Program     Pushing the frontiers of marine ecological modeling: where are we now and how can we move forward?       0930 Small but mighty - the role that marine microbes play in mediating our climate  (Invited) Monday 7th @ 0930-0950, Conference Room 5 Naomi M Levine* , University of Southern California Elizabeth Teel, University of Southern California Meagan He, University of Southern California Emily Zakem, University of Southern California Presenter Email: n.levine@usc.edu Microscopic single celled organisms in the ocean (marine microbes) are the engines that drive marine carbon cycling. They are responsible for approximately half of all photosynthesis on the planet and play a critical role in in regulating our climate by mediating the sequestration of CO2 in the ocean. As such, it is important to determine how marine microbes will adapt and evolve to a changing climate in order to understand and predict how the global carbon cycle may change, and predict pivotal feedback responses that might impact future climate states. To untangling the complex interactions between climate and biology, we utilize pioneering interdisciplinary approaches combining observations, theory, and numerical models. This research demonstrates that the inclusion of dynamic bacterial remineralization can significantly impact surface phytoplankton blooms, and picophytoplankton primary production rates. Model dynamics also indicated that variable C:N ratios are critical for the depiction of both DOC production and remineralization. In addition, this work suggests that explicitly including heterotrophic bacterial dynamics in global ecosystem models may be important for accurately representing carbon cycle responses to climate perturbations.

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