Project: Collaborative Research: Understanding the impact of warming on the structure and function of marine communities

NSF Award Abstract:
Rising temperatures are impacting marine ecosystems around the world, and the rate of warming is expected to accelerate. The ecosystems in the northwest Atlantic Shelf, including in the Gulf of Maine and Mid-Atlantic Bight, have experienced some of the fastest decadal and 30 year warming rates in the historical record, and these strong warming trends were punctuated by marine heatwaves in 2012, 2016, and 2018. Most studies of climate impacts in the ocean have focused on how rising temperatures affect individual species. This project focuses on the impact of warming, both short-term events and long-term trends, on the entire ecosystem. It leverages the region's recent warming and history of consistent sampling to contrast the properties of the plankton and fish communities in the colder Gulf of Maine with the warmer Mid-Atlantic Bight. Through statistical analyses, size-based modeling, and food web modeling, this project evaluates direct and indirect influences of temperature on biological processes, community characteristics, and emergent ecosystem properties. This study characterizes composition and features of the plankton and fish communities and compares ecosystem changes across space and through time. It also isolates the direct influence of temperature on metabolism and growth from the indirect influence of temperature through changes in the oceanography. An understanding how marine ecosystems respond to warming is essential to successfully manage these ecosystems in a changing climate. The project team is actively engaged in translating knowledge into fisheries management at a regional and national level. This project also educates the next generation of citizens and scientists by expanding the ecosystem modeling activity in the Gulf of Maine Research Institute's LabVenture program, which serves ~10,000 Maine middle school students each year. An online curriculum on modeling, a topic area in the Next Generation Science Standards that many teachers find challenging is under development. The project also supports a postdoctoral researcher and a graduate student and contributes to Stony Brook University's program to encourage participation of women in the sciences.

Temperature affects metabolism and growth, with most species growing faster but maturing earlier and at a smaller size in warmer conditions. This project characterizes the direct influence of temperature on fish growth patterns and incorporates this knowledge into a trait-based, size-spectrum model of a fish community. This model quantifies how changes in temperature and zooplankton composition translate into changes in size structure of the fish community. Warming causes poleward movement of species such that traditionally cooler ecosystems come to resemble warmer ecosystems of the past. This project uses a dynamic food-web model to synthesize how changes in species composition have altered the flow of energy in Gulf of Maine and Mid-Atlantic Bight ecosystems. It also quantifies the stability of these communities and their resilience to perturbations like marine heatwaves, with the expectation that gradual warming causes communities to become more diverse and thus more stable, while abrupt warming may have the opposite effect. Both components contrast the ecosystem properties in the warmer mid Atlantic with those in the cooler Gulf of Maine as well as those properties in the past with those under the recent very warm conditions. The comparative approach also untangles the direct impact of warming on organisms from the indirect effects from vertical stratification. In particular, comparing the recent thermally stratified period with the 1990s, when reduced salinity led to an abrupt, multi trophic-level community shift, make it possible to isolate the direct effects of temperature from its influence through hydrography.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.