There are a ridiculous number of microbes in the Earth’s oceans.
During an 11 month study in 2007, scientists sequenced the genes of more than 180,000 specimens from the Western English Channel. Although this level of sampling “far from exhausted the total diversity present,” they wrote, one in every 25 readings yielded a new genus of bacteria (7,000 genera in all).
That’s genus, not species. Kevin Kelly translates:
This suggests there is a long tail of life in bacteria, with a few species super-abundant, but many many species with very thin populations. At the far end of the tail there may be a billion species with only a few individuals. […] And like other kinds of long tails, the sum of all these small bits total up to exceed the sum of individuals in the most popular species. As the microbiologists involved in the Census of Marine Life like to say, this survey reveals life’s “hidden majority.”