Incorporation of viruses into the budget of microbial C-transfer A first approach

Abstract

Viral lysis of bacteria has been suggested to be a quantitatively important process in the removal of bacteria, and potentially also in the production of DOC, in the ocean. In order to investigate the quantitative role of viruses in the pelagic microbial ecosystem, a die1 study was undertaken, comprising measurements of particulate and dissolved primary production, bactenal production, bacterial grazing by flagellates, bacterial lysis by viruses, and production of viruses. Estimates of algal excretion (4.7 pm01 C 1-' d-I) and bacterial carbon consumption (3.0 pm01 C I-' d-l) were in reasonable balance. Predation (2.9 pm01 C 1-' d-l) exceeded bacterial production (1.5 pm01 C 1-' d-l) estimates by a factor of 2. Major difficulties in balancing the budget emerged however, from the estimates of vual lysis of bacteria (9.2 pm01 C I-' d-l), which exceeded bacterial production by a factor of 6. Despite these problems, results support the idea that viral lysis may b e a quantitatively significant process that needs to b e incorporated into budgets of microbial C-transfer.