DETERMINATION OF BACTERIOPLANKTON BIOMASS, NET PRODUCTION AND GROWTH EFFICIENCY IN THE SOUTHERN-OCEAN

Several conversion factors are required for the estimation of bacterial biomass, net production and carbon demand from epifluorescence microscopy and measurements of [H-3]-thymidine and [H-3]-leucine incorporation rates. These conversion factors were evaluated simultaneously in mixed cultures of bacterial assemblages from the Weddell/Scotia Confluence of the Southern Ocean. The cultures were grown in the dark at +1-degree-C. Conversion factors were calculated for each culture by regression analyses of cumulative parameters. Average conversion factors were: 1.1 X 10(18) cells per mol thymidine incorporated into cold TCA precipitate, 7.5 X 10(15)-mu-m3 of biovolume per mol leucine incorporated into cold TCA precipitate, 0.4 pgC biomass per mu-m3 of biovolume, and 40% carbon growth yield.