TY - JOUR T1 - Small phytoplankton dominate western North Atlantic biomass A1 - Bolanos,Luis M. A1 - Karp-Boss,Lee A1 - Choi,Chang Jae A1 - Worden,Alexandra Z. A1 - Graff,Jason R. A1 - Haentjens,Nils A1 - Chase,Alison P. A1 - Della Penna,Alice A1 - Gaube,Peter A1 - Morison,Francoise A1 - Menden-Deuer,Susanne A1 - Westberry,Toby K. A1 - O'Malley,Robert T. A1 - Boss,Emmanuel A1 - Behrenfeld,Michael J. A1 - Giovannoni,Stephen J. AD - Oregon State Univ, Dept Microbiol, Corvallis, OR 97331 USA. AD - Univ Maine, Sch Marine Sci, Orono, ME USA. AD - Monterey Bay Aquarium Res Inst, Monterey, CA USA. AD - GEOMAR Helmholtz Ctr Ocean Res, Ocean EcoSyst Biol Unit, Kiel, Germany. AD - Oregon State Univ, Dept Bot & Plant Pathol, Corvallis, OR 97331 USA. AD - Univ Washington, Appl Phys Lab, Seattle, WA 98105 USA. AD - Inst Univ Europeen Mer, Lab Sci Environm Marin, Plouzane, France. AD - Univ Rhode Isl, Grad Sch Oceanog, Narragansett, RI 02882 USA. UR - https://archimer.ifremer.fr/doc/00695/80744/ DO - 10.1038/s41396-020-0636-0 N2 - The North Atlantic phytoplankton spring bloom is the pinnacle in an annual cycle that is driven by physical, chemical, and biological seasonality. Despite its important contributions to the global carbon cycle, transitions in plankton community composition between the winter and spring have been scarcely examined in the North Atlantic. Phytoplankton composition in early winter was compared with latitudinal transects that captured the subsequent spring bloom climax. Amplicon sequence variants (ASVs), imaging flow cytometry, and flow-cytometry provided a synoptic view of phytoplankton diversity. Phytoplankton communities were not uniform across the sites studied, but rather mapped with apparent fidelity onto subpolar- and subtropical-influenced water masses of the North Atlantic. At most stations, cells < 20-mu m diameter were the main contributors to phytoplankton biomass. Winter phytoplankton communities were dominated by cyanobacteria and pico-phytoeukaryotes. These transitioned to more diverse and dynamic spring communities in which pico- and nano-phytoeukaryotes, including many prasinophyte algae, dominated. Diatoms, which are often assumed to be the dominant phytoplankton in blooms, were contributors but not the major component of biomass. We show that diverse, small phytoplankton taxa are unexpectedly common in the western North Atlantic and that regional influences play a large role in modulating community transitions during the seasonal progression of blooms. Y1 - 2020/07 PB - Nature Publishing Group JF - Isme Journal SN - 1751-7362 VL - 14 IS - 7 SP - 1663 EP - 1674 ID - 80744 ER -