[A-OS12] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

[AOS12-02] Marine biodiversity refugia in the Eastern Bering Sea

★Invited Papers

*Irene Alabia¹, Jorge Molinos¹, Takafumi Hirata¹, Franz Mueter², Toru Hirawake¹, Sei-Ichi Saitoh¹ (1.Hokkaido University, 2.University of Alaska Fairbanks)

Keywords:biodiversity refugia, alpha diversity, temporal beta diversity, Eastern Bering Sea, Pacific Arctic region, sea ice

Pronounced warming and dramatic sea ice loss in the Pacific Arctic are altering marine communities and restructuring biodiversity in the region. Nonetheless, our analyses were able to identify potential refuges of marine biodiversity on the Eastern Bering Sea (EBS) shelf. Here, we examined alpha and temporal beta-diversity patterns of 159 marine taxa from the NOAA bottom trawl surveys in the EBS between 1990 and 2018. Based on these data, we have identified geographically distinct refugial zones in the northern and southern sectors of the middle shelf, shown to have high species richness and similarity in community species composition over time. These features showed higher frequencies of occurrence for representative taxa relative to the regions outside of refugia. We also explored the key environmental factors structuring marine biodiversity distributions, underpinning the importance of the winter sea ice concentration to alpha and temporal beta diversity. Spatial biodiversity distributions between high and low winter sea ice regimes captured a higher species richness in the latter compared to the former. Further, the temporal beta diversity between high and low winter sea ice periods suggested an overall increase in the compositional similarity of marine communities in the EBS. Our findings raised the significance of and advocated the need to identify and manage marine biodiversity refugia to maintain climate-resilient marine ecosystems and fisheries.