890 resultados para coastal aquifers
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The communities of brachyuran crabs living on soft bottoms off Ubatuba in SE Brazil were studied with respect to their structure, bathymetric distribution, composition, diversity and indices of similarity. The data were analyzed using multivariate techniques of classification and ordination. Most of the individuals caught during summer were the swimming crab Portunas spinicarpus at the 35 m isobath, which contributed to the much-decreased diversity in this season and site. Multivariate analysis indicated that the species were distributed according to depth and also in relation to environmental gradients.
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Elemental composition and spectroscopic properties (FT-IR and CP/MAS C-13-NMR) of sedimentary humic substances (HS) from aquatic subtropical environments (a lake, an estuary and two marine sites) are investigated. Humic acids (HA) are relatively richer in nitrogen and in aliphatic chains than fulvic acids (FA) from the same sediments. Conversely, FA are richer in carboxylic groups and in ring polysaccharides than HA. Nitrogen is mostly present as amide groups and for lake and marine HS the FT-IR peaks around 1640 cm(-1) and 1540 cm(-1) identify polypeptides. Estuarine HS exhibit mixed continental-marine influences, these being highly influenced by site location. Overall, the data suggest that aquatic and mixed HS are more aliphatic than has been proposed in current models and also that amide linkages form an important part of their structural configuration.
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The present study analyzed the composition of the aquatic fauna associated to the mangrove forest in a southeastern Brazilian river. The composition of the macrofauna in the roots of the marginal vegetation located at three different salinity stretches was analyzed by sampling pieces of the submerged branches of the vegetation (natural substrate) and pieces of sisal rope (artificial substrate), installed close to the natural vegetation and sampled after a period of 14 colonization days. In both types of substrate, twelve taxonomic groups were sampled, representing three phyla (Cnidaria, Annelida and Arthropoda). The crustaceans, corresponding to the most diversified group, were represented by Copepoda, Tanaidacea, Isopoda, Amphipoda and Decapoda. The highest salinity stretch showed the highest abundance, with a progressive decrease from high to low salinity for both substrates. Copepoda and Tanaidacea predominated on both substrates, although the artificial substrate exhibited the highest total abundance and species richness. Considering the relative abundance of the taxonomic groups on both substrates, the majority of groups predominated in the highest salinity range. Significant differences on the longitudinal distribution of abundance were associated to the variation on salinity and with the complexity of the substrate.
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The diversity of tropical forest plant phenology has called the attention of researchers for a long time. We continue investigating the factors that drive phenological diversity on a wide scale, but we are unaware of the variation of plant reproductive phenology at a fine spatial scale despite the high spatial variation in species composition and abundance in tropical rainforests. We addressed fine scale variability by investigating the reproductive phenology of three contiguous vegetations across the Atlantic rainforest coastal plain in Southeastern Brazil. We asked whether the vegetations differed in composition and abundance of species, the microenvironmental conditions and the reproductive phenology, and how their phenology is related to regional and local microenvironmental factors. The study was conducted from September 2007 to August 2009 at three contiguous sites: (1) seashore dominated by scrub vegetation, (2) intermediary covered by restinga forest and (3) foothills covered by restinga pre-montane transitional forest. We conducted the microenvironmental, plant and phenological survey within 30 transects of 25 mx4 m (10 per site). We detected significant differences in floristic, microenvironment and reproductive phenology among the three vegetations. The microenvironment determines the spatial diversity observed in the structure and composition of the flora, which in turn determines the distinctive flowering and fruiting peaks of each vegetation (phenological diversity). There was an exchange of species providing flowers and fruits across the vegetation complex. We conclude that plant reproductive patterns as described in most phenological studies (without concern about the microenvironmental variation) may conceal the fine scale temporal phenological diversity of highly diverse tropical vegetation. This phenological diversity should be taken into account when generating sensor-derived phenologies and when trying to understand tropical vegetation responses to environmental changes.
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Seasonal variation in gross primary production (GPP) of Utricularia foliosa Linnaeus, Egeria densa Planchon and Cabomba furcata Schult & Schult.f. in rivers of the coastal plain of the state of São Paulo, Brazil was examined in relation to water physico-chemistry. These three species do not affect the multiple uses of the streams and are present throughout the year. The most productive was U. foliosa (maximum production 24.7 mgO(2) g(-1) DW h(-1)), while C. furcata had an intermediate GPP (maximum production 17.5 mgO(2) g(-1) DW h(-1)) and E. densa was lowest at 5.6 mgO(2) g(-1) DW h(-1). Despite the low amplitude of seasonal variation in this south tropical area, the three species showed seasonal variation in the primary production: GPP was positively correlated with photosynthetic active radiation for U. foliosa and E. densa, and there was a negative correlation for C. furcata. For U. foliosa, GPP was positively correlated with temperature and dissolved inorganic carbon and the GPP of C. jurcata was positively correlated with dissolved inorganic carbon.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The main purpose of this research was to measure the condition of the fish species Hoplias aff. malabaricus collected in Aguapeu River (black waters) and Branco River (white waters), which belong to Itanhaem River basin, a coastal watershed in São Paulo state, Brazil. Individuals of Hoplias aff. malabaricus were sampled by using gill nets, monthly from March 2001 to February 2002. The Condition Factor was obtained through the length-weight relationship, assuming that the higher the mass for a given length, the better the condition of the fish. The Condition Factor was compared among fishes from both rivers, resulting that Branco River individuals have significantly lower condition. Limnological aspects were studied from May 2001 to November 2002 and some show significant differences between Aguapeu River and Branco River. These were salinity, do and total organic N, which the higher values being observed in Branco River propably due to estuarine waters influence. However, the lower condition of the Branco River fishes should also be an effect of a disturbance due to the sand mining in this river, since this activity cause important alterations to the environment, affecting the whole biota, included aquatic macrophytes, invertebrates and fishes.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Considering the great ecological importance of the cyanobacteria and the need for more detailed information about these organisms in Brazilian waters, this paper provides taxonomic information about the unicellular cyanobacteria flora in lagoon systems along the coastal plains of Rio Grande do Sul State. Sampling was performed in different freshwater bodies along the eastern (Casamento Lake area) and western (near the city of Tapes) banks of the Patos Lagoon (30º40' S-30º10' S and 50º30' W-51º30' W). The samples were collected once in the rainy season and once in the dry season (from May 2003 to December 2003) using a plankton net (25 µm mesh) in pelagic and littoral zones, and by squeezing the submerged parts of aquatic macrophytes. Thirty one species belonging to the families Synechoccocaceae (7 taxa), Merismopediaceae (12 taxa), Chamaesiphonaceae (1 taxon), Microcystaceae (4) and Chroococcaceae (7 taxa) were identified. Among these species, five are reported for the first time in Rio Grande do Sul State: Chamaesiphon amethystinus (Rostafinski) Lemmermann, Chroococcus minimus (Keissler) Lemmermann, Coelomoron pusillum (Van Goor) Komárek, Coelosphaerium kuetzingeanum Naegeli, and Cyanodictyon tubiforme Cronberg.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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As drenagens costeiras do leste do Brasil correspondem a áreas de grande significado biogeográfico, apresentando um alto grau de endemismo em sua fauna de peixes. Padrões filogenéticos sugerem uma relação próxima entre os rios que correm para o Atlântico a os adjacentes das terras altas do escudo cristalino. Entretanto, pouco tem sido dito sobre a dinâmica dos processos geológicos relacionados aos eventos cladogenéticos entre estas áreas. Padrões de distribuição e filogenéticos sugerem uma íntima associação com a história geológica da margem continental passiva da América do Sul, desde o Cretáceo aos dias atuais. Soerguimentos macrodômicos, rifteamento, movimentos verticais entre blocos falhados e o recuo erosivo da margem leste sul-americana são considerados como as principais forças geológicas atuando sobre a distribuição da ictiofauna de água doce nestas áreas. A atividade tectônica associada à ruptura do Gondwana e separação da América do Sul e África criou seis megadomos que são responsáveis por configurar a maior parte do atual curso das principais bacias hidrográficas do escudo cristalino. Com exceção das bacias localizadas às margens de tais megadomos, estes rios desenvolveram longos e sinuosos circuitos sobre o antigo escudo cristalino brasileiro antes de desaguarem no então recentemente aberto Oceano Atlântico. Eventos cladogenéticos iniciais entre drenagens de terras altas do escudo cristalino e tributários do Atlântico podem estar associados com processos vicariantes desta fase inicial, e alguns táxons antigos, basais, grupos-irmão de táxons muito inclusivos e de ampla distribuição são encontrados nestas bacias hidrográficas. Mais tarde, a denudação erosiva generalizada resultou em um ajuste isostático da margem leste da plataforma. Tal ajuste, concomitantemente a reativações de antigas zonas de falha, resultou em movimentos verticais entre blocos falhados, dando origem, no sudeste do Brasil, a bacias tafrogênicas. Tais bacias, como a de Taubaté, São Paulo, Curitiba e Volta Redonda, entre outras, capturaram drenagens e fauna de terras altas adjacentes. Os peixes fósseis da Formação Tremembé (Eoceno-Oligoceno da Bacia de Taubaté) exemplificam este processo. Outros sistemas tafrogênicos de idade Terciária foram também identificados em outros segmentos da margem continental Atlântica, como na Província Borborema, no NE do Brasil, com marcada influência sobre o padrão de drenagem. Ao mesmo tempo, o recuo erosivo da margem leste da plataforma capturou sucessivamente rios de planalto, os quais se tornaram tributários atlânticos, evoluindo associados aos principais sistemas de falha. A natureza continuada destes processos explica os padrões filogenéticos e de distribuição miscigenados entre os tributários atlânticos e as terras altas do escudo cristalino adjacente, especialmente na margem sudeste do continente, representados por sucessivos, cada vez menos inclusivos, grupos irmãos, associados a eventos cladogenéticos desde o final do Cretáceo ao presente.
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U-modeled groundwater residence times were estimated by changes in U-234/U-238 activity ratio (AR) and U content of groundwaters from Pocos de Caldas city situated at the Pocos de Caldas alkaline massif, Brazil. The estimated ages are more realistic than others generated by the use of hydraulic conductivity data and available information about the weathering rate of rocks in the plateau. The U-234/U-238 AR and reciprocal of the dissolved U-content data also defined a ternary plot that allowed the calculation of the relative volume of three source waters for the mixed water. Such U-isotopes modeling for mixing calculations indicated that the dominant phase (68%) in the mixture is thermal.
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A taxonomic study is provided for the angiosperm family Sapotaceae based on specimens collected on the coastal plains of Picinguaba, municipality of Ubatuba, State of São Paulo, Brazil. The samples were gathered monthly from 1988 to 1991 and are kept in the Herbarium Rioclarense (HRCB). Six species and five genera are here presented with descriptions, ilustrations and identification key.