Arctic | Climate and Oceanography
Climate change impacts on marine light in Arctic ecosystems Presenter: Trond Kristiansen , trondkr@faralloninstitute.org, Farallon Institute for Advanced Ecosystem Research
Øystein Varpe , Oystein.Varpe@uib.no Elizabeth Selig, R. , eselig@stanford.edu
Ben Laurel , ben.laurel@noaa.gov, NOAA Alaska Fisheries Science Center William Sydeman , wsydeman@faralloninstitute.org, Farallon Institute
Michaela Hegglin, I. , m.i.hegglin@reading.ac.uk Kenneth Drinkwater, F. , ken.drinkwater@hi.no Phil Wallhead , philip.wallhead@niva.no
Warming and loss of sea ice will alter light availability across Arctic ecosystems, impacting productivity, phenology, predator-prey interactions, and mortality of key species. In this study, we first quantify how future conditions for sea ice and snow, storm-driven waves, cloud cover, ozone, and chlorophyll content will affect the seasonal absorption and reflection of light in the water column. We then examine how new light and thermal regimes may impact polar cod ( Boreogadus saida ), the most abundant Arctic forage fish species. Using CMIP6 inputs and a simplified radiative transfer model, we find sub-Arctic seas will be transformed by reductions in sea ice and warmer oceans increasing open water and the amount of light reaching into the ocean. In the Barents Sea and Northern Bering and Chukchi ecosystems, we predict a 10-50% increase in visible light coupled with an unanticipated 5-25% decrease in UV-B light by 2100. Such changes will likely benefit boreal fish species with open-water spawning and high summer growth potential. However, we predict polar cod will lose spawning habitat due to winter warming and mis-matched seasonal production of ice-algae and the under-ice-blooms. Overall, we expect climate-driven changes in light to accelerate the re-ordering of sub-Arctic food webs ahead of predictions based on thermal niche models.
Alaska Marine Science Symposium 2023 65
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