Rotifera das zonas limnética e litorânea do reservatório de Tapacurá, Pernambuco, Brasil Rotifera from littoral and pelagic zones of Tapacurá reservoir, Pernambuco, Brazil

Os rotíferos do reservatório de Tapacurá, Pernambuco, Brasil foram estudados quanto à distribuição horizontal nas zonas limnética e litorânea, nos períodos chuvoso (agosto de 2003) e seco (janeiro de 2004). Amostras quali-quantitativas foram obtidas através de coletas em ritmo nictimeral nas distintas zonas do reservatório, com intervalo de seis horas, em duas profundidades. Os parâmetros bióticos riqueza, densidade, diversidade e equitabilidade foram avaliados. Análises de similaridade e variância (ANOVA) também foram utilizadas. Vinte e oito espécies e duas subespécies de Rotifera foram encontradas, das quais cinco espécies são novas ocorrências para Pernambuco. A zona litorânea apresentou maior riqueza que a limnética em ambos ao período sazonais, com nove espécies exclusivas. As diferenças de densidade e equitabilidade entre as zonas do reservatório não foram significativas, ao contrário da diversidade, que apresentou-se mais elevada na zona litorânea no período seco (p<0,01). A análise de similaridade revelou homogeneidade horizontal da comunidade de Rotifera no período chuvoso, caracterizado por menores temperaturas e maior velocidade do vento, e tendência à estratificação horizontal no período seco, caracterizado por temperaturas mais elevadas e menor intensidade dos ventos. A presença de macrófitas propiciou características peculiares na zona litorânea.<br>The rotifers of Tapacurá reservoir, State of Pernambuco, Brazil, were studied concerning the horizontal distribution in pelagic and littoral zones, in the rainy (August/2003) and dry seasons (January/2004). Qualitative and quantitative samples were carried out in nictimeral samplings in the different zones of the reservoir, with an interval of six hours in the two depths. Biotic parameters as richness, density, diversity and equitability were estimated. Similarity and Analysis of Variance (ANOVA) were also used. Twenty-eight species and two subspecies of Rotifer were found from which five species are considered new occurrences in State of Pernambuco. The littoral zone presented higher richness than the limnetic zone in both seasonal periods with nine exclusive species. The density and equitability differences between zones of the reservoir were not expressive in opposite to diversity that was higher in the littoral zone in the dry season (p<0.01). The similarity analysis indicated horizontal homogeneity of Rotifer community in the rainy season characterized by lower temperatures and higher wind velocity, and a tendency to horizontal stratification in the dry season characterized by higher temperatures and lower wind intensity. Presence of aquatic vegetation yielded peculiar features in the littoral zone

Pteropoda (Gastropoda, Thecosomata e Gymnosomata) coligidos ao largo dos arquipélagos de São Pedro e São Paulo, costa nordeste, Brasil Pteropoda (Gastropoda, Thecosomata and Gymnosomata) collected along the northeast coast of the archipelago of São Pedro and São Paulo, Brazil

<abstract language="eng">Pteropoda studies were carried out offshore São Pedro and São Paulo Archipelago (0º56'2"N e 29º20'6"W) to assess biodiversity and spatial distribution. A Bongo net (mesh size 300 micrometer) was hauled obliquely from a depth between 0 and 50 m and Oand 100 m by the REVIZEE-SCORE/NE I oceanographic expedition on board of the Brazilian Navy Oceanographic Ship Antares. Samples were collected at 16 stations from September to October 1995. A total of 880 organisms distributed in 20 species, 14 genera and 9 families were identified. At the layer 0-50 m, Creseis virgula (Rang (828) was the most frequent species (71.43%), followed by Limacina inflata (Orbigny, (836) and Cavolinia inflexa (Lesueur, 18(3) (64.28%, each). ln terms of relative abundance outranked L. inflara (varying between 57.5 and 92.24%) and C. virgula (varying between 60.0 and 72.73%). At the layer 0-100 m, C. virgula was very frequent (80%), L. inflata (70%) and Cuvierina columnella (Rang (827) (40%) were frequent, other species had less than 30% of frequency. L. inflata varied from 37.5 to 100% and C. virgula from 42.42 to 100% of relative abundance. Species diversity varied from medium to low ( < 2.0 bits.ind-1) in both layers. At the layer 0-50 m C. virgula was directly correlated to temperature and salinity, while at the layer 0-100 m L. inflata was correlated to these parameters, showing that these species are Tropical Water indicators