Relationships between tintinnid and copepod specific abundances in the Drake Passage and Bellingshausen Sea

ESTELA DINOFRIO; LUCIANA SANTOFERRARA .; GUILLERMO VISBEEK; VIVIANA A. ALDER

Curitiba, Brasil

Simposio; IX SCAR Biology Symposium: Evolution and biodiversity in Antarctica; 2005

SCIENTIFIC COMMITTE ON ANTARCTIC RESEARCH (SCAR)

The relationships between tintinnids, copepods and environmental factors were analyzed for 25 sub-surface samples collected between 56.5ºS and 68ºS by the iceabreaker Almirante Irizar during April 2002. At each station, two series of samples were collected; one was preserved with 50% Bouin solution for loricate ciliates, and the other with 2% formaldehyde for copepods, which were examined qualitatively and quantitatively under inverted microscope and steromicroscope, respectively. Tintinnids were represented by 12 genera, 21 species and 10 formae, while copepods included 9 genera and 7 species. The former reached, in average, 34 ind l-1, with Codonellopsis gaussi f. cylindroconica and Laackmaniella naviculaefera f. naviculaefera representing 50% and 25% of tintinnids´ total  abundance, respectively. Highest contribution to total copepods (mean: 8.1 ind. l-1) was found for nauplii (90%), followed by the stage II of Oithona similis (7%). Three biogeographic zones were delimited on the basis of tintinnid and copepod species abundances: Subantarctic Drake Passage, Antarctic Drake Passage-Northern Bransfield Strait, and Southern Bransfield Strait-Bellingshausen Sea.