Natural bacterial assemblages in deep-sea sediments: towards a global view

Abstract

Examined existing data on bacterial biomass in sediments across the entire depth range of the oceans, along with a smaller data set from abyssal North Atlantic and Arctic basins. The latter included measures of bacterial biomass, utilization rates of dissolved amino acids, and the supply of particulate organic carbon to the seafloor. Statistical analysis indicated ocean depth to be a weak predictor of bacterial parameters, while the magnitude of organic carbon flux to the seafloor proved a strong one. The missing factor in our understanding of bacterial activities in deep-sea sediments is the quality or hydrolytic potential of the organic carbon supply to the seafloor. High-latitude basins, from which the highest benthic bacterial biomass and activity rates were recorded, should provide ideal sites for testing hypotheses on the bacterial fate of organic carbon in the deep sea. -from Authors