The plankton community of the Gulf of California exist in a transition region from oceanic to neritic habitats, tropical to warm-temperature waters that is strongly influenced by a complex hydrography and bathymetry. Hyperiid Amphipods were chosen as a focus of this study to elucidate the various forces that shape the distributions of the entire community. To test how strongly hyperiids select water of a particular type (the "Water Mass" hypothesis), multiple regression analysis was applied to species' distributions and station hydrography. The quantitative results indicate that there is a strong relation between the distribution of a given hyperiid and the location of discrete water bodies in the Gulf of California. Three linked gyral currents, powered by a tidally-driven interval wave have been hypothesized to influence phytoplankton distributions in the Gulf. Through both qualitative and quantitative statistical analysis, these gyres are shown to be quite important in structuring species' distributions and have a strong effect on the character of the Gulf hydrography. Significant change in community diversity are found to occur only at the boundaries of these gyres. Many authors consider hyperiid amphipods as obligate parasites upon gelatinous zooplankton, and not worthy of distributional analyses. Both qualitative and quantitative test of this hypothesized relationship between hyperiid and "host" offer little support for the concept of hyperiid amphipods as parasites. Instead, there is considerable evidence that hyperiids are "substrate-bound," as are most amphipods, and use gelatinous zooplankton as facultative, transient hosts. Being able to switch hosts as desired, hyperiids can select for optimum conditions, and can serve to model the zooplankton community as a whole.

Les contaminations multiples par des métaux et métalloïdes menacent la structure et le fonctionnement des écosystèmes aquatiques. Pourtant, les mécanismes d'action des polluants, leurs interactions et leur toxicité dans un contexte de réchauffement climatique sont encore peu abordés. Parallèlement, nous avons un besoin urgent de marqueurs d'alerte (i.e., précoces, sub-létaux) des effets de ces substances. Par ailleurs, une attention croissante est actuellement portée au protéome des êtres vivants, considéré comme une entité dynamique, modifié par les conditions du milieu. Dans ce contexte, nous avons travaillé en laboratoire avec comme espèce modèle le crustacé amphipode Gammarus pulex avec trois objectifs: (1) évaluer les effets de deux éléments métalliques (cadmium et arséniate) seuls ou en interaction sur des organismes exposés en conditions contrôlées, (2) appréhender les effets de la température en tant que facteur confondant potentiel des réponses mesurées, et (3) rechercher l'existence d'une réponse singulière potentielle du protéome d'individus exposés aux éléments métalliques seuls ou en mélange ; à plusieurs températures. Il s'agissait donc à la fois de réaliser une analyse diagnostique susceptible de fournir des marqueurs d'intérêt aptes à révéler précocement un stress chimique et de dresser les bases d'une approche pronostique permettant de mieux prédire les conséquences à l'échelle individuelle d'une dégradation anthropique du milieu / Multiple metal and metalloid contaminations impair aquatic ecosystem community structure and functioning. However, the mechanistic understanding of individual pollutant toxic effects, but also of their interaction effects in a "global warning" context are still rarely tackled. However, aquatic ecosystem managers have an urgent need of early warning indicators (i.e. early, sub-lethal) of toxicant effects. Recently, an increasing attention has been turned to studies of the proteome of species/populations, which is considered as a dynamic entity modified by environmental conditions. In this context, we have worked with a model organism, Gammarus pulex (crustacea, amphipoda), under laboratory controlled conditions. Three objectives have been defined: (1) assessing the single and combined effects of two metals (i.e. arsenate and/or cadmium), (2) understanding the potential confounding effect of temperature on measured physiological and behavioural responses of gammarids and (3) investigating the existence of a singular response of the proteome of individuals exposed to different single or combined metal concentrations, at several tested temperatures. The major goals were first applying a diagnostic analysis to provide valuable biomarkers early indicating metallic stress, and second developing the foundations for a prognostic approach better predicting the organismal consequences of toxic contaminations due to the anthropogenic degradation of aquatic ecosystems

Hyale media (Dana, 1853), Gammaridea do fital da Praia do Poço (Poço de Anchieta), Itanhaem, litoral sul do Estado de são Paulo, foi estudada durante o inverno e verão do ano de 1979. A espécie foi analisada quanto ã sua distribuição e abundância em um dos costões rochosos do local, quanto a sua alimentaçao e como animal presa para peixes da região do fital. A abundância da espécie, em relação aos demais Gammaridea, foi obtida através do índice de Densidade Relativa e a distribuição vertical e horizontal, pela sua ocorrencia nas algas do costão rochoso. A importância da espécie como presa de peixes do fital foi avaliada através da análise do conteúdo estomacal de algumas espécies, notadamente Blennius cristatus. Aspectos quantitativos e qualitativos da alimentação de Hyale media foram analisados experimentalmente em 4 estádios de desenvolvimento da espécie, utilizando-se alimentos vegetal e animal. Os resultados obtidos revelaram que Hyale media é uma espécie de distribuiçao ampla no costão rochoso, ocorrendo em maior abundância nas algas dos níveis mais baixos. Hyale media é uma espécie omnívora, que se utiliza de vários mecanismos para aquisição de alimentos, à exceção da filtração. No inverno, a preferência da especie recaiu sobre o alimento Sargasswn stenophyllwn e, no verão, sobre o alimento Ulva fasciata, não ocorrendo, porem, diferença significativa entre o inverno e o verão, quanto à utilização de Alimento Animal. O estádio mais desenvolvido de Hyale media (macho 2) teve altas porcentagens de assimilação, embora apresentasse baixas razões de ingestão, assimilação e eliminação, tanto no inverno quanto verão. Este comportamento não foi observado nos demais estádios. Maiores porcentagens de assimilação foram, em geral, obtidas no verao. Hyale media serve de alimento para os peixes da região algal estudada e parece ser um importante membro na cadeia trófica da região. / The Gammaridea Hyale media (Dana, 1853) living in the phytal of Praia do Poço, Itanhaém, southern coast of São Paulo State, was studied during the winter and summer of 1979. The study included the local distribution and abundance of the species. Qualitative and quantitative analyses on the feeding of Hyale media, at laboratory conditions, were also made. The results showed that the species lives more frequently on algae occurring at inferior levels of the rock. Hyale media is a food item of great value for intertidal fish, specially for Blennius cristatus. Therefore, it would probably be an important element of the local food chain. The species is omnivorous and its feeding mechanisms are browsing, predation, scavenging and scraping. Filter-feeding was not observed in Hyale media. Concerning its preference for different types of food, the studied Gammaridea preferred Sargassum stenophyllum in the winter and Ulva fasciata in the summer. In relation to Animal food there was no significative difference between winter and summer. Male 2 (more advanced stage) presented high percentage of food assimilation al though ingestion, assimilation and elimination rates were low, during the two seasons. The same was not true for the early stages. However, in general, Hyale media reached higher percentage of assimilation in the summer.

No description available.

4-nonylphenol (NP), a surfactant degradation product, is an unregulated, ubiquitous aquatic contaminant and endocrine disruptor, for which aquatic life criteria are currently under development by U.S. EPA. The effects of NP on estuarine amphipods and chinook salmon fry were investigated, and this dissertation reports research into the impacts of NP bioaccumulation on the amphipods and resultant endocrine disruption of their juvenile salmon predators. Sensitivity to, and bioaccumulation of, NP by benthic amphipods were quantified. Factors affecting the bioavailability of NP to three species of amphipod (Eohaustorius estuarius, Grandidierella japonica, and Corophium salmonis) were determined in contaminated sediments. Standard bioassay techniques were modified to determine toxicity and bioaccumulation, with varying amounts and differing nutritional qualities of sedimentary organic carbon. �����C-Ring-labeled NP was used as a tracer in the experiments to quantify amphipod exposures. NP was acutely toxic to Eohaustorius estuarius from aqueous exposures, mean (+/-SD) LC50=227 ��g/L +/- 56, 1 h mean reburial EC50=138 +/- 36. The predicted LC50 for NP (202 ��g/L) from an amphipod-derived structure-activity relationship was not significantly different (p>0.05) from our empirically derived LC50 (227 ��g/L). All three amphipod species accumulated significant NP body burdens. Accumulation was inversely proportional to the total amount of organic carbon, but it did not differ between types of organic matter. Calculated accumulation factors indicated that amphipods could be an important and previously unrecognized source of NP to higher trophic levels. Plasma vitellogenin (Vtg) was quantified in juvenile chinook salmon following dietary exposure to NP contaminated amphipods and aqueous exposure to multiple NP concentrations. Fry that had fed upon contaminated amphipods did not have significantly greater Vtg levels than controls; however, Vtg was detected in 30 percent of fry. NP aqueous concentrations at 60 and 240 ��g/L significantly induced Vtg in fry following 5 d exposures. The 240 ��g/L aquatic NP treatment fry had comparable levels of Vtg to the positive control treatment in which fry were injected 17B-estradiol. These results indicate that amphipods are potential vectors of sediment NP to higher trophic levels within the water column, including juvenile chinook salmon. / Graduation date: 2003

Il lavoro qui presentato è incentrato sulla caratterizzazione dei Fontanili - risorgive semi-natural1 comuni della regione Lombardia (Nord Italia), GDES rilevanti per il progetto GENESIS sulle acque sotterranee (progetto europeo finanziato nell'ambito del 7th Framework Programme). Gli obiettivi di questo lavoro di dottorato sono stati: - Caratterizzare gli ecosistemi Fontanili sulla base delle conoscenze scientifiche disponibili; - Individuare le risposte ecotossicologiche di un indigeno specie bentoniche macroinvertebrati alla contaminazione agricola attraverso la sperimentazione in Fontanili per verificare se il metodo applicato può servire come bioindicatore della contaminazione negli ecosistemi Fontanili. Gli obiettivi indicati sono affrontati nelle sezioni seguenti. Sezione 3 caratterizza gli ecosistemi Fontanili sulla base delle conoscenze scientifiche disponibili. La sezione 4 è una rivista di indicatori biologici per la valutazione della qualità delle acque con particolare attenzione alla macroinvertebrati. La sezione 5 presenta i risultati degli studi su Fontanili selezionati con l'uso di un test biologico in situ di alimentazione con un anfipode indigena Echinogammarus stammeri. I capitoli 6 e 7 sono esperimenti di laboratorio condotti per misurare le risposte delle anfipodi di inquinanti agricoli rilevati nei Fontanili studiati. A parte il lavoro condotto in Italia, l'autore insieme a Sarah Joseffson dal Dipartimento di Scienze acquatica e Valutazione, Università Svedese di Scienze Agrarie a Uppsala, in Svezia eseguito uno studio "Trasferimento di inquinanti organici persistenti da acquatico a ambienti terrestri con insetti acquatici come vettori" nel 2012. La descrizione e preliminari risultati di questo lavoro di studio possono essere trovati nell'appendice I. / The work presented here is focused on characterization of fontanili - semi-natural1 springs common in the Lombardy region (North Italy), relevant groundwater dependent ecosystems for the GENESIS project on groudwater systems (European project funded under the 7th Framework Programme). The objectives of this PhD work were: - to characterize the fontanili ecosystems based on the available scientific knowledge; - to identify ecotoxicological responses of an indigenous macroinvertebrate benthic species to agricultural contamination through experimentation in fontanili ecosystems This will test if the applied method can serve as a bioindicator of contamination in the fontanili ecosystems. The mentioned objectives are addressed in the following sections. Section 3 characterizes the fontanili ecosystems based on the available scientific knowledge. Section 4 is an overview of biological indicators as water quality assessment with focus on macroinvertebrates. Section 5 presents the results of field studies on selected fontanili sites with the use of an in situ feeding bioassay with an indigenous amphipod Echinogammarus stammeri. Chapters 6 and 7 are laboratory experiments conducted to measure the responses of the amphipods to commonly detected agricultural pollutants in the studied fontanili. Apart from the work conducted in Italy, the author together with Sarah Joseffson from the Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences in Uppsala, Sweden performed a study “Transfer of persistent organic pollutants from aquatic to terrestrial environments with aquatic insects as vectors” in 2012. The description and preliminary results of this study work can be found in Appendix I.

Ecosystems are linked by spatial subsidies, the bi-directional flows of nutrients, materials and energy that cross ecosystem boundaries. Considered one of the planet’s most productive and diverse meta-ecosystems, the broad interface between land and sea is crossed by innumerable abiotic and biotic spatial subsidies, including migratory animals. Routinely crossing ecological boundaries, migrants play significant roles in subsidizing receiving ecosystems, including influencing ecosystem productivity, diversity, community structure and trophic cascades. On the Pacific coast of North America, spatial subsidies driven by migratory Pacific salmon have been intensively studied. Like many of the world’s migrants, however, salmon populations have declined considerably and most of our scientific knowledge has been gained from a diminished subsidy. Other subsidies, including those driven by migratory species in decline, remain relatively unknown. Each year, Pacific herring (Clupea pallasii) migrate to shallow waters to spawn on nearshore and intertidal substrates. Despite suggestions in the literature that herring, an abundant, nearshore/intertidal spawning forage fish, subsidizes coastal ecosystems, there had been no investigation of cross-ecosystem interactions. Just as stable isotopes and fatty acids have been used to explore wrack (drift macrophytes) subsidies to intertidal ecosystems, we combined both approaches to trace the input of Pacific herring and wrack to semi-terrestrial amphipods (Traskorchestia spp.), which are highly abundant detritivores in beach ecosystems. Brown algae and seagrass were major contributors to amphipods but when available, herring was also a significant resource. Because amphipods are prey for terrestrial consumers, including bears (Ursus spp.), we also identified indirect trophic linkages between herring and terrestrial ecosystems. Bears are major consumers and vectors of salmon into terrestrial ecosystems, but little is known regarding their involvement in other spatial subsidies. Using a model-based inference approach paired with remote cameras to monitor intertidal black bear (U. americanus) activity, we determined that the best predictors of black bear intertidal activity were major intertidal prey items (herring and amphipod biomass) and Julian day. Bears positively responded to herring and amphipod biomass on beaches but it was the analysis of scats that determined the contribution of herring eggs to the diets of bears. In 2010, the herring spawn was relatively poor and consumption of eggs was negligible, with amphipods constituting a major portion of bear diets. In following years, herring egg loading was relatively high and eggs were the dominant dietary item in bear scats. Tracing the contribution of herring into terrestrial areas proved challenging and instead, we furthered knowledge of the within-watershed spatiotemporal influences of salmon on conifer tree ring growth and δ15N signatures. Both tree ring growth and δ15N signatures tracked the known spatial distribution of salmon carcasses. Using a model-based inference approach, salmon abundance and interaction terms of salmon*temperature and salmon*distance into the forest best predicted tree growth. In contrast, salmon abundance was not a leading predictor of δ15N. By broadening our understanding of the fine-scale influence of salmon on a stand of ancient trees, this research is expected to contribute to future exploration of the terrestrial influences of Pacific herring. / Graduate / 0329 / cfox@uvic.ca

Hyale media (Dana, 1853), Gammaridea do fital da Praia do Poço (Poço de Anchieta), Itanhaem, litoral sul do Estado de são Paulo, foi estudada durante o inverno e verão do ano de 1979. A espécie foi analisada quanto ã sua distribuição e abundância em um dos costões rochosos do local, quanto a sua alimentaçao e como animal presa para peixes da região do fital. A abundância da espécie, em relação aos demais Gammaridea, foi obtida através do índice de Densidade Relativa e a distribuição vertical e horizontal, pela sua ocorrencia nas algas do costão rochoso. A importância da espécie como presa de peixes do fital foi avaliada através da análise do conteúdo estomacal de algumas espécies, notadamente Blennius cristatus. Aspectos quantitativos e qualitativos da alimentação de Hyale media foram analisados experimentalmente em 4 estádios de desenvolvimento da espécie, utilizando-se alimentos vegetal e animal. Os resultados obtidos revelaram que Hyale media é uma espécie de distribuiçao ampla no costão rochoso, ocorrendo em maior abundância nas algas dos níveis mais baixos. Hyale media é uma espécie omnívora, que se utiliza de vários mecanismos para aquisição de alimentos, à exceção da filtração. No inverno, a preferência da especie recaiu sobre o alimento Sargasswn stenophyllwn e, no verão, sobre o alimento Ulva fasciata, não ocorrendo, porem, diferença significativa entre o inverno e o verão, quanto à utilização de Alimento Animal. O estádio mais desenvolvido de Hyale media (macho 2) teve altas porcentagens de assimilação, embora apresentasse baixas razões de ingestão, assimilação e eliminação, tanto no inverno quanto verão. Este comportamento não foi observado nos demais estádios. Maiores porcentagens de assimilação foram, em geral, obtidas no verao. Hyale media serve de alimento para os peixes da região algal estudada e parece ser um importante membro na cadeia trófica da região. / The Gammaridea Hyale media (Dana, 1853) living in the phytal of Praia do Poço, Itanhaém, southern coast of São Paulo State, was studied during the winter and summer of 1979. The study included the local distribution and abundance of the species. Qualitative and quantitative analyses on the feeding of Hyale media, at laboratory conditions, were also made. The results showed that the species lives more frequently on algae occurring at inferior levels of the rock. Hyale media is a food item of great value for intertidal fish, specially for Blennius cristatus. Therefore, it would probably be an important element of the local food chain. The species is omnivorous and its feeding mechanisms are browsing, predation, scavenging and scraping. Filter-feeding was not observed in Hyale media. Concerning its preference for different types of food, the studied Gammaridea preferred Sargassum stenophyllum in the winter and Ulva fasciata in the summer. In relation to Animal food there was no significative difference between winter and summer. Male 2 (more advanced stage) presented high percentage of food assimilation al though ingestion, assimilation and elimination rates were low, during the two seasons. The same was not true for the early stages. However, in general, Hyale media reached higher percentage of assimilation in the summer.

Orientadores: Fosca Pedini Pereira Leite, Giuliano Buzá Jacobucci / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T12:16:02Z (GMT). No. of bitstreams: 1 Siqueira_SilvanaGomesLeite_D.pdf: 2460624 bytes, checksum: 11cc560773d9117ec50e5c04d3f4ba0c (MD5) Previous issue date: 2012 / Resumo: O monitoramento dos ambientes marinhos pode ser feito avaliando a presença de poluentes em organismos que são capazes de acumular estas substâncias. Desta forma, este estudo avaliou a presença de hidrocarbonetos petrogênicos na alga parda Sargassum furcatum e em anfípodes ampitoídeos associados provenientes de costões rochosos do Canal de São Sebastião, o qual está sujeito à poluição por petróleo, devido às operações do Duto e Terminais Centro Sul (DTCS) e por efluentes domésticos. Identificou-se as espécies de ampitoídeos que ocorreram associadas ao S. furcatum estudando também a variação espacial e temporal da composição desta comunidade. A relação entre os hidrocarbonetos presentes em S. furcatum, a densidade e a estrutura populacional de Cymadusa filosa, espécie de ampitoídeo mais representativa da região, também foi investigada. Adicionalmente foi realizado o estudo do comportamento reprodutivo de C. filosa e avaliado o seu uso como bioindicador de qualidade da água, por meio de teste de toxidade aguda de curta duração. O material analisado foi proveniente de 7 coletas realizadas entre março de 2007 a novembro de 2008 em 7 costões rochosos. Foram quantificados os hidrocarbonetos alifáticos e policíclicos aromáticos derivados de petróleo tanto na alga como nos anfípodes, que compostos variaram em termos de concentração entre os meses amostrados. A alga possivelmente refletiu as concentrações de hidrocarbonetos presentes na água enquanto que os anfípodes podem ter assimilado via contato direto ou via alimentação. Foram identificadas seis espécies de anfípodes da Família Ampithoidae: Ampithoe sp., A. divisura, A. marcuzzi, A. ramondi, C. filosa e Sunampithoe pelagica que apresentaram diferenças significativas em termos de ocorrência, densidades e variação temporal. A população de C. filosa, de modo geral, foi dominada por jovens, possivelmente devido a elevada fecundidade das fêmeas. Ocorreu também desvio da razão sexual a favor das fêmeas, relacionado com o comportamento diferencial do macho ou devido a sua maior sensibilidade aos hidrocarbonetos presentes na alga. Tanto hidrocarbonetos alifáticos como policíclicos aromáticos influenciaram a densidade e estrutura de tamanho dos diferentes estádios de desenvolvimento de C. filosa. Foram observadas interações agonísticas entre machos e fêmeas de C.filosa, formação de tubos conjugais e a alimentação de filhotes ainda no marsúpio pela fêmea, caracterizando o cuidado parental desta espécie. Verificou-se ainda que o período de incubação dos ovos foi curto e a maturidade sexual ocorreu entre seis a sete semanas. Os resultados de toxidade aguda sugerem que C.filosa tem um potencial para uso em experimentos de ecotoxicologia marinha devido a elevada sensibilidade ao cobre e ao naftaleno, contudo estudos adicionais com outros xenobióticos são necessários para comprovação destes resultados e para validar o uso desta espécie no monitoramento dos ambientes marinhos / Abstract: The monitoring of marine environments can be made by evaluation of pollutant presence in organisms that are able to accumulate these substances. Thus, this study evaluated the occurrence of oil-derived hydrocarbons in the brown algae Sargassum furcatum and in its associated amphitoid amphipods found on rocky shores of the São Sebastião Channel, which is exposed to pollution by oil due to the operations of the Duct and Center Southern Terminal (DTCS) and domestic sewage. The species of amphitoid that occurred associated to S. furcatum were identified, and time and spatial variation of the composition of this community were also studied. The relationship between the hydrocarbons present in S. furcatum and the density and populational stucture of Cymadusa filosa, the most representative species of amphitoid in the area, was also investigated. Additionally a study on the reproductive behavior of C. filosa was conducted and its use as a bioindicator of water quality was evaluated through high toxicity test of short duration. The analysed material was obtained from 7 samples taken from march 2007 to november 2008 on 7 rocky shores. The oil-derived aliphatic and polycyclic aromatic hydrocarbons were quantified both in the algae and in the amphipods. Such compounds varied in concentration between the months of sampling. The algae possibly reflected the hydrocarbon concentrations present in the water while the amphipods may have assimilated hydrocarbons by direct contact or through the trophic chain. Six species of amphipods from the Ampithoidae family were identified: Ampithoe sp., A. divisura, A. marcuzzi, A. ramondi, C. filosa and Sunampithoe pelagica which presented significant differences in occurrence, density and temporal variation. The population of C. filosa in general was dominated by young individuals, possibly due to the high fecundity of the females, and there was a deviation of the sexual ratio favoring the females, related to the male?s differential behavior or due to its higher sensibility to hydrocarbons in the algae. Both aliphatic and polycyclic aromatic hydrocarbons influenced the density and size structure of the different stages of development of C. filosa. Agonistic interactions between male and female C. filosa were observed, formation of share tubes and feeding of the offspring still in the pouch by the female, characterizing parental care by this species. It was also verified that the egg incubation period was short and sexual maturity occurred between six and seven weeks. The results of high toxicity suggest that C. filosa has potential for use in experiments of marine ecotoxicology due to its high sensibility to copper and naphthalene, however, additional studies with other xenonbiotics are necessary to confirm these results and to validate the use of this species in marine environments monitoring / Doutorado / Ecologia / Doutora em Ecologia

Made available in DSpace on 2014-06-12T23:02:45Z (GMT). No. of bitstreams: 2 arquivo8264_1.pdf: 5239097 bytes, checksum: 9d0fd88cd3faeb69e380c5bf3013bfa0 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2007 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / No mundo, a taxonomia e a ecologia dos Amphipoda de região tropical são pouco estudadas se comparada com as regiões temperadas e de altas latitudes. Por isso o presente trabalho teve por objetivo estudar a comunidade de Amphipoda da Plataforma Continental e Bancos Oceânicos da Região Nordeste do Brasil, coletados durante o Programa REVIZEE-NE. Foi analisado um total de 3.103 indivíduos coletados através de dragagens em 30 estações, durante Maio e Junho de 1998 e Novembro e Dezembro de 2000, pelo N. Oc. Antares . Foram obtidos para cada estação os dados abióticos de temperatura, profundidade, salinidade e dados de sedimento. Os organismos após triados, foram fixados em álcool a 70%, e identificação sob estereomicroscópio e microscópio, com o auxílio das referências bibliográficas especializadas. A comunidade foi caracterizada através dos seguintes descritores biológicos: abundância total, diversidade específica, eqüitabilidade, freqüência de ocorrência e riqueza de Margalef. Foi utilizado o teste U , Mann-Whitney, em nível de significância de 95% (α = 0,05) para se verificar as diferenças entre esses descritores. Para a análise dos dados abióticos e bióticos foram utilizadas as análises multivariadas de Agrupamento, dos Componentes Principais (ACP) e Escalonamento multidimensional (MDS). Como esperado para as características oceanográficas da Região Nordeste, a temperatura e salinidade mantiveram-se quase constantes, com médias acima de 27ºC e 36 UPS, respectivamente. A profundidade variou de 22 a 74 m de profundidade. Foram identificadas 73 espécies, sendo 61 novas ocorrências para os bancos oceânicos da Cadeia Norte e Fernando de Noronha e 14 novas ocorrências para o Atlântico Sul Ocidental. Leucothoe tridens, Gammaropsis (Gammaropsis) atlantica, Leucothoe urospinosa e Elasmopus sp. foram as espécies mais freqüentes. Na Cadeia de Fernando de Noronha foi registrada diversidade, abundância e média de riqueza em comparação com a plataforma continental e Cadeia Norte. Todas as estações apresentaram valores de eqüitabilidade superiores a 0,5, sendo a feição arenosa mais eqüitativa que a cascalhosa (α = 0,028). A ACP evidenciou primeiramente as interações biológicas e, secundariamente, o tipo de sedimento como os principais fatores reguladores da comunidade de Amphipoda da Região Nordeste do Brasil. A análise de agrupamento e o MDS demonstraram a importância do tipo de sedimento, principalmente, a granulometria, na caracterização das subáreas estudadas