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°N at water-depths between 864 m and 4187 m to investigate the influence of extreme food scarceness in the perennially ice covered deep Arctic-Mediterranean on the meiobenthic community. Meiofauna densities (including foraminiferans) ranged between 68-247 ind·10 cm-2 in the uppermost sediment layers and were very low compared to values from temperate, central oceanic regions. Nevertheless, a decrease in abundance with increasing water depth as well as regional differences in abundance and community structure were detectable. Foraminiferans were by far the predominant taxon (58-86 %), followed by nematodes (10-27 %). Except for harpacticoid copepods all other meiofauna taxa occurred in extremely low densities and very patchy. Very low meiofaunal abundances and a visible trend towards miniaturisation of organisms may be an outcome of the extremely limited food supply to the benthos under perennial ice-coverage of the central Arctic Ocean.