Award: OCE-RIG-1323319

Marine phytoplankton are microscopic photosynthetic organisms that live in the surface ocean and are responsible for approximately half of all photosynthesis on the planet. Phytoplankton also play a critical role in the global carbon cycle through the ?biological pump?, which transfers organic carbon from the surface to the deep ocean acting to remove carbon dioxide from the atmosphere on time-scales of hundreds to millions of years. The strength of the biological pump (how efficient it is at sequestering carbon from the atmosphere) is determined by the interactions between ocean physics, chemistry and biology. The type of phytoplankton (community composition) and their growth rate also has a large impact on the biological pump. Therefore, understanding how phytoplankton respond to variability in their physical and chemical environment, and how this might change as the climate changes, is necessary to not only improve predictions of future ecosystem states but also to better constrain future climate states. Marine phytoplankton live in an environment that is in constant motion such that the physical (e.g. temperature and light) and chemical (e.g. nutrient) environment experienced by these microorganisms is constantly changing. The physical dynamics that impact the surface ocean environment range from large-scale dynamics such as seasonal cycles to finer-scale ?weather events?. While much progress has been made toward understanding the biological impact of large-scale physical dynamics, we have only a limited understanding of how finer-scale physical dynamics impact organisms in the oceans. This is because these fine-scale features are difficult to observe and model. One class of fine-scale ?weather events? in the ocean are submesoscale features. These dynamics are relatively short lived (~several days) and small in size (1-10km) but can drastically alter the physical and chemical environment experienced by phytoplankton. This has the potential to significantly change the growth rates of phytoplankton by creating an environment more favorable for growth, which in turn can increase the efficiency of the biological pump. This project investigated the impact of submesoscale physical dynamics on phytoplankton community composition and carbon cycling in the vast nutrient-limited (oligotrophic) regions of the oceans. Computer models are powerful tools for exploring interactions in complex systems. However, even the most powerful supercomputers are unable to represent the impact of submesoscale physical dynamics on global carbon cycling using conventional modeling approaches. We developed a novel ocean ecosystem model that represents fine-scale interactions between biology and physics using a framework that is computationally inexpensive enough to allow for it to be used in global models. We showed that submesoscale physical dynamics can significantly alter phytoplankton abundance and the cycling of carbon and nitrogen. We validated the model results using high-resolution data from multiple sources including satellite data and measurements made in the surface ocean using automated sampling technologies. Using our new modeling approach, we showed that the time scale (i.e. duration) and the intensity (i.e. magnitude) of the physical dynamics were critical for determining the response of phytoplankton. In addition, changes in the type of submesoscale dynamic could significantly impact marine carbon cycling in the future. This work suggests that fine-scale dynamics such as submesoscale features have the potential to contribute significantly to long term climate-driven changes in the biological pump. While we have come a long way in the fields of science, technology, engineering, and mathematics (STEM), there is still a paucity of women and minorities in both tenure-track faculty positions and in upper level non-academic scientist positions. This is particularly true in the mathematically based fields such as numerical modeling. Through this project, we have actively worked to bring Oceanography to under-represented minorities and underserved communities hoping to start to break the stereotypes of ?what a scientist looks like?, an essential first step in motivating underprivileged and under-represented minority students to explore the STEM fields. Specifically, we visited several K-12 classrooms to showcase the research being done on this project and brought ~70 K-12 students on a day trip to the Wrigley Institute for Environmental Studies on Catalina Island. On the island, we toured the marine lab, taught a lesson on ocean acidification, and completed an ocean acidification lab experiment with the students. For nearly all of the students, this was their first time on a boat and the first time in a research laboratory. Research has shown that providing students exposure to research science early on in their careers increases retention in the STEM fields. This project has also supported research experience and mentoring for high-schoolers, undergraduates, and graduate students from under-represented groups. Last Modified: 10/31/2017 Submitted by: Naomi M Levine