and/or competitors. Benthic marine organisms, under intense pressure for space, light and food, have developed a wide range of defensive mechanisms ranging from behavioral to physical and chemical strategies. Competition for space is a remarkable ecological force, comparable to predation that produce a strong selective pressure on benthic invertebrates. Some invertebrates, thus, possess antimicrobial compounds to reduce surface bacterial growth. The ubiquity of fouling organisms in the marine environment and the negative consequences of fouling are likely strong evolutionary pressures for marine organisms to develop defenses to protect their surface from fouling. In summary, marine invertebrates can survive in the highly competitive and hostile environments, mainly relying on their chemical defensive system by accumulating a series of defensive chemicals in their bodies or releasing the compounds to their surroundings.Isla Decepción es un volcán activo en el extremo suroeste de la cadena de islas Shetland del Sur. Esta cadena de islas discurre paralela a la curvatura noreste de la Península Antártica, pero está separada del continente antártico por el estrecho de Bransfield. Se cree que la actividad volcánica es el componente ambiental clave que controla las poblaciones de invertebrados epibentónicos e infaunales en Puerto Foster. En comparación con las islas cercanas, Isla Decepción está claramente depauperada en profundidad, y desde la última erupción en 1970, sus fondos han sido recolonizados progresivamente. Sin embargo, muchos taxones están poco representados y las especies colonizadoras son principalmente aquellas que tienen larvas planctotróficas. Curiosamente, las comunidades bentónicas de fondos blandos de la zona más somera de Puerto Foster apenas han sido estudiadas. En un contexto en que la Península Antártica está experimentando una de las tasas más rápidas de cambio climático regional en la Tierra, Isla Decepción se presenta como una buena oportunidad de trabajar con escenarios previsibles para las comunidades bentónicas antárticas costeras. Se ha realizado un estudio completo de la comunidad bentónica de invertebrados en aguas poco profundas de Isla Decepción, en busca de una visión integrada de este paraje singular estudiando diferentes niveles tróficos. El bentos antártico está dominado por interacciones biológicas, y es previsible que muchos invertebrados marinos utilicen productos químicos como medio de defensa contra los depredadores, contra patógenos o para evitar el recubrimiento (antifouling). El papel que estos productos naturales desempeñan en las comunidades bentónicas antárticas es uno de los principales temas de investigación en la presente tesis a través de una contribución experimental en el campo de los antimicrobianos y del antifouling utilizando extractos crudos de organismos bentónicos antárticos. Los invertebrados marinos pueden sobrevivir en entornos altamente competitivos y hostiles, confiando principalmente en su sistema defensivo químico mediante la acumulación de una serie de sustancias químicas defensivas en sus cuerpos o liberando los compuestos a su entorno.
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Magorrian, Bridgeen Helen. "The impact of commercial trawling on the benthos of Strangford Lough". Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318751.
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Tempera, Fernando. "Benthic habitats of the extended Faial Island Shelf and their relationship to geologic, oceanographic and infralittoral biologic features /". St Andrews, 2008. http://hdl.handle.net/10023/726.
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Soares, Alexandre Goulart. "Sandy beach morphodynamics and macrobenthic communities in temperate, subtropical and tropical regions : a macroecological approach". Thesis, University of Port Elizabeth, 2003. http://hdl.handle.net/10948/293.
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A comprehensive study involving 52 microtidal beaches spanning from reflective to dissipative states and located in tropical, subtropical and temperate regions in the Atlantic, Pacific and Indian oceans was carried out to unravel the relative roles of latitude and beach morphodynamics in determining beach macrobenthic species richness, abundance, biomass and mean individual body sizes. Since beach slope is one of the most important factors controlling beach fauna, a model based on beach geometry was applied to the sub-aerial beach deposit to understand the role of physical factors in predicting equilibrium beach slopes. Additionally, it was tested if the occurrence of beach types is related to latitude, and how physical factors change with morphodynamics and latitude. The beach morphometric model makes three assumptions: 1) that the cross-section of a beach deposit is equivalent to a right-angled triangle, 2) that the physical hydrodynamic factors (wave height and spring tide amplitude) and the beach deposit characteristics (sand grain size, beach slope and width) are interchangeable with their geometric counterparts producing an equation to explain beach geometry, and 3) that the predicted beach slope is in equilibrium with the hydrodynamic and sedimentological forces. The equation for predicting beach slope was derived and then tested against field data collected over 52 beaches. The predicted slopes were not significantly different from the observed slopes of the studied natural beaches. However some estimated slopes were different than observed ones. Possible sources of deviation between calculated and observed slopes may be the systematic sampling errors associated with field data. Alternatively, observed slopes could be the result of past hydrodynamic conditions, explaining the differences with the slopes calculated by the beach morphometric model, which assumes a state of equilibrium between beach slope and hydrodynamic conditions. A higher correlation of beach faunal structure with observed slopes rather than with present hydrodynamic conditions could then be indicative of faunal responses to previous hydrodynamic conditions in the same way was the observed slopes. The beach morphometric model could therefore be also useful in predicting faunal responses to changing hydrodynamic conditions. Since the model does not consider wave period, it is concluded that further tests should be done using laboratory and time-series field data and incorporating the role of wave period and beach permeability to ascertain its predictive value. Tropical regions had significantly more beaches in a reflective state than temperate and subtropical regions. Some tropical beaches were fronted by coral reefs, which not only provided coarse carbonate particles, but also additionally dissipated the low wave energy present in these climatic areas. Only one dissipative beach with high energy was found in the tropics, in southeast Madagascar. Temperate and subtropical regions, on the other hand, were dominated by dissipative beaches with medium to fine sands. Open oceanic reflective beaches were non-existent in the subtropics and rare in temperate regions, only occurring in estuaries, enclosed bays or on islands facing the continent. Intermediate beaches were more common in the subtropics but also occurred frequently in the other two regions, having higher energy in temperate regions. Reflective beaches had significantly steeper slopes, coarser sands, smaller waves and shorter swash lengths when compared to dissipative beaches. Additionally, reflective beaches were narrower, had deeper water tables and in consequence shorter saturation zones. Wave periods and surfzone widths were on average larger on dissipative than on reflective beaches. The frequency of occurrence of beach types is therefore related to the climatic signature of each latitude. Mid latitudes would be predicted to have more dissipative beaches with large and long waves because of their proximity to the storm generating belt around 50-60° S - these beaches will have a predominantly finer sands because of the input by rivers in rainy areas. Lower latitudes will have more reflective beaches due to a modal low energy wave climate and also because of the presence of inshore and offshore biotic structures such as coral reefs that dissipate even more the energy from the waves. Tropical and subtropical regions had larger marine species pools than temperate regions. After controlling for biogeographical differences in total species pool, dissipative beaches were on average significantly richer than intermediate and reflective beaches. Crustaceans were also more diverse on dissipative beaches, this difference being not significant for either molluscs or polychaetes. Significant relationships were found between total beach species richness (with or without terrestrial species), crustacean and mollusc species richness with beach morphodynamics as represented by the Dean’s index. Indices incorporating the role of tide, such as BSI, were less important in predicting species richness on the microtidal beaches studied here. Several other physical factors were also significantly correlated with species richness, the most important being the Beach Deposit Index, i.e. BDI, a composite index of beach slope and grain size. The highest correlation was between BDI and relative species richness, i.e. local beach species richness / regional species richness. Total regional marine species richness was higher in Madagascar and North Brazil (tropical beaches) than in Southeast Brazil (subtropical), or the West Coast of South Africa and South-Central Chile (temperate beaches). Not only was the pool of species capable of colonizing beaches richer in tropical and subtropical regions, but also local diversity of each morphodynamic beach type was higher among tropical beaches than their temperate counterparts. Although the results of this study agree with the predictions of the swash exclusion hypotheses, several reflective and intermediate beaches had higher species richness than predicted before and this seems to be linked to the presence of finer sediments and a less turbulent flow for larvae to settle. It is concluded that beach species richness is not necessarily controlled by one major morphodynamic parameter; this control is complex and probably involves multiple interacting biotic (biological interactions) and abiotic (e.g. grain size, wave height, beach slope and width, water table) factors. Species richness seems to be controlled on two different scales: on an evolutionary one where tropical and subtropical regions have higher regional and local diversity due to higher speciation rates; and on an ecological scale, where fine grained sand beaches have their carrying capacity enhanced by higher larval settlement rates and survival of recruits towards adulthood. On average dissipative beaches had higher total densities and macrofaunal abundances than reflective ones. Crustaceans, terrestrial species and cirolanid isopods such as Excirolana spp. were also more abundant on dissipative beaches. The difference was not significant for molluscs and polychaetes. Significant relationships were found between total abundance, crustacean species richness and beach morphodynamics as represented by the Dean’s index. Again, BSI was less important than individual physical factors in determining faunal abundance on the studied microtidal beaches. Several other physical factors were also significantly correlated with abundance, the most important being the Beach Deposit Index (BDI). The highest correlation was between BDI and total macrofaunal abundance. Factors related to surf zone processes, and possibly productivity, were highly correlated with total community, crustaceans, Excirolana spp. and terrestrial species abundances. The abundances of polychaetes and molluscs were better correlated with factors related to the beach deposit (BDI, slope, grain size and water table depth). Significant differences were observed between latitudinal regions for the average beach and also for each beach type. In general temperate beaches harboured larger community densities and abundances, and also crustacean, Excirolana spp. and terrestrial abundances. Mollusc and polychaete abundances were larger on subtropical and tropical beaches. The control of abundance on a sandy beach is complex and involves multifactorial processes at evolutionary and ecological scales. At evolutionary scales animals seem to attain higher abundances in the region where they first evolved, e.g. amphipods and isopods in temperate regions. At ecological scales they attain higher abundances where productivity is higher (total macrofaunal, crustaceans, Excirolana spp., terrestrial spp.) or where the settlement environment is more benign (molluscs and polychaetes). Dissipative beaches supported larger average and total community biomass than reflective beaches. Crustaceans, terrestrial species and cirolanid isopods such as Excirolana spp. also had larger biomass on dissipative beaches. The difference was not significant for molluscs and polychaetes. Significant relationships were found between the biomass of community and taxonomic groups with beach morphodynamics as represented by the Dean’s morphodynamic index. On the microtidal beaches studied here, BSI was less important than other morphodynamic indices and single physical factors in determining faunal biomass and mean individual body size. Surf zone characteristics such as wave height, period and surf zone width had the highest correlations with community, crustacean.