Biogeosciences, 15, 4923–4942, 2018 https://doi.org/10.5194/bg-15-4923-2018 © Author(s) 2018. This work is distributed under the Creative Commons Attribution 4.0 License. Colony formation in Phaeocystis antarctica: connecting molecular mechanisms with iron biogeochemistry Sara J. Bender1,a, Dawn M. Moran1, Matthew R. McIlvin1, Hong Zheng2, John P. McCrow2, Jonathan Badger2,b, Giacomo R. DiTullio4, Andrew E. Allen2,3, and Mak A. Saito1 1Marine Chemistry and Geochemistry Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, USA 2Microbial and Environmental Genomics, J. Craig Venter Institute, La Jolla, California 92037, USA 3Integrative Oceanography Division, Scripps Institution of Oceanography, UC San Diego, La Jolla, California 92037, USA 4College of Charleston, Charleston South Carolina 29412, USA acurrent address: Gordon and Betty Moore Foundation, Palo Alto, California 94304, USA bcurrent address: Center for Cancer Research, Bethesda, Maryland 20892, USA Correspondence: Mak A. Saito (
[email protected]) Received: 2 January 2018 – Discussion started: 26 January 2018 Revised: 21 July 2018 – Accepted: 26 July 2018 – Published: 21 August 2018 Abstract. Phaeocystis antarctica is an important phyto- high iron (and coincident flagellate or the colonial cell types plankter of the Ross Sea where it dominates the early sea- in strain 1871), implying that there may be specific iron ac- son bloom after sea ice retreat and is a major contribu- quisition systems for each life cycle type. The proteome anal- tor to carbon export. The factors that influence Phaeocys- ysis also revealed numerous structural proteins associated tis colony formation and the resultant Ross Sea bloom ini- with each cell type: within flagellate cells actin and tubulin tiation have been of great scientific interest, yet there is lit- from flagella and haptonema structures as well as a suite of tle known about the underlying mechanisms responsible for calcium-binding proteins with EF domains were observed.