Brussaard, C. P.D.. Univ. Bergen, corina.brussaard@im.uib.no
Bratbak, G. P.D.. Univ. Bergen, gunnar.bratbak@im.uib.no

 
VIRAL CONTROL OF PHYTOPLANKTON BLOOMS
 
Algal blooms represent accumulations of high amounts of particulate organic carbon and nutrients. Viral lysis will result in a sudden release of dissolved algal cellular components. Virus infection may thus not only have a direct effect on phytoplankton dynamics and diversity, but also an indirect effect by enhancing bacterial production. Phytoplankton cell lysis was found to influence the functioning and structure of the microbial food web. Nutrient remineralization and increased microzooplankton grazing will affect phytoplankton succession. Laboratory studies on the interaction between the bloom forming phytoplankter Phaeocystis pouchetii and the lytic virus PpV01 showed that DOC release during viral lysis was rapid and that it was efficiently utilized by bacteria. P. pouchetii was susceptible to virus infection in all stages of growth. Depletion of nitrate, phosphate did not prevent virus proliferation and cell lysis. Nor did light limitation. Length of lytic cycle was not affected, but burst size decreased with increasing depletion/limitation. The use of fluorescent viability dyes SYTOX and Calcein-AM allowed discrimination of dead and live phytoplankton cells. Flow cytometric analyses showed that virus infection could be detected as a change in forward light scatter, side light scatter and chlorophyll content of the algal cells.
 
Day: Wednesday, Feb. 3
Time: 10:30 - 10:45am
Location: Hilton of Santa Fe
 
Code: SS38WE1030H