922 resultados para Estuarine ecosystems


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The zooplankton communities of two lacustrine ecosystems in southwestern Amazonia (Lago Amapá and Lago Pirapora) were studied based on samples collected over an 11-month period. The general aim of the present work was to contribute to the knowledge of the zooplankton fauna in southwestern Amazonia, by studying the occurrence of certain species; and to improve the knowledge of the Rio Acre tributaries. The total number of taxa included 38 species of rotifers, 6 cladocerans and 7 copepods. Most of the species were from the rotifer family Brachionidae. Jaccard's similarity index was similar for the two lakes at 0.6964 The constancy index defined the species Keratella cochlearis, Filinia cf. terminate, Filinia opoliensis, Hexarthra intermedia braziliensis, Ceriodaphnia cornuta, Moina minuta, Diaphanosoma spinulosnm, and immature forms (nauplii and copepodites) as the constant in these lakes. The presence of zooplankton with higher number of species occupying the middle depths, during morning and night periods.

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The objective of the present study was to characterize the spatial distribution and shell utilization of three hermit crab species in the estuarine-bay complex of São Vicente, São Paulo State, Brazil. Monthly samples were done throughout two years, in the non-consolidated sub-littoral at the estuarine-bay complex. The environmental factors, such as temperature, salinity and depth, were measured every month. The three hermit crab species, Clibanarius vittatus, Loxopagurus loxochelis and Isocheles sawayai, were captured utilizing shells from six gastropods species; 92.7% of the hermit crabs utilized Stramonita haemastoma. The results suggest a strong correlation between hermit crabs spatial distribution and salinity, which was considered the main environmental factor limiting their distribution in the estuary. I. sawayai was the only species present in all transects sampled; C. vittatus was captured only in regions with low salinity and L. loxochelis occurred only in high salinity waters.

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Diseases transmitted by water consists a serious public health problem and enterobacteria are the main group of microorganisms responsible for outbreaks in humans. Such pathogenic bacteria proliferate in water polluted by domestic and industrial sewage and reach the population through seawater contact. The aim of the present work was to study environmental parameters as well as to identify Enterobacteriaceae species and their antimicrobial susceptibility in water samples collected from the estuarine area of São Vicente city (São Paulo State, Brazil). Strains were identified by using traditional biochemical tests described in literature and antimicrobial susceptibility tests were carried out using the disk diffusion method. Out of 26 samples, Escherichia coli was the most frequent species (40.1%), followed by Citrobacter, Enterobacter and Klebsiella. The most effective drugs against the tested microorganisms were gentamycin, netilmicin, ciprofloxacin and cefepime. Since these bacteria are commonly found in seashore contaminated by sewage effluents, it can be concluded that estuarine waters of São Vicente are polluted and potentially capable of causing diseases and spreading pathogenic bacteria to human communities.

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Forecast of biological consequences of climate changes depend on both long-term observations and the establishment of carbon budgets within pelagic ecosystems, including the assessment of biomasses and activities of all players in the global carbon cycle. Approximately 25% of oceanic primary happen over continental shelves, so these are important sites for studies of global carbon dynamics. The Brazilian Continental Shelf (BCS) has sparse and non-systematic in situ information on phytoplankton biomass, making products derived from ocean color remote sensing extremely valuable. This work analyzes chlorophyll concentration (Chl) estimated from four ocean color sensors (CZCS, OCTS, SeaWiFS and MODIS) over the BCS, to compare Chl and annual cycles meridionally. Also, useful complementary ocean color variables are presented. Chl gradients increased from the central region towards north and south, limited by estuarine plumes of Amazon and La Plata rivers, and clear annual Chl cycles appear in most areas. In southern and central areas, annual cycles show strong seasonal variability while interannual and long-term variability are equally important in the remaining areas. This is the first comparative evaluation of the Chl over the BCS and will aid the understanding of its long-term variability; essential initial step for discussions of climate changes.

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Sediments from Guaratuba Bay (PR, Brazil), a marine protected area, were collected and evaluated for geochemistry and toxicity. High levels of P and acute toxicity were observed in some samples. Concentrations of Cu, Cd, Pb and Zn were relatively low; however, Cd levels eventually exceeded Threshold Effect Level. Toxicities were associated to nutrients and metals enrichment. Results suggest that impacts are incipient and occur only at specific sites, associated to multiple contamination sources. Despite sediments quality seems to range between good and fair, attention is required to land-use planning around Guaratuba Bay and controlling local pollution sources. © 2013 Elsevier Ltd. All rights reserved.

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The present study reports the use of biomarkers analyzes in mangrove root crab Goniopsis cruentata tissues to assess the environmental quality of two tropical estuarine areas. Animals from Ceará River estuary presented inhibition of ChE and GST enzymatic activities and higher rates of DNA damage with respect to those sampled in a pristine environment. G. cruentata appears to represent a proper species to monitor the quality of tropical estuaries. Since Ceará River is a legally protected area, this survey highlight the needs to implement actions to control pollution loads and improve the protection of natural ecosystems and resources. © 2013 Elsevier Ltd. All rights reserved.

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The objective of this study was to address the importance of implementing Coastal and Marine Protected Areas in Brazil and to examine their distribution, based on the delimitation of Large Marine Ecosystems. Out of a total of 336 protected areas identified in Brazilian coastal and marine areas, the North Platform has the largest protected area, but the ecosystem with the largest number of protected area, predominantly sustainable areas, was the East Coast followed by the South Platform. One of the reasons the eastern coast of Brazil to have more protected areas is the fact that there is a largest amount of coral reefs. Additionally there was political opportunities for the creation of protected areas for sustainable use. The coastal region of Brazil has achieved the goal proposed by the Seventh Conference of the Parties to the Convention on Biological Diversity - 7, but only then through the category V of the International Union for Conservation of Nature, which is not the best efficient means of conserving resources. The goal for marine conservation shows only the area above the recommended under protection in North Platform. The Marine portion of the East Coast and the South Platform has few protected areas, regardless of category management. We consider the coastal region the range of 12 nautical miles from baselines determined in accordance with the United Nations Convention on the Law of the Sea. As for the number of strategies permitted by law and used for the conservation of coastal and marine systems, coastal systems show a higher number when compared with the marine system. We suggest that the Brazilian government should specify strategies for the protection of marine systems and expand the protected areas of all Large Marine Ecosystems. © 2013 Elsevier Ltd.

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The Iguape and Cananéia Lagoon-Estuarine Complex is a biodiversity hotspot in southeastern Brazil. In recent decades, the region has become an important destination for recreational fishing. The objective of this study was to analyze the socioeconomic characteristics of visiting anglers and fishing guides working in the Cananéia-Iguape-Peruíbe Environmental Protected Area and their views on fisheries management. Data were collected through semi-structured interviews conducted between January 2009 and January 2010. We interviewed 278 anglers, who were predominantly male (93%) with a mean age of 47 years and from the state of São Paulo. The targeted species were snooks (Centropomus undecimales and Centropomus parallelus) and weakfishes (Cynoscion leiarchus and Cynoscion acoupa). Only half the anglers had the mandatory fishing license, and many of them lacked knowledge about catch quotas and minimum size requirements for specific species. The fishing guides (n = 80) were all male, with a mean age of 39 years and extensive experience. Most of the guides believe that the study area is somewhat degraded due to the removal of riparian vegetation, siltation, pollution, and especially the depletion of fish stocks. The opinions of the stakeholders (anglers and guides) converge on the high priority needs of the fishery and possible management actions regarding recreational fishing, such as improved fisheries enforcement (first in order of importance), proper training of fishing guides, zoning of fishing areas, and the definition of a maximum size limit. © 2013 Elsevier Ltd.

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This study investigated the hematological parameters of the tropical estuarine fish Centropomus parallelus and their use as a non-destructive biomarker for aquatic pollution. Individuals were collected, in summer and winter, at two estuaries, Cananéia (CAN) and São Vicente (SVE), and blood was extracted by caudal puncture. The evaluated parameters were hematocrit (Ht), red blood cells (RBC), Mean Corpuscular Volume (MCV), and the leukocyte (WBC) and thrombocyte counts. Fishes from CAN showed higher values of absolute number of thrombocytes in the summer. The fishes from SVE presented lower values of Ht and MCV in winter. Comparing the hematological parameters of fishes from these two sites, Ht, MCV, WBC and RBC were higher in fishes from SVE in the summer, whereas during the winter, Ht and thrombocytes were higher in animals from SVE. The results allow attributing the changes in the blood of fishes to seasonality and the presence of contaminants.

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Conclusiones y recomendaciones del Seminario cuyo objetivo fue analizar los problemas del campesinado andino en ecosistemas de altura relacionados con la penetración del estilo de desarrollo predominante en Latinoamérica, resaltando los complejos influjos recíprocos entre la oferta ambiental de recursos, las particularidades de los distintos pisos ecológicos, las formas y sistemas de organización social, los cambios y tendencias de la situación ambiental, para recomendar políticas de desarrollo que sean opciones viables para resolver los problemas del campesino de esas áreas. Incluye lista de participantes y documentos presentados.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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O objetivo deste estudo foi avaliar as concentrações de mercúrio total em penas de Ardea albus coletadas em uma assembléia de aves localizada nas imediações da cidade de Belém, Pará, com vistas a investigar a possibilidade do uso desta espécie nos estudos de biomonitoramento deste metal. Para determinação de mercúrio total foi utilizada a espectrofotometria de absorção atômica com amalgamação. A concentração média de mercúrio total nas penas do corpo foi 2,2 ± 1,5 µg.g-1 e nas penas das asas foi 1.3 ± 0.9 µg/g-1. Não foi observada correlação entre a concentração de mercúrio total e o comprimento das penas do corpo e da asa. Foi observado teor de mercúrio total superior a 5 µg.g-1 em apenas uma amostra de pena do corpo.

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O estudo de comunidades de peixes estuarinos tem recebido a atenção de pesquisadores, pelo fato destes ecossistemas apresentarem uma grande variedade e abundância de peixes. Muitas destas espécies possuem interesse comercial, constituido-se numa ferramenta fundamental para a avaliação dos estoques pesqueiros, contribuindo também para a conservação dos ambientes estuarinos e costeiros. O estuário do rio Curuçá localiza-se na costa norte, região do salgado paraense, apesar da pesca ser a principal atividade econômica das cidades da região, existem poucos estudos a respeito da ictiofauna local. O objetivo principal deste trabalho foi de caracterizar a ictiofauna demersal dos canais principais do estuário do rio Curuçá, identificando as variações anuais e espaciais na composição, densidade e biomassa, bem como os fatores abióticos que influenciam nestas variações. Para isto, foram realizadas coletas bimestrais, utilizando uma rede de arrasto de fundo, nos dois canais principais do estuário. Ao final do estudo foram capturados 18.989 indivíduos, pertecentes a 73 espécies, destas Ophichthus cylindroideus, Hippocampus reidi, Sygnathus pelagicus e Butis koilomatodon ainda não haviam sido registradas para a costa norte. As famílias Sciaenidae, Engraulidae e Ariidae, foram as mais representativas em número de espécies, densidade e biomassa, dominando as capturas. As 20 espécies classificadas como estuarinas foram a maioria, e apresentaram as maiores densidades e biomassa em todos os meses e estações de coleta. A densidade média (0,12 ind/m²) foi significativamente maior na estação chuvosa, já para a biomassa (1,11 g/m²) não houve diferenças significativas entre os meses de coleta. Entre os perfis, Curuçá apresentou uma maior riqueza de espécies, densidade e biomassa. Esta diferença está relacionada principalmente a uma maior heterogenidade de substratos deste perfil, fazendo com que este possua uma maior disponibilidade de microhabitat. Os parâmetros físicos-químicos da água se apresentaram homogêneos ao longo dos pontos de coletas tendo pouca influência sobre a distribuição espacial da ictiofauna. O fato de encontrarmos novos registros de espécies para a região, reforça a importância de novos estudos para uma maior compreensão da ictiofauna local, que é um importante recurso econômico para as populações locais.