NEMATODE DISTRIBUTION IN OCEAN MARGIN SEDIMENTS OF THE GOBAN SPUR (NORTHEAST ATLANTIC) IN RELATION TO SEDIMENT GEOCHEMISTRY

Nematode density along a depth gradient (206-2760 m) in the northeaste rn Atlantic (Goban Spur) is linearly and positively related to organic matter mineralization in the sediment. It is estimated that nematodes contribute at most 13% to total carbon turnover, and this contributio n decreases with water depth. The vertical distribution df nematodes i n the sediment closely follows concentration vs depth profiles of tota l nitrogen in the sediment. Both nematodes and total nitrogen tend to be more concentrated towards the surface with increasing water depth. There is no indication that nematode vertical distribution is directly influenced by the oxygen penetration in the sediment. However, it is hypothesized that the sediment oxygen concentration dan explain the re latively greater importance of smaller organisms in benthic communitie s with increasing water depth. The nitrogen vs sediment depth profiles are consistent with a greater impact of larger organisms on sediments at the shallow stations and decreased sediment mixing with increasing water depth. (C) 1997 Elsevier Science Ltd.