AUTHOR=Mayers Kyle M. J. , Poulton Alex J. , Bidle Kay , Thamatrakoln Kimberlee , Schieler Brittany , Giering Sarah L. C. , Wells Seona R. , Tarran Glen A. , Mayor Dan , Johnson Matthew , Riebesell Ulf , Larsen Aud , Vardi Assaf , Harvey Elizabeth L. 

TITLE=The Possession of Coccoliths Fails to Deter Microzooplankton Grazers

JOURNAL=Frontiers in Marine Science

VOLUME=7

YEAR=2020

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2020.569896

DOI=10.3389/fmars.2020.569896

ISSN=2296-7745

ABSTRACT=<p>Phytoplankton play a central role in the regulation of global carbon and nutrient cycles, forming the basis of the marine food webs. A group of biogeochemically important phytoplankton, the coccolithophores, produce calcium carbonate scales that have been hypothesized to deter or reduce grazing by microzooplankton. Here, a meta-analysis of mesocosm-based experiments demonstrates that calcification of the cosmopolitan coccolithophore, <italic>Emiliania huxleyi</italic>, fails to deter microzooplankton grazing. The median grazing to growth ratio for <italic>E. huxleyi</italic> (0.56 ± 0.40) was not significantly different among non-calcified nano- or picoeukaryotes (0.71 ± 0.31 and 0.55 ± 0.34, respectively). Additionally, the environmental concentration of <italic>E. huxleyi</italic> did not drive preferential grazing of non-calcified groups. These results strongly suggest that the possession of coccoliths does not provide <italic>E. huxleyi</italic> effective protection from microzooplankton grazing. Such indiscriminate consumption has implications for the dissolution and fate of CaCO<sub>3</sub> in the ocean, and the evolution of coccoliths.</p>