Fact: there are 10 viral (bacteriophage*) particles for every bacterial particle in the ocean. And it's more than that in certain micro-environments. Not all 10 are necessarily the same kind of virus either, as hosts and parasites are often specific to each other and many different types of bacteria exist in the oceans.
*Bacteriophage literally means "to devour bacteria" (think of the word "phagocytosis"- same root). They are a class of viruses that attack bacteria and break open the cells for their own [amusement and] replication. Thus, all bacterial cells are in a dance with death!