Mayers Kyle M. J.

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Mayers
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Kyle M. J.
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  • Article
    The possession of coccoliths fails to deter microzooplankton grazers
    (Frontiers Media, 2020-12-02) Mayers, Kyle M. J. ; Poulton, Alex J. ; Bidle, Kay D. ; Thamatrakoln, Kimberlee ; Schieler, Brittany ; Giering, Sarah L. C. ; Wells, Seona R. ; Tarran, Glen A. ; Mayor, Daniel J. ; Johnson, Matthew D. ; Riebesell, Ulf ; Larsen, Aud ; Vardi, Assaf ; Harvey, Elizabeth L.
    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, Emiliania huxleyi, fails to deter microzooplankton grazing. The median grazing to growth ratio for E. huxleyi (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 E. huxleyi did not drive preferential grazing of non-calcified groups. These results strongly suggest that the possession of coccoliths does not provide E. huxleyi effective protection from microzooplankton grazing. Such indiscriminate consumption has implications for the dissolution and fate of CaCO3 in the ocean, and the evolution of coccoliths.
  • Article
    Targeted and untargeted lipidomic analysis of haptophyte cultures reveals novel and divergent nutrient-stress adaptations
    (Elsevier, 2021-11-11) Lowenstein, Daniel P. ; Mayers, Kyle M. J. ; Fredricks, Helen F. ; Van Mooy, Benjamin A. S.
    Lipids comprise a significant, highly plastic proportion of the biomass in haptophytes, a ubiquitous, globally significant, and genetically diverse clade of photosynthetic microalgae. Recent studies have investigated the cellular lipidomes of disparate, individual species of haptophytes under nutrient-replete and nutrient-limited conditions, but have not investigated how lipidomes vary across the larger evolutionary clade or its ecological functional groups. We cultured eight species of haptophytes, including five strains of Emiliania huxleyi, for analysis via high performance liquid chromatography–high resolution accurate mass–mass spectrometry (HPLC–HRAM–MS), and performed untargeted computational and hierarchical cluster analyses on their lipidomes. We identified similarities and differences in lipidomes along both evolutionary and ecological lines, and identified potential biomarkers for haptophyte sub-clades, including 38 glycosphingolipids, seven betaine-like lipids, and three phosphatidyl-S,S-dimethylpropanethiol (PDPT) sulfo-phospholipids. We also provide the first evidence for the glycolipid, glucuronosyldiacylglycerol, in eukaryotic microalgae. We conducted a more targeted study of four haptophyte species under nitrogen- and phosphorus-limited conditions to investigate their lipidomic responses to nutrient stress. Under N- and P-limitation, the species exhibited disparate lipidomic responses. Uniquely, in response to N-limitation, E. huxleyi CCMP 374 heavily upregulated PDPT from 3.6 ± 0.9% to 10.4 ± 1.5% of quantified polar lipids. These previously uncharacterized lipidomes and responses to nutrient limitation reflect divergent evolutionary strategies and challenge popular phenotypic extrapolations between species.