Oxygen and carbon isotopic composition and biogeographic distribution of planktonic foraminifera in the Indian Ocean

International audienc

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