A STUDY OF THE DISTRIBUTION AND ACTIVITY OF MICROORGANISMS IN OCEAN WATER1

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 bio-mass estimates based on ATP determinations gave reasonable results in relation to phyto-plankton biomass, total particulate organic carbon, and total particulate volume as deter-mined by an electronic particle counter. Respiratory rate estimates based on 0, 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 com-pounds 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