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Vertical Copepod Assemblages (0-2300 m) off Southern Brazil

2010; Biodiversity Research Center, Academia Sinica; Volume: 49; Issue: 2 Linguagem: Inglês

1810-522X

Cristina de Oliveira Dias, Adriana Valente de Araújo, Rodolfo Paranhos, Sérgio Luiz Costa Bonecker,

Isotope Analysis in Ecology

The structure of copepod assemblages in the region of the Campos Basin was studied for a 1 yr period. Zooplankton samples were obtained in the 2002 wet season and 2003 dry season, by stratified vertical hauls in 4 previously identified water masses: tropical water (TW), South Atlantic central water (SACW), intermediate Antarctica water (IAW), and North Atlantic deep water (NADW). Temperature and salinity were determined. The copepod mean density did not significantly differ (p＜0.05) between the northern and southern stations in the 2 seasons, but significantly differed among the water masses, and in each water mass in the 2 seasons, except for the SACW. The highest mean density was found in the TW, and the lowest in the NADW. Eighty-nine taxa of copepods, with 70 generally distributed species and 19 species exclusive to 1 or another water mass were recorded in the 4 water masses. The copepod assemblages of the Campos Basin showed tropical characteristics, and were numerically dominated by epipelagic species: Clausocalanus furcatus, Farranula gracilis, and Oncaea venusta in TW; Pleuromamma abdominalis, Macrosetella gracilis, Oncaea venusta, and Clausocalanus furcatus in the SACW; Clausocalanus furcatus, Oncaea venusta, Triconia conifera, and Calanoides carinatus in the IAW; and Oncaea venusta, Oithona similis, Clausocalanus furcatus, Farranula gracilis, and Mecynocera clausi in the NADW. Differences in the copepod community along the water column were found. Differences in copepod compositions and abundances were possibly a consequence of the influences of oceanic and shelf waters, with contributions of deep-water species to the upper-level water masses. Despite the oligotrophic nature of the Brazil Current, the densities found were higher than those observed along the Brazilian coast and in other tropical regions.