Details of the Researcher

PHOTO

Casey John Rossiter
Section
Advanced Institute for Marine Ecosystem Change
Job title
Associate Professor

Research History 5

  • 2025/12 - Present
    Tohoku University　Advanced Institute for Marine Ecosystem Change　Associate Professor

  • 2022/09 - 2025/09
    Lawrence Livermore National Laboratory　Physical and Life Sciences　Postdoctoral Researcher

  • 2019/05 - 2022/09
    Massachusetts Institute of Technology　Department of Earth, Atmospheric and Planetary Sciences　Postdoctoral Researcher

  • 2017/07 - 2019/05
    University of Hawaii at Manoa　School of Ocean and Earth Science and Technology　Postdoctoral Researcher

  • 2007/05 - 2010/07
    Bermuda Institute of Ocean Sciences　Marine Phytoplankton Ecology Laboratory　Research Technician

Education 1

  • University of Hawaii at Manoa　Department of Oceanography　Ph.D.

    2010/09 - 2017/05

Committee Memberships 1

  • SRI International　CyanoCyc

    2022/06 - Present

Research Interests 4

  • Reinforcement Learning

  • Ecosystem Modeling

  • Metabolic Modeling

  • Microbial Oceanography

Research Areas 1

  • Life sciences / Marine/Aquatic life sciences / Microbial Oceanography

Papers 26

  1. Spatially structured bacterial interactions alter algal carbon flow to bacteria

    Hyungseok Kim, Vanessa L Brisson, John R Casey, Courtney Swink, Kristina A Rolison, Nathan McCall, Amber N Golini, Trent R Northen, Dušan Veličković, Peter K Weber, Cullen R Buie, Xavier Mayali, Rhona K Stuart

    The ISME Journal　2025/01/02

    DOI： 10.1093/ismejo/wraf096 　

    ISSN： 1751-7362 1751-7370

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    <jats:title>Abstract</jats:title> <jats:p>Phytoplankton account for nearly half of global photosynthetic carbon fixation, and the fate of that carbon is regulated in large part by microbial food web processing. We currently lack a mechanistic understanding of how interactions among heterotrophic bacteria impact the fate of photosynthetically fixed carbon. Here, we used a set of bacterial isolates capable of growing on exudates from the diatom Phaeodactylum tricornutum to investigate how bacteria-bacteria interactions affect the balance between exudate remineralization and incorporation into biomass. With exometabolomics and genome-scale metabolic modeling, we estimated the degree of resource competition between bacterial pairs. In a sequential spent media experiment, we found that pairwise interactions were more beneficial than predicted based on resource competition alone, and 30% exhibited facilitative interactions. To link this to carbon fate, we used single-cell isotope tracing in a custom cultivation system to compare the impact of different “primary” bacterial strains in close proximity to live P. tricornutum on a distal “secondary” strain. We found that a primary strain with a high degree of competition decreased secondary strain carbon drawdown by 51% at the single-cell level, providing a quantitative metric for the “cost” of competition on algal carbon fate. Additionally, a primary strain classified as facilitative based on sequential interactions increased total algal-derived carbon assimilation by 7.6 times, integrated over all members, compared to the competitive primary strain. Our findings suggest that the degree of interaction between bacteria along a spectrum from competitive to facilitative is directly linked to algal carbon drawdown.</jats:p>

  2. Transporter annotations are holding up progress in metabolic modeling

    John Casey, Brian Bennion, Patrik D’haeseleer, Jeffrey Kimbrel, Gianna Marschmann, Ali Navid

    Frontiers in Systems Biology　2024/07/24

    DOI： 10.3389/fsysb.2024.1394084 　

    ISSN： 2674-0702

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    <jats:p>Mechanistic, constraint-based models of microbial isolates or communities are a staple in the metabolic analysis toolbox, but predictions about microbe-microbe and microbe-environment interactions are only as good as the accuracy of transporter annotations. A number of hurdles stand in the way of comprehensive functional assignments for membrane transporters. These include general or non-specific substrate assignments, ambiguity in the localization, directionality and reversibility of a transporter, and the many-to-many mapping of substrates, transporters and genes. In this perspective, we summarize progress in both experimental and computational approaches used to determine the function of transporters and consider paths forward that integrate both. Investment in accurate, high-throughput functional characterization is needed to train the next-generation of predictive tools toward genome-scale metabolic network reconstructions that better predict phenotypes and interactions. More reliable predictions in this domain will benefit fields ranging from personalized medicine to metabolic engineering to microbial ecology.</jats:p>

  3. CyanoCyc cyanobacterial web portal

    Moore, L.R., Caspi, R., Campbell, D.A., Casey, J.R., Crevecoeur, S., Lea-Smith, D.J., Long, B., Omar, N.M., Paley, S.M., Schmelling, N.M., Torrado, A., Zehr, J.P., Karp, P.D.

    Frontiers in Microbiology　15　2024

    DOI： 10.3389/fmicb.2024.1340413 　

    ISSN： 1664-302X

  4. Disentangling top-down drivers of mortality underlying diel population dynamics of Prochlorococcus in the North Pacific Subtropical Gyre

    Beckett, S.J., Demory, D., Coenen, A.R., Casey, J.R., Dugenne, M., Follett, C.L., Connell, P., Carlson, M.C.G., Hu, S.K., Wilson, S.T., Muratore, D., Rodriguez-Gonzalez, R.A., Peng, S., Becker, K.W., Mende, D.R., Armbrust, E.V., Caron, D.A., Lindell, D., White, A.E., Ribalet, F., Weitz, J.S.

    Nature Communications　15　(1)　2024

    DOI： 10.1038/s41467-024-46165-3 　

    ISSN： 2041-1723

  5. Determining drivers of phytoplankton carbon to chlorophyll ratio at Atlantic Basin scale

    Smyth, T., Moffat, D., Tarran, G., Sathyendranath, S., Ribalet, F., Casey, J.

    Frontiers in Marine Science　10　2023

    DOI： 10.3389/fmars.2023.1191216 　

    ISSN： 2296-7745

  6. Basin-scale biogeography of marine phytoplankton reflects cellular-scale optimization of metabolism and physiology

    John R. Casey, Rene M. Boiteau, Martin K. M. Engqvist, Zoe V. Finkel, Gang Li, Justin Liefer, Christian L. Müller, Nathalie Muñoz, Michael J. Follows

    Science Advances　8　(3)　2022/01/21

    Publisher: American Association for the Advancement of Science ({AAAS})

    DOI： 10.1126/sciadv.abl4930 　

  7. Complex marine microbial communities partition metabolism of scarce resources over the diel cycle

    Daniel Muratore, Angela K. Boysen, Matthew J. Harke, Kevin W. Becker, John R. Casey, Sacha N. Coesel, Daniel R. Mende, Samuel T. Wilson, Frank O. Aylward, John M. Eppley, Alice Vislova, Shengyun Peng, Rogelio A. Rodriguez-Gonzalez, Stephen J. Beckett, E. Virginia Armbrust, Edward F. DeLong, David M. Karl, Angelicque E. White, Jonathan P. Zehr, Benjamin A. S. Van Mooy, Sonya T. Dyhrman, Anitra E. Ingalls, Joshua S. Weitz

    Nature Ecology & Evolution　2022/01/20

    DOI： 10.1038/s41559-021-01606-w 　

  8. A Bayesian approach to modeling phytoplankton population dynamics from size distribution time series

    Jann Paul Mattern, Kristof Glauninger, Gregory L. Britten, John R. Casey, Sangwon Hyun, Zhen Wu, E. Virginia Armbrust, Zaid Harchaoui, François Ribalet

    PLOS Computational Biology　18　(1)　2022/01/14

    Publisher: Public Library of Science ({PLoS})

    DOI： 10.1371/journal.pcbi.1009733 　

  9. Disentangling top-down drivers of mortality underlying diel population dynamics ofProchlorococcusin the North Pacific Subtropical Gyre

    Stephen J. Beckett, David Demory, Ashley R. Coenen, John R. Casey, Mathilde Dugenne, Christopher L. Follett, Paige Connell, Michael C.G. Carlson, Sarah K. Hu, Samuel T. Wilson, Daniel Muratore, Rogelio A. Rodriguez-Gonzalez, Shengyun Peng, Kevin W. Becker, Daniel R. Mende, E. Virginia Armbrust, David A. Caron, Debbie Lindell, Angelicque E. White, François Ribalet, Joshua S. Weitz

    2021/06/16

    DOI： 10.1101/2021.06.15.448546 　

  10. A steady-state model of microbial acclimation to substrate limitation

    John R. Casey, Michael J. Follows

    PLOS Computational Biology　16　(8)　2020/08/26

    Publisher: Public Library of Science ({PLoS})

    DOI： 10.1371/journal.pcbi.1008140 　

  11. Community-scale Synchronization and Temporal Partitioning of Gene Expression, Metabolism, and Lipid Biosynthesis in Oligotrophic Ocean Surface Waters

    Daniel Muratore, Angie K. Boysen, Matthew J. Harke, Kevin W. Becker, John R. Casey, Sacha N. Coesel, Daniel R. Mende, Samuel T. Wilson, Frank O. Aylward, John M. Eppley, Alice Vislova, Shengyun Peng, Rogelio A. Rodriguez-Gonzalez, Stephen J. Beckett, E. Virginia Armbrust, Edward F. DeLong, David M. Karl, Angelicque E. White, Jonathan P. Zehr, Benjamin A.S. Van Mooy, Sonya T. Dyhrman, Anitra E. Ingalls, Joshua S. Weitz

    2020/05/16

    DOI： 10.1101/2020.05.15.098020 　

  12. Kīlauea lava fuels phytoplankton bloom in the North Pacific Ocean

    Samuel T. Wilson, Nicholas J. Hawco, E. Virginia Armbrust, Benedetto Barone, Karin M. Björkman, Angela K. Boysen, Macarena Burgos, Timothy J. Burrell, John R. Casey, Edward F. DeLong, Mathilde Dugenne, Stephanie Dutkiewicz, Sonya T. Dyhrman, Sara Ferrón, Michael J. Follows, Rhea K. Foreman, Carolina P. Funkey, Matthew J. Harke, Britt A. Henke, Christopher N. Hill, Annette M. Hynes, Anitra E. Ingalls, Oliver Jahn, Rachel L. Kelly, Angela N. Knapp, Ricardo M. Letelier, Francois Ribalet, Eric M. Shimabukuro, Ryan K. S. Tabata, Kendra A. Turk-Kubo, Angelicque E. White, Jonathan P. Zehr, Seth John, David M. Karl

    Science　365　(6457)　1040-1044　2019/09/06

    Publisher: American Association for the Advancement of Science ({AAAS})

    DOI： 10.1126/science.aax4767 　

  13. Methylphosphonate Oxidation in Prochlorococcus Strain MIT9301 Supports Phosphate Acquisition, Formate Excretion, and Carbon Assimilation into Purines

    Oscar A. Sosa, John R. Casey, David M. Karl

    Applied and Environmental Microbiology　2019/07

    DOI： 10.1128/AEM.00289-19 　

  14. Size dependence of metabolism within marine picoplankton populations

    John R. Casey, Karin M. Björkman, Sara Ferrón, David M. Karl

    Limnology and Oceanography　2019/07

    DOI： 10.1002/lno.11153 　

  15. Light-Enhanced Microbial Organic Carbon Yield

    John Casey

    Frontiers in Microbiology　2017/11/16

    DOI： 10.3389/fmicb.2017.02157 　

    ISSN： 1664-302X

  16. Coordinated regulation of growth, activity and transcription in natural populations of the unicellular nitrogen-fixing cyanobacterium Crocosphaera

    Wilson, S.T., Aylward, F.O., Ribalet, F., Barone, B., Casey, J.R., Connell, P.E., Eppley, J.M., Ferron, S., Fitzsimmons, J.N., Hayes, C.T., Romano, A.E., Turk-Kubo, K.A., Vislova, A., Virginia Armbrust, E., Caron, D.A., Church, M.J., Zehr, J.P., Karl, D.M., De Long, E.F.

    Nature Microbiology　2　2017

    DOI： 10.1038/nmicrobiol.2017.118 　

    ISSN： 2058-5276

  17. Adaptive Evolution of Phosphorus Metabolism in Prochlorococcus

    John R. Casey, Adil Mardinoglu, Jens Nielsen, David M. Karl

    mSystems　1　(6)　2016/12/27

    Publisher: American Society for Microbiology

    DOI： 10.1128/mSystems.00065-16 　

  18. Draft genome sequence of marine alphaproteobacterial strain HIMB11, the first cultivated representative of a unique lineage within the Roseobacter clade possessing an unusually small genome

    Durham, B.P., Grote, J., Whittaker, K.A., Bender, S.J., Luo, H., Grim, S.L., Brown, J.M., Casey, J.R., Dron, A., Florez-Leiva, L., Krupke, A., Luria, C.M., Mine, A.H., Nigro, O.D., Pather, S., Talarmin, A., Wear, E.K., Weber, T.S., Wilson, J.M., Church, M.J., DeLong, E.F., Karl, D.M., Steward, G.F., Eppley, J.M., Kyrpides, N.C., Schuster, S., Ra, e}, M.

    Standards in Genomic Sciences　9　(3)　2015

    DOI： 10.4056/sigs.4998989 　

  19. Substrate selection for heterotrophic bacterial growth in the sea

    Casey, J.R., Falkowski, P.G., Karl, D.M.

    Marine Chemistry　177　2015

    DOI： 10.1016/j.marchem.2015.06.032 　

  20. Long-term variability of phytoplankton carbon biomass in the Sargasso Sea

    Wallhead, P.J., Gar?on, V.C., Casey, J.R., Lomas, M.

    Global Biogeochemical Cycles　28　2014

    DOI： 10.1002/2013GB004797 　

  21. Changes in partitioning of carbon amongst photosynthetic pico- and nano-plankton groups in the Sargasso Sea in response to changes in the North Atlantic Oscillation

    Casey, J.R., Aucan, J.P., Goldberg, S.R., Lomas, M.

    Deep-Sea Research Part II: Topical Studies in Oceanography　93　2013

    DOI： 10.1016/j.dsr2.2013.02.002 　

  22. Spatial and seasonal variability of primary production on the Eastern Bering Sea shelf

    Lomas, M.W., Moran, S.B., Casey, J.R., Bell, D.W., Tiahlo, M., Whitefield, J., Kelly, R.P., Mathis, J.T., Cokelet, E.D.

    Deep-Sea Research Part II: Topical Studies in Oceanography　65-70　2012

    DOI： 10.1016/j.dsr2.2012.02.010 　

  23. Phytoplankton responses to atmospheric metal deposition in the coastal and open-ocean Sargasso Sea

    Mackey, K.R.M., Buck, K.N., Casey, J.R., Cid, A., Lomas, M.W., Sohrin, Y., Paytan, A.

    Frontiers in Microbiology　3　(OCT)　2012

    DOI： 10.3389/fmicb.2012.00359 　

  24. Assimilation of upwelled nitrate by small eukaryotes in the Sargasso Sea

    Fawcett, S.E., Lomas, M.W., Casey, J.R., Ward, B.B., Sigman, D.M.

    Nature Geoscience　4　(10)　2011

    DOI： 10.1038/ngeo1265 　

  25. Phytoplankton taxon-specific orthophosphate (Pi) and ATP utilization in the western subtropical North Atlantic

    Casey, J.R., Lomas, M.W., Michelou, V.K., Dyhrman, S.T., Orchard, E.D., Ammerman, J.W., Sylvan, J.

    Aquatic Microbial Ecology　58　(1)　2010

    DOI： 10.3354/ame01348 　

  26. Prochlorococcus contributes to new poduction in the Sargasso Sea deep chlorophyll maximum

    Casey, J.R., Lomas, M.W., Mandecki, J., Walker, D.E.

    Geophysical Research Letters　34　(10)　2007

    DOI： 10.1029/2006GL028725 　

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