Nanophytoplankton
are free-floating, aquatic plant; contains algae, protists, and
cyanobacteria; photosynthetic, autotrophic plankton. They have chlorophyll in
their cells.
The main difference between nanophytoplankton and plankton is its smaller
size (2-20 nm versus >50 nm). Nanophytoplankton fix large amounts of carbon, which would otherwise be released as carbon dioxide.