The ecology and biogeography of Tintinnid ciliates in the Atlantic Sector of the Southern Ocean.

ALDER, V.A.; BOLTOVSKOY, D.

MARINE CHEMISTRY

Elsevier Science Publishers B.V,

Año: 1991 vol. 35 p. 337 - 346

0304-4203

Qualitative and quantitative analyses of the tintinnids retrieved in surface and vertical (down to 1150 m) samples in the Scotia, Weddell, Bransfield and Bellingshausen areas allow defining three distinct zones: (A) Scotia Sea, Bransfield Strait and oceanic waters of the northern-central Weddell Sea, dominated by Codonellopsis gaussi and Cymatocylis affinis/convallaria; (B) Shelf and mostly ice-covered areas of the southernmost Weddell Sea and the Bellingshausen Sea, characterized by Laackmanniella prolongata and Cymatocylis drygalskii; (C) Bransfield-Weddell waters around the tip of the Antarctic Peninsula, where Codonellopsis balechi accounts for 80% of the tintinnids. These areas have (often significantly) different ice regimes, water-column depths, surface salinities, bulk planktonic settling volumes and microplanktonic concentrations. On the other hand, the composition of tintinnid assemblages is very similar on both sides of the Antarctic Peninsula. Causal interpretations for these heterogeneous distribution patterns and probable specific adaptations to the dissimilar environmental settings involved are analyzed.