Дисертації з теми "Trophic flow"
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Ribeiro, Fabianne de Araújo. "Silver nanoparticles flow in an aquatic trophic chain." Doctoral thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/12478.
Повний текст джерелаSilver nanoparticles (AgNP) have been produced and applied in a variety of products ranging from personal care products to food package containers, clothing and medicine utilities. The antimicrobial function of AgNP makes it very useful to be applied for such purposes. Silver (Ag) is a non-essential metal for organisms, and it has been historically present in the environment at low concentrations. Those concentrations of silver increased in the last century due to the use of Ag in the photographic industry and lately are expected to increase due to the use of AgNPs in consumer products. The presence of AgNP in the aquatic environment may pose a risk for aquatic species, and the effects can vary from lethal to sublethal effects. Moreover, the contact of aquatic organisms with AgNP may not cause immediately the death of individuals but it can be accumulated inside the animals and consequently transferred within the food chain. Considering this, the objective of this work was to study the transfer of silver nanoparticles in comparison to silver ions, which was used as silver nitrate, within an aquatic food chain model. To achieve this goal, this study was divided into four steps: the toxicity assessment of AgNP and AgNO3 to aquatic test-species, the bioaccumulation assessment of AgNP and AgNO3 by Pseudokirchneriella subcapitata and Daphnia magna under different exposure scenarios, and finally the evaluation of the trophic transfer of Ag through an experimental design that included the goldfish Carassius auratus in a model trophic chain in which all the species were exposed to the worse-case scenario. We observed that the bioconcentration of Ag by P. subcapitata is mainly driven by ionic silver, and that algae cannot internalize these AgNPs, but it does internalizes dissolved Ag. Daphnia magna was exposed to AgNP and AgNO3 through different exposure routes: water, food and both water and food. The worse-case scenario for Daphnia Ag bioaccumulation was by the joint exposure of contaminated water and food, showing that Ag body burdens were higher for AgNPs than for AgNO3. Finally, by exposing C. auratus for 10 days through contaminated water and food (supplied as D. magna), with another 7 days of depuration phase, it was concluded that the 10 days of exposure were not enough for fish to reach a plateau on Ag internal concentration, and neither the 7 days of elimination were sufficient to cause total depuration of the accumulated Ag. Moreover, a higher concentration of Ag was found in the intestine of fish when compared with other organs, and the elimination rate constant of AgNP in the intestine was very low. Although a potential for trophic transfer of AgNP cannot be suggested based in the data acquired in this study, there is still a potential environmental risk for aquatic species.
As nanopartículas de prata (AgNP) têm sido produzidas e utilizadas em uma grande variedade de bens de consumo, desde produtos de higiene pessoal a embalagens de alimento e utensílios médicos. A ação antimicrobiana das nanopartículas de prata é o principal fator que as torna úteis e ideais para tais aplicações. A prata é um metal não essencial e pode ser encontrado no ambiente em concentrações ecologicamente irrelevantes. No passado, a atividade de revelação fotográfica era a principal fonte de prata no ambiente. Ultimamente, estas concentrações têm aumentado devido à vasta utilização das nanopartículas de prata na indústria. A presença da prata no ambiente pode constituir um risco para as espécies e os efeitos causados podem ser do tipo letal ou sub-letal. Para além disso, a exposição dos organismos à prata, mesmo que não os leve à morte imediata, pode causar uma acumulação deste metal, e que poderá ser transferido entre os níveis tróficos da cadeia alimentar aquática. Tendo isto em consideração, o objetivo deste trabalho foi estudar a transferência das nanopartículas de prata numa cadeia trófica aquática modelo, e comparar os mesmos processos com a exposição a nitrato de prata (AgNO3). Para alcançar este objetivo, este trabalho foi dividido em quatro estudos: avaliação da toxicidade das AgNP e do AgNO3 para as espécies em estudo, uma posterior avaliação da bioconcentração das AgNP e do AgNO3 pela alga verde P. subcapitata, o estudo da bioacumulação da prata em Daphnia magna, exposta a diferentes vias de contaminação (água, alimento e ambos) e por último a avaliação da transferência das AgNP e de AgNO3 através de um desenho experimental que incluiu o peixe Carassius auratus expostos a água e alimento contaminados. Os resultados obtidos com estes estudos indicam que a bioacumulaçãoo da prata na alga P. subcapitata ocorre devido à internalização dos iões de prata, e não das nanopartículas. Estas aparentemente encontram-se em aglomerados próximas às células das algas, não entrando nas células/algas. Relativamente à Daphnia magna, o maior fator de bioacumulação foi obtido quando estas foram expostas à água e alimento contaminados com AgNP. Finalmente observou-se que os peixes não atingiram um equilíbrio na concentração interna de prata, e que o órgão que apresentou maior bioacumulação de prata foi o fígado. Para além disso, foi verificada no fígado uma taxa de eliminação muito baixa, o que nos pode levar a sugerir que as nanopartículas de prata podem persistir neste órgão. Apesar de não se verificar um potencial para transferência trófica, as nanopartículas de prata podem representar risco para as espécies aquáticas aqui estudadas.
Whiting, Daniel P. "Macroinvertebrate production, trophic structure, and energy flow along a tallgrass prairie stream continuum /." Available to subscribers only, 2009. http://proquest.umi.com/pqdweb?did=1967802681&sid=3&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Повний текст джерелаWhiting, Daniel Philip. "MACROINVERTEBRATE PRODUCTION, TROPHIC STRUCTURE, AND ENERGY FLOW ALONG A TALLGRASS PRAIRIE STREAM CONTINUUM." OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/120.
Повний текст джерелаIwata, Tomoya. "The roles of fluvial geomorphology in the trophic flow from stream to forest ecosystems." 京都大学 (Kyoto University), 2003. http://hdl.handle.net/2433/86478.
Повний текст джерелаPavlaki, Maria. "Bottom-up contamination in marine systems: model trophic levels to predict cadmium flow in marine organisms." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16846.
Повний текст джерелаCadmium is considered one of the most toxic metals to aquatic organisms. This naturally occurring metal is found in the environment in low concentrations due to natural processes, such as volcanic eruptions, natural crust erosion and also anthropogenic activities, such as mining and smelting. As a by-product of zinc mining, cadmium can reach aquatic environment through leaching or to rainwater runoff from the mine areas. It is a non-essential metal for organisms that even at relatively low concentrations can be toxic and may cause adverse effects due to its high bioaccumulation tendency. Considering this, the objective of this work was to study the toxicity and bioaccumulation potential of cadmium within different model marine trophic levels. To achieve this goal, this work was divided into four studies: i) assess the eco- and genotoxicity of cadmium to three marine test-species, representing different marine trophic levels, ii) determine the bioconcentration potential of cadmium in the calanoid copepod Acartia tonsa under different environmental conditions, such as pH, salinity and temperature, iii) evaluate the uptake and depuration kinetics of cadmium by the estuarine ditch shrimp Palaemon varians considering three different uptake routes: water, diet, water + diet and iv) assess the bioaccumulation patterns of cadmium in the Senegalese sole Solea senegalensis, a final consumer, and the possible risk and implications the consumption of the edible fraction of both shrimps and fish may bear to human health upon Cd exposure. We observed that the toxicity of cadmium is highly influenced by its speciation. Highest sensitivity to cadmium was observed by A. tonsa while the most sensitive endpoint was the Larval Development Ratio (LDR). Cadmium induced DNA damage to all species with increasing concentrations. The bioconcentration of cadmium by A. tonsa is strongly affected by different environmental conditions due to biological processes. The simultaneous exposure of P. varians to cadmium-contaminated water + diet showed that cadmium internal concentration was higher when compared to the individual pathways. Finally, by exposing S. senegalensis for 14 days through contaminated water and diet (supplied as Hediste diversicolor), with another 14 days of depuration phase, it was concluded that the 14 days of exposure were not enough for the fish to reach a steady state on cadmium internal concentration, and neither the 14 days of elimination were sufficient to cause total depuration of the accumulated cadmium in any of the organs. Moreover, a higher concentration of cadmium was found in the intestine of the fish when compared with the rest of the organs, and the elimination rate constant of cadmium in the liver was nule. The Target Hazard Quotient (THQ) and the Estimated Weekly Intake (EWI) values for cadmium for the edible fraction of S. senegalensis were below the acceptable levels set by the European Regulation while for the shrimps both THQ and EWI exceeded the acceptable levels established
O cádmio é considerado um dos metais mais tóxicos para organismos aquáticos, podendo ocorrer naturalmente no ambiente em concentrações muito baixas, devido a processos naturais (e.g., erupções vulcânicas, erosão da crosta natural) mas também devido a atividades antropogénicas, como a atividade mineira. Como um subproduto da exploração mineira de zinco, o cádmio pode ser libertado para o ambiente aquático através de lixiviação ou escorrências. O cádmio é um metal não essencial para os organismos mas, mesmo em concentrações relativamente baixas, pode ser tóxico, provocando efeitos adversos devido à sua elevada tendência para bioacumular. Neste contexto, o objetivo deste trabalho foi estudar a transferência de cádmio em diferentes modelos de níveis tróficos marinhos. O estudo foi dividido em quatro etapas: i) avaliar a eco- e genotoxicidade de cádmio em três espécies marinhas, representando diferentes níveis tróficos marinhos ii) determinar a bioconcentração de cádmio por Acartia tonsa sob diferentes condições ambientais, tais como pH, salinidade e temperatura, iii) a avaliação de toxicocinética de cádmio pelo camarão estuarino Palaemon varians sob três vias de exposição diferentes: água, alimentação e água + alimentação, e iv) avaliar os padrões de bioacumulação de cádmio no linguado Solea senegalensis como consumidor final, e os possíveis riscos e implicações do consumo da fração edível de camarões e peixe que pode ter para a saúde humana, após a exposição a cádmio. Foi observado que a toxicidade de cádmio é influenciada pela sua especiação. A maior sensibilidade ao cádmio foi observada em A. tonsa tendo como parâmetro mas sensível o Índice de Desenvolvimento Larvar (LDR). O cádmio induziu danos no ADN de todas as espécies utilizadas. A bioconcentração de cádmio por A. tonsa é fortemente afetada por diferentes condições ambientais devido a processos biológicos. P. varians foi exposto a cádmio através de diferentes vias de exposição: água ou alimento ou água e alimento. A exposição simultânea de P. varians a água e alimento contaminado com cádmio mostrou que a concentração interna de cádmio foi maior quando comparada com as outras duas vias de exposição. Finalmente, mesmo uma exposição através de água e alimento contaminado (fornecido como Hediste diversicolor) não foi suficiente para que o peixe S. senegalensis atingisse um plateau na concentração interna de cádmio, sendo os 14 dias de depuração insuficientes para que os organismos depurassem totalmente a concentração interna que havia sido acumulada. Adicionalmente, foi encontrada uma maior concentração de cádmio no intestino de S. senegalensis quando comparada com os outros órgãos, e a constante de eliminação de cádmio no fígado foi inexistente. Os valores do Coeficiente de Perigo Alvo (THQ) e o Consumo Semanal Estimado (EWI) para o cádmio estavam abaixo dos níveis aceitáveis estabelecidos em regulamentos europeus para a fração edível de S. senegalensis, enquanto que para P. varians tanto o THQ quanto o EWI excederam os níveis aceitáveis estabelecidos.
Regester, Kurt Joel. "Ecosystem significance of ambystomatid salamanders : energy flow, habitat subsidies, and trophic interactions associated with their complex life cycles /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1342728871&sid=9&Fmt=2&clientId=1509&RQT=309&VName=PQD.
Повний текст джерелаGuiguer, Karin R. R. A. "Determination of Colpoys Bay (Georgian Bay) benthic community trophic structure and energy flow using stable isotopes and secondary production." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0022/NQ51199.pdf.
Повний текст джерелаParreira, de Castro Diego Marcel. "Functional diversity and trophic relationships in benthic communities : a multi-scale spatial approach in neotropical savanna streams." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1092/document.
Повний текст джерелаChanges in land cover and use and the associated environmental degradation due to human activities have resulted in extreme alterations of tropical ecosystems, especially in headwater streams and their watersheds in the neotropical savanna. Human pressures related to agricultural expansion and urbanization have led to drastic reductions in native vegetation cover, affecting riparian zones and degrading aquatic ecosystem functioning. There is an urgent need to quantify and predict how aquatic communities respond to different intensities of land use to guide conservation and natural resource management efforts. This thesis aims to evaluate how spatial scales influence the relationship between habitat and benthic macroinvertebrate communities and how land use intensity affects the trophic relationships and biological traits of macroinvertebrates. In Chapter 1, we evaluated how the intensity of land use (represented by a gradient moving from native vegetation toward pasture and sugar cane plantations) influences the energy flow and trophic niches of macroinvertebrates. In Chapter 2, we investigated the spatial scales (e.g., catchment, local) that most influence the taxonomic and functional composition of macroinvertebrate assemblages. Finally, in Chapter 3, we examined the impacts of human pressures on the functional diversity of macroinvertebrate assemblages. we showed that the intensity of land use affects benthic macroinvertebrate assemblages, yielding more generalist feeding behaviors with greater overlap of trophic niches (Chapter 1). In addition, environmental variables at the local and catchment scales significantly explained the variations in the taxonomic and functional composition of Ephemeroptera, Plecoptera and Trichoptera assemblages, but land use variables best explained the differences in functional composition among sites (Chapter 2). Finally, we showed that less impacted sites (under reference conditions) had more specialized and more functional diverse macroinvertebrate assemblages compared to disturbed sites (Chapter 3). These results corroborate the idea that biodiversity should be evaluated at multiple spatial scales and that the functional elements of biological communities should be considered when aiming for conservation and the development of predictive tools. This study contributes to a better understanding of the structure and functioning of streams in the neotropical savanna by subsidizing the development of environmental assessment tools. Such approaches will contribute to the development of more appropriate management and conservation measures that will allow for evaluation of the impacts on biota of further degradation of the ecological conditions in tropical streams
Zhang, Lu [Verfasser], Tillmann [Akademischer Betreuer] Lueders, Tillmann [Gutachter] Lueders, and Ingrid [Gutachter] Kögel-Knabner. "Insights into trophic connectivities and carbon flow through bacterial members of a belowground food web / Lu Zhang ; Gutachter: Tillmann Lueders, Ingrid Kögel-Knabner ; Betreuer: Tillmann Lueders." München : Universitätsbibliothek der TU München, 2018. http://d-nb.info/1163728713/34.
Повний текст джерелаRuiz, Jarrin Diego J. [Verfasser], Matthias [Akademischer Betreuer] Wolff, and Hauke [Akademischer Betreuer] Reuter. "Energy flow and trophic structure of Galápagos shallow rocky reef systems along a gradient of productivity and artisanal fisheries / Diego J Ruiz Jarrin. Gutachter: Matthias Wolff ; Hauke Reuter. Betreuer: Matthias Wolff." Bremen : Staats- und Universitätsbibliothek Bremen, 2015. http://d-nb.info/1077061730/34.
Повний текст джерелаSpengler, Thomas. "Influence of the ambient flow upon Rossby wave propagation between the tropics and extra-tropics /." Zürich : ETH, 2008. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17932.
Повний текст джерелаHummel, Adelaide Pereira. "Field Development and Performance Evaluation of a Constructed Wetland System in the Tropics." FIU Digital Commons, 2013. http://digitalcommons.fiu.edu/etd/1218.
Повний текст джерелаDolaptchiev, Stamen. "An asymptotic, nonlinear model for anisotropic, large scale flows in the tropics /." Potsdam : Potsdam Institute für Climate Impact Research, 2005. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=014749296&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Повний текст джерелаMarczak, Laurie Beth. "Trophic flows across ecosystem boundaries : an examination of the strength and consequences of linkages between stream and forest food webs." Thesis, University of British Columbia, 2007. http://hdl.handle.net/2429/30946.
Повний текст джерелаForestry, Faculty of
Graduate
Andrade, Diaz Claudia Verfasser], Thomas [Akademischer Betreuer] [Gutachter] Brey, and Dieter [Gutachter] [Piepenburg. "Trophic structures and flows in marine benthic communities of the Magellan Region, Southern Chile / Claudia Andrade Diaz ; Gutachter: Thomas Brey, Dieter Piepenburg ; Betreuer: Thomas Brey." Bremen : Staats- und Universitätsbibliothek Bremen, 2016. http://d-nb.info/1114869244/34.
Повний текст джерелаHaßler, Sibylle Kathrin. "Saturated hydraulic conductivity in the humid tropics : sources of variability, implications for monitoring and effects on near-surface hydrological flow paths." Phd thesis, Universität Potsdam, 2013. http://opus.kobv.de/ubp/volltexte/2013/6686/.
Повний текст джерелаTropische Regionen sind einem andauernden Landnutzungswandel unterworfen. Einerseits wird tropischer Regenwald für Holz- und Flächengewinnung abgeholzt, andererseits fallen Flächen im Zuge der Urbanisierung brach. Diese werden zum Teil mit Nutzholz-Plantagen aufgeforstet, zum Teil entwickelt sich auf ihnen natürlicher Sekundärwald. Änderungen in der Landnutzung beeinflussen Bodeneigenschaften und dadurch implizit den Wasserkreislauf der Region. Eine dieser wichtigen landnutzungsabhängigen Bodeneigenschaften ist die gesättigte hydraulische Leitfähigkeit oder Permeabilität, die maßgeblich die Versickerungsrate im Boden bestimmt. Eine niedrige Permeabilität hemmt die (vertikale) Versickerung und kann dazu führen, dass laterale hydrologische Fließpfade wie z.B. Oberflächenabfluss aktiviert werden. Dadurch wird sowohl die Bodenerosion und Nährstoffverlagerung verstärkt als auch die Auffüllung des Grundwasserspeichers verringert. In welchem Maße jedoch die Änderung der Permeabilität während des Landnutzungswandels eine Änderung der hydrologischen Fließpfade nach sich zieht, ist noch unzureichend erforscht. Die Zielstellung der vorliegenden Dissertation war, mit Hilfe der Permeabilität als Indikatorvariable die Auswirkungen des Landnutzungswandels auf bodennahe hydrologische Fließpfade zu beurteilen. Dabei sollten die Quellen der Variabilität der Permeabilität anhand des Einflusses von Bodentyp und Landnutzung eingeschätzt, diese Variabilität in das Design einer Probenahmestrategie für die Permeabilität integriert und die Auswirkungen dieser Einflüsse auf die Aktivierung lateraler Fließpfade untersucht werden. Die Studien wurden in Panama durchgeführt, da dieses Land stark vom Landnutzungswandel betroffen ist, eine gute Forschungsinfrastruktur aufweist und sich durch die hohen Niederschläge des tropischen Klimas Änderungen im Wasserkreislauf besonders stark auswirken. Zwei Teilstudien zu den Quellen der Variabilität der Permeabilität lieferten Hinweise auf einen möglichen Einfluss des Bodentyps, der jedoch durch den lokal stärkeren Einfluss der Landnutzung überprägt wurde. Auf regionaler Skala wurde die Erholung der Permeabilität unter Sekundärwald nach einer vorhergehenden Weidenutzung belegt. Beide Studien deuteten auf einen maßgeblichen Einfluss der Landnutzung und der räumlichen Struktur der Permeabilität auf die untersuchten Prozesse hin. Für die effiziente Abschätzung zeitlicher Veränderungen der Permeabilität, wie sie im Zuge des Landnutzungswandels auftritt, ist die Einbeziehung dieser räumlichen Strukturen in das Design einer Probenahmestrategie für die Permeabilität von großer Bedeutung, wie in einem Vergleich vier verschiedener Designs gezeigt wurde. Der Zusammenhang zwischen der Permeabilität und der Entstehung von Oberflächenabfluss konnte nicht durch einfache Ansätze, wie dem Vergleich der Permeabilität mit Regenintensitäten oder der Betrachtung des Gebietsabflusses, erklärt werden. Vielmehr scheint ein komplexes Zusammenspiel aus meteorologischen, biologischen, bodenkundlichen und hydrologischen Faktoren zu wirken. So wurde die räumliche Struktur des Oberflächenabflusses im Untersuchungsgebiet vermutlich durch eine Kombination aus Landnutzungs- und Permeabilitäts-Einflüssen bedingt, zu deren Aufklärung weitere notwendige Messungen vorgeschlagen werden. Zusammengefasst konnte anhand der Permeabilität der Einfluss des Landnutzungswandels auf die hydrologischen Fließpfade gut aufgezeigt werden. Eine besondere Bedeutung kommt hierbei der Betrachtung der landnutzungsabhängigen räumlichen Struktur der Permeabilität zu. Für die Prozessaufklärung der Aktivierung lateraler Fließpfade müssen jedoch Messungen aus verschiedenen Disziplinen kombiniert werden.
Gardner, Christopher Brent. "Rock-Derived Micronutrient Transport across Landscape Units: Hydrologic Flow Path Analysis and Catchment-Scale Transport in the Tropics and Small Mountainous Rivers." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449157172.
Повний текст джерелаHaßler, Sibylle Kathrin [Verfasser], and Helmut [Akademischer Betreuer] Elsenbeer. "Saturated hydraulic conductivity in the humid tropics : sources of variability, implications for monitoring and effects on near-surface hydrological flow paths / Sibylle Kathrin Haßler. Betreuer: Helmut Elsenbeer." Potsdam : Universitätsbibliothek der Universität Potsdam, 2013. http://d-nb.info/1038344689/34.
Повний текст джерелаLuiz, Tatiane Ferraz. "Estrutura e ecologia trófica da Ictiofauna da microbacia do córrego Beija-Flor, Estação Ecológica de Jataí, Luiz Antônio, SP." Universidade Federal de São Carlos, 2014. https://repositorio.ufscar.br/handle/ufscar/1823.
Повний текст джерелаUniversidade Federal de Sao Carlos
The objective of this study was to analyze the structure, composition, trophic ecology and food items shared by the fish fauna in the stream Beija -Flor, located in Jataí Ecological Station ( 21 ⁰ 36'32 .8 " S 47 ⁰ 48'0 .54 " W ), besides characterizing the trophic ecology of the species Hemigrammus marginatus, one of the most abundant in the Beija-Flor stream. The samples of fish were collected monthly from August 2011 to July 2012, using gill nets, trawl nets and baited traps in five sampling stations distributed along the Beija-Flor stream. The fish were fixed in 10% formalin in the field and in the laboratory were identified and subjected to biometric measurements. The stomachs were weighed and transferred to 70% alcohol and stomach contents were examined under a stereomicroscope to the lowest possible taxonomic level. Forty four fish species belonging to 33 genera, 16 families and 5 orders were collected. Most species were accidental ( 43.18 % ), followed by constant species ( 38.64 % ) and accessory (18.18 % ). The diet of 30 species was analyzed. The main dietary habit was insectivorous, followed by omnivorous habits, herbivorous, piscivorous and detritivore. The dietary overlap was high in several species during periods of dry and flood. Hemigrammus marginatus was classified as an insectivore. Food items of autochthonous origin of the orders Ephemeroptera and Trichoptera were more important during the dry season, while the items of allochthonous origin of the order Hymenoptera, were more important in the rainy season. The increase in the quantity and variety of food items during the flooding causes some species of fish to become more generalist and share food resources. Hemigrammus marginatus, Astyanax altiparanae, Metynnis maculatus, Serrapinnus notomelas and Oligosarcus pintoi, have complex of interactions with the food items and can be considered key species for stream Beija- Flor. The results showed that the stream Beija-Flor is a preserved, with high species diversity by being located within the Jataí Ecological Station, but is highly threatened by being surrounded by sugar cane plantations.
O Córrego Beija-Flor, localizado na Estação Ecológica de Jataí (21⁰36 32.8 S 47⁰48 0.54 W), é formado pelos córregos da Bandeira, do Jordão e das Cabaças, e deságua no rio Mogi-Guaçu, bacia do alto Paraná. O objetivo deste trabalho foi analisar a estrutura, a composição, a ecologia trófica, e o compartilhamento de itens alimentares pela ictiofauna e caracterizar a ecologia trófica da espécie Hemigrammus marginatus, uma das espécies mais abundantes do córrego Beija-Flor. As coletas de peixes foram realizadas mensalmente no período de agosto de 2011 a julho de 2012, utilizando-se redes de espera, rede de arrasto e armadilhas iscadas do tipo covo, em cinco estações de coleta distribuídas ao longo do córrego Beija-Flor. Os peixes foram fixados em formol 10% no campo e em laboratório foram identificados e submetidos a medidas biométricas. Os estômagos foram pesados e transferidos para álcool 70% e o conteúdo estomacal foi analisado em estereomicroscópio até o menor nível taxonômico possível. Foram coletadas 44 espécies de peixes pertencentes a 33 gêneros, 16 famílias e 5 ordens. A maioria das espécies foi de ocorrência acidental (43,18 %), seguida pelas espécies constantes (38,64 %) e acessórias (18,18 %). A dieta de 30 espécies foi analisada. O principal hábito alimentar foi insetívoro, seguido pelos hábitos onívoro, herbívoro, piscívoro e detritívoro. A sobreposição alimentar foi alta em diversas espécies nos períodos de seca e cheia. Hemigrammus marginatus foi considerado insetívoro. Os itens alimentares de origem autóctone das ordens Ephemeroptera e Trichoptera foram mais importantes no período de seca, enquanto os itens de origem alóctone, da ordem Hymenoptera, tiveram maior importância no período de cheia. O aumento na quantidade e variedade de itens alimentares no período de cheia faz com que algumas espécies de peixes se tornem mais generalistas e partilhem os recursos alimentares. Hemigrammus marginatus, Astyanax altiparanae, Metynnis maculatus, Serrapinnus notomelas e Oligosarcus pintoi, possuem um complexo de interações com os itens alimentares e podem ser consideradas espécies chaves para o córrego Beija- Flor. Os resultados mostraram que o córrego Beija-Flor é um riacho preservado, com alta diversidade de espécies por estar localizado dentro da Estação Ecológica de Jataí, mas encontra-se fortemente ameaçado por estar cercado por plantações de cana de açúcar.
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