Plankton Definitions

Microplankton
Picophytoplankton -unicellular, photosynthetetic mircobes (can be euks) up to 2 -3 microns
Phytoplankton - photosynthetic
Nanoplankton
Oligotrophic, mesotrophic, eutrophic
Euks bigger than 6 micrometers are important in coastal waters.
In open oceans, Prochlorococcus dominate the oligotrohpic layers. Prochlorococcus are smaller (get size) than Synechococcus, maybe in oligotrophic waters smaller is better, better volume to surface ratio.
Prochlorococus have definate nitrogen source utilization niches (no nitrate utilization, check this).Check to see about TOC homologues (of the TIC/TOC transporter)
Pico N2 fixers in ocean are single cell, Chrocosphaera and Cyanothece
Looks up Syn and Pro group designations - Scanlan, Bhattacharya, Syn CII, Pro HLII

Acaryochloris symbiont of a sea squirt, has Chl D

Pro MED 4, phage PodovirusP-SSP7 (Lindell)

Zehr, 2004 4 open ocean nitrogen fixers:
Trick - free living filamtentous N2 fix day
Rich - Symbiotic, filamentous
Cyanthoece - Symb(?), unicellular (Gr A) N2 fix duing day, more abundant than trick.
Synehcococcus WH 8501 (Crocosphaera) free living, unicelluar (Gr B) N2 fix night
Proteobacter
A&B down through 150 meters