Question

who is the most abundant microorganism

Answer 1

If you had to guess the most abundant organism on the whole planet, you'd probably think of ants or, maybe, bacteria. But a newly discovered virus might trump them all. Pelagibacter ubique is often cited as the most common organism ever: it's a third of all the single-celled organisms in the ocean.

Answer 2

the most abundant microorganism is pelagibacter.