Abstract
Viruses and virus-like particles (VLP) have been found, in most cases perchance, in about 20 marine phytoplankton species. However only in six of these have there been further investigations on this phenomenon. Different mechanisms of interaction have been hypothesized. These include continuous dynamic viral control on populations (Synechococcus spp.), at times suppressed by external environmental factors (Aureococcus anophagefferens), termination of a bloom caused by viral infection (Emiliania huxleyi and Micromonas pusilla) or by induction of lysogenic cells (Heterosigma akashiwo), and effects on the survivability of specific clones through genetic control (Aureococcus anophagefferens). These examples illustrate the complexity of virus-algae relationships and provide an indication that they may represent a key factor in the dynamics of phytoplankton blooms.