Collaborative Research: Formation and Persistence of Benthic Biological Hotspots in the Pacific Arctic

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Persistently high macrofaunal benthic biomass has been observed at four major benthic hotspots in the Northern Bering and Chukchi Seas. These highly productive benthic communities are ecologically important and provide abundant prey for benthic-feeding marine mammals and seabirds. This grant supports the exploration of the physical and biological processes that contribute to the formation of these benthic hotspots, and a determination of how changes in the Arctic system (including ice, ocean, and atmospheric forcing) will affect their formation and persistence. A better understanding of the mechanisms for the formation and persistence of these benthic hotspots is important and requires the atmosphere-ice-ocean system approach taken in this study, since these formation mechanisms involve multiple components of the Arctic system, including both biological and physical components of sea ice and ocean processes and atmospheric forcing. The group will integrate a suite of models, including an ice-ocean-ecosystem coupled model and a Lagrangian particle-tracking model, to evaluate source, transport pathway, and supply of organic matter to the benthic community. The modeling will span the entire system from atmospheric forcing down to particle export flux. Explicitly modeling benthic-pelagic coupling is needed for a mechanistic understanding of the ecosystem structure in the Pacific Arctic region and will provide baseline information to better predict future ecosystem shifts. Once the model validation and synthesis with observations are accomplished, the project will have a broad-scale description of the existing and potential locations of benthic hotspots and carbon sources for benthic hotspots across the entire northern Bering and Chukchi Seas, including regions that are presently under-sampled, and their vulnerabilities to ongoing climate and environmental changes. It will also have a better understanding of the mechanisms contributing to benthic hotspot formation (e.g., zooplankton grazing, seasonal and inter-annual variability in advected inputs of production and/or nutrients, role of currents, convergences, turbulence, and particle aggregation in hotspot formation, timing of sea ice formation, cover, and retreat, inter-annual or long-term differences in atmospheric forcing). Both can contribute to the design of future field efforts, since the comprehensive spatial distribution of hotspot location can guide place-based field efforts and the relative importance of modeled ecosystem processes and transformations will inform needs for process studies and distributional studies. With ongoing climate change, atmospheric forcing and ocean currents are likely to change in strength and direction, potentially modifying the locations where the convergence of these mechanisms promotes enhanced carbon export and benthic hotspot formation. Understanding of how these linked mechanisms operate to produce the existing benthic hotspots will permit us to predict empirically their future persistence or relocation. The results of the modeling effort can be used both by the scientific community in guiding future fieldwork and modeling efforts and more broadly by managers and policy makers in guiding the development and implementation of management and commercial strategies and guidelines. This work will include outreach activities primarily focused on K-12 education, focusing on the importance of atmospheric forcing, sea ice, currents, and benthic-pelagic coupling to the Bering/Chukchi Sea system and the impacts of ongoing climate change on that system.