Seasonal carbon distribution of copepods in the eastern Weddell Sea, Antarctica

Copepods were sampled by a multiple opening-closing net in the eastern Wedd ell Sea during various seasons (late winter/early spring, summer, autumn). Total copepod biomass integrated over the upper 1000 m varied seasonally be tween 1.7 mg C m(-3) in late winter/early spring and 3.7 mg C m-3 in autumn . After the dark season the copepods were rather evenly distributed vertica lly and highest biomass levels were found in the mid-water layers between a bout 200 m and 500 m. By contrast, especially in summer but also in autumn copepod biomass concentrated in the uppermost water layer. A total of 64 ca lanoid species were identified in the upper 1000 m with maximum species num bers in the deepest layer. The large calanoids Calanus propinquus, Calanoid es acutus, Metridia gerlachei, Euchaeta antarctica and the small calanoid M icrocalanus pygmaeus prevailed and accounted for 60-70% of total copepod bi omass, while the small poecilostomatoid Oncaea and the cyclopoid Oithona sp ecies comprised about 20%. Hence, the distribution pattern of the entire co pepod biomass is strongly influenced by the life cycles of a few dominant s pecies.