Larval dispersal of Brachyura in one of the largest estuarine/marine systems in the world.

The Amazon Continental Shelf (ACS) is a complex habitat that receives a large annual freshwater discharge into the ocean, producing a superficial plume and carrying with it large amounts of nutrients to the continental shelf along thousands of kilometers while sustaining high biodiversity in the estuary-ocean continuum. For the first time, this study monitored six sites in a wide transect with approximately 240 km radius on the ACS every 2-4 months. The objectives were (1) to analyze the composition of larval Brachyuran crabs and (2) to predict the importance of environmental parameters (temperature, salinity and chlorophyll-a) in structuring their abundance. A total of 17,759 larvae identified were distributed in 8 families and 24 taxa. The water salinity was the best predictor of larval distribution. The statistical models used indicated that Panopeidae and Portunidae larvae are more frequent and more likely to occur in shallow water layers, while Calappidae occur in deeper layers, and Grapsidae, Ocypodidae, Sesarmidae, Pinnotheridae and Leucosiidae occur similarly in both strata. The larval dispersal extent varies among families and throughout the year while the groups are distributed in different salinities along the platform. The probability of occurrence of Portunidae is higher in ocean water (≥ 33.5); Grapsidae, Panopeidae, and Pinnotheridae is higher in intermediate and ocean salinity waters (25.5 to 33.5); Ocypodidae, Sesarmidae and Calappidae is higher in estuarine and intermediate salinity waters (5 to 25.5), whereas Leucosiidae, euryhaline, occur in all salinities (5 to 33.5). Furthermore, the Amazon River seasonal flow and plume movement throughout the year not only regulate the larval distribution and dispersion of estuarine species but are also fundamental for the ACS species, providing the necessary nutrient input for larval development in the region.

A modeling approach for reposition dynamics of litter composition in coastal areas of the city of Santos, Sao Paulo, Brazil.

Given the complexity of the dynamics in litter reposition, our objective was modeling the possible main and interaction effects of tidal oscillations, seasons of the year and the moon phases over the solid waste in Santos beaches. A total of 80 collections were carried out using quadrat sampling, from which we classified, counted and weighed all residue items. We fitted mixed Hurdle models to the output datasets and performed hypotheses tests based on this framework. We found plastic to be the most abundant residue in all seasons, moon phases and tides, followed by Styrofoam and wood. Our models suggest the strongest effect was due to seasonal variations, which, in turn, may be related to different human activities. Although the dynamics of different components showed independency of all interaction structures, plastics depended on the interaction of tide and season, whose impact over estuarine life and ecosystem services shall be further investigated.

Evaluation of the Atibaia River water quality using Lecane bulla as a test organism / Avaliação da qualidade das águas do Rio Atibaia usando Lecane bulla como organismo teste

In view of the diversity of environments found in the Brazilian territory, it is understandable that the use of native species can provide more relevant information for ecotoxicological studies. The purpose of this work was to evaluate the quality of water samples from the Atibaia River in an area that is under the influence of petroleum refinery using a native test-organism and submitting the data to PCA statistical analysis. Therefore, acute toxicity assays with Lecane bulla (Rotifera) were performed in four locations of the river, as well as physical-chemical analyses. Sampling was drawn in the dry and rainy seasons. The bioassays were static and lasted 48 hours; dead organisms were quantified at the end of the tests. Toxicological differences among the samples/per location and control were compared by means of the Analysis of Variance. Physical-chemical and mortality variables were simultaneously analyzed by multivariate analysis of the principal components and the Pearson correlation coefficient. Water samples from the exit of the refinery stabilization pond (location S.1) were toxic to L. bulla in both seasons, with significant differences in relation to the control and between the seasons. The statistical treatment of data showed that mortality was strong and positively correlated with total hardness, chlorides and EC, which together with pH presented higher values in location S.1, in the dry and in the rainy seasons. Due to its sensibility to the quality of the Atibaia river water samples, the potential use of L. bulla for ecotoxicological studies as an alternative test organism could be demonstrated.(AU)

Em virtude da diversidade de ambientes encontrada no território nacional, o uso de espécies nativas em estudos toxicológicos constitui assunto de extrema relevância. Este trabalho objetivou avaliar a qualidade das águas do rio Atibaia, em uma região sob influência de uma refinaria de petróleo utilizando-se um organismo-teste nativo, e aplicando-se o método estatístico multivariado análise de componentes principais (PCA). Ensaios de toxicidade aguda com o rotífero Lecane bulla (Rotifera) e análises físico-químicas foram realizados com amostras obtidas em quatro diferentes pontos do rio em questão. As amostragens ocorreram nas estações seca e chuvosa. Os bioensaios foram estáticos e duraram 48 horas; organismos mortos foram quantificados no final dos testes. Diferenças toxicológicas entre as amostras de cada ponto e o controle foram comparadas por análise de variância. As variáveis físico-químicas e a mortalidade foram simultaneamente submetidas à análise multivariada dos componentes principais e pela correlação de Pearson. Amostras de água retiradas da saída da lagoa de estabilização (ponto S.1) foram tóxicas ao organismo L. bulla nas duas estações, com diferenças significativas em relação ao controle e entre as estações. O tratamento estatístico dos dados demonstrou que a mortalidade correlacionou-se forte e positivamente com parâmetros como dureza total, cloretos e EC, e, com o pH, apresentou valores maiores no ponto S.1 em ambas as estações. A sensibilidade apresentada pela espécie L. bulla em relação à qualidade das amostras da água do rio Atibaia indicou que este organismo apresenta potencial de uso para estudos de ecotoxicologia, podendo ser futuramente empregado como organismo-teste alternativo.(AU)