Bacterial standing stock and consumption of organic carbon in the benthic boundary layer of the abyssal North Atlantic

Abstract

Annual changes in bacterial biomass and remineralization of 14C-labelled cultured algae (Synechococcus sp.) were investigated. Sediment bacterial biomass increased seasonally in response to sedimentation of organic matter. Most of the total integrated bacterial biomass from surface waters to deep-sea sediments is contained in the sediments, while bacterial activity in these sediments is lower than suggested by the high biomass concentrations. The complex organic matter of the added algal material was remineralized by sediment bacteria under simulated deep-sea conditions at rates of 0.6-2.3% d-1 during the initial rapid degradation phase of c400 hrs. Under in situ pressure, more of the organic matter was consumed than at 1 atm. -from Author