Marine viruses and their biogeochemical and ecological effects

Viruses are the most common biological agents in the sea, typically numberi ng ten billion per litre, They probably infect all organisms, can undergo v apid decay and replenishment, and influence many biogeochemical and ecologi cal processes, including nutrient cycling, system respiration, particle sir e-distributions and sinking rates, bacterial and algal biodiversity and spe cies distributions, algal bloom control, dimethyl sulphide formation and ge netic transfer. Newly developed fluorescence and molecular techniques leave the field poised to make significant advances towards evaluating and quant ifying such effects.