Arctic | Lower Trophic Levels
Predicting epibenthic functional distribution on changing Arctic shelves Presenter: Lauren Sutton , lsutton7@alaska.edu Katrin Iken , kbiken@alaska.edu, University of Alaska - Fairbanks Claudine Hauri , chauri@alaska.edu
Franz Mueter , fmueter@alaska.edu, UAF Remi Pages , rpages@alaska.edu, IARC
Increasingly strong ocean changes influence all marine ecosystems, but especially so in the Pacific Arctic, where climate changes occur two to four times faster than elsewhere. These oceanographic changes will affect the suitability of Arctic marine habitats for current resident species. Understanding habitat suitability and its changes is an essential part of predicting and adapting to changes in ecosystem functioning. Here, we employed a functional traits approach for Arctic epibenthic communities to use trait-environment relationships from historical data to predict future habitat suitability. We used the Northern Bering and Chukchi Sea shelves as example systems where the historically cold, stable, and relatively undisturbed benthic habitats may be changing due to oceanographic changes, resulting in an increasing poleward migration of benthic boreal taxa. We first investigated how benthic communities have changed in the past decade (2009-2019) using regional mean bottom salinities and temperatures for ice-free periods from the hindcast Pan-Arctic Regional Ocean Model System (PAROMS). To predict future changes in functional composition by the middle and end of the century, we used predicted regional mean bottom salinities and temperatures based on the high-carbon emission, low mitigation effort (i.e., “worst case scenario”). Regions in the Northern Bering Sea exhibited functional changes longitudinally in a coastal to offshore direction, while the offshore Northern Chukchi Sea region had a clear south to north change in functional composition over time. These patterns followed past and predicted shifts in hydrographic conditions for these Arctic inflow shelves (i.e., generally increased temperatures and decreased salinities). Prominent shifts in functional composition occurred between the beginning and end of the study period for the most northern region, mostly driven by the functional traits of movement and skeleton, with little change in the middle of the study period. In the most southern region, prominent changes occurred during the end-of-century timeframes, mostly driven by a combination of body size, larval development, and movement. The relatively small changes in functional composition between the recent decade and the projected mid-century period area suggest that the current Arctic epibenthos may have already undergone a larger functional transformation in response to changes in the environment than those expected in the near future.
Alaska Marine Science Symposium 2023 68
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