G. Bratbak
Department of Microbiology, University of Bergen, Jahnebakken 5,
N-5020 Bergen, Norway.
Virus and virus like particles have been observed in about 50 different algal species but few algal-host-virus systems have been brought into culture and studied. The possible ecological significance of viruses has been inferred from the presence of algal cells containing virus like particles in natural communities, the presence of viruses in natural waters infecting specific algal populations and from studies of algal and virus population dynamics. Laboratory experiments with Phaeocystis pouchetii and the lytic virus PpV01 show that P. pouchetii is susceptible to virus infection in both exponential and stationary growth phase. Virus reproduction and cell lysis was not inhibited by nutrient (N or P) or light limitation, but inferior growth conditions caused a decrease in burst size of >50%. Viral infection allowed primary production in the cells to continue throughout most of the lytic cycle. During lysis of the algal cells the entire algal biomass was converted to DOC, which was efficiently utilized for bacterial biomass production.