Deep-sea meiobenthos of the central Arctic Ocean: distribution patterns and size-structure under extreme oligotrophic conditions

During the expedition "Arctic Ocean '96" with the Swedish icebreaker ODEN ( 18.07.-21.09.96), sediments were collected from 20 basin and ridge stations in the deep-sea regions of the central Arctic Ocean north of 85 degrees N at water-depths between 864 m and 4187 m to investigate the influence of ex treme food scarceness in the perennially ice covered deep Arctic-Mediterran ean on the meiobenthic community. Meiofauna densities (including foraminife rans) ranged between 68-247 ind.10 cm(-2) in the uppermost sediment layers and were very low compared to values from temperate, central oceanic region s. Nevertheless, a decrease in abundance with increasing water depth as wel l as regional differences in abundance and community structure were detecta ble. Foraminiferans were by far the predominant taxon (58-86 %), followed b y nematodes (10-27 %). Except for harpacticoid copepods all other meiofauna taxa occurred in extremely low densities and very patchy. Very low meiofau nal abundances and a visible trend towards miniaturisation of organisms may be an outcome of the extremely limited food supply to the benthos under pe rennial ice-coverage of the central Arctic Ocean.