ABSTRACT
Studies about the relationship of the species of appendicularians with spatial gradients and water masses are rare, especially in the South Atlantic. The present study aims to fill the knowledge gap about the abundance of the community of appendicularians and on their bioindicator function in different regions (continental shelf and slope), with influence of different water masses in the South Atlantic. Sampling was conducted in the rainy season (February-April 2009) and the dry season (August-September 2009) in the subsurface layer. The water masses found on the continental shelf of the study area were the Tropical Water (AT), which was prevalent during the rainy season, and the Coastal Water (AC), which was prevalent in the dry season. In both sampling periods has not registered the presence of SACW on the surface over continental shelf. The appendicularians were more abundant in the region of the continental shelf influenced by the CW. A total of 18 species of appendicularian was registered. Oikopleura longicauda Vogt, 1854 and O. fusiformis Fol, 1872 were the most abundant appendicularian. Oikopleura dioica Fol, 1872 was found exclusively in the continental shelf on the CW. In despite of the SACW water had not registered on the surface, the presence of, high values of density of appendicularians in front of Cabo Frio region suggest the influence of an upwelling event in a anterior period in the region. In relation to the appendicularians abundance, high values were also observed in front of the Paraíba do Sul river with the CW influence. This fact suggests a high nutritional contribution of this river in the coastal marine area adjacent. The spatial variation and different water masses influenced the abundance and the composition of appendicularians. Among the species identified, only O. longicauda was considered as a bioindicator of the CW.
KEYWORDS
Zooplankton; Oikopleura; Fritillaria; Southwestern Atlantic
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