High sympagic metazoan abundance in platelet layers at Drescher Inlet, Weddell Sea, Antarctica

Abstract

The metazoan fauna of platelet layers was investigated at Drescher Inlet, Weddell Sea, Antarctica in the late summer of 1995. Twenty-eight species were found, many of them new to science. The most abundant subclass was the Copepoda, of which almost 90% of the individuals belong to only three species: Drescheriella glacialis, Stephos longipes and Paralabidocera antarctica. Among copepods, Harpacticoida was the largest group, represented by 16 species. Total abundance varied between 40 and 120 individuals l⁻¹. Abundances and population structure were comparable to other especially porous sea-ice habitats. Results indicate competitive exclusion among the three dominant species. The finding of a profuse meiofauna in platelet layers may explain enigmatic concentrations of ammonium and phosphate commonly detected there.