A study of the distribution and activity of microorganisms in ocean water

Abstract

Estimates of living mass and respiratory rate were made by several methods on large water samples taken at several depths at each of two ocean stations. Total microbial biomass estimates based on ATP determinations gave reasonable results in relation to phytoplankton biomass, total particulate organic carbon, and total particulate volume as determined by an electronic particle counter. Respiratory rate estimates based on O2 uptake, electron transport system activity, and ATP were in moderately good agreement in surface water but diverged widely in deep water. Heterotrophic uptake of specific organic compounds seems to be related to numbers of active bacteria and not related to total microbial respiration. Photosynthetic rates and release of dissolved photosynthate are reported for both stations.