[A-OS13] Marine ecosystems and biogeochemical cycles: theory, observation and modeling

[AOS13-04] Future biogeographic shifts of marine biodiversity in the Pacific Arctic

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

Keywords:Biodiversity, climate change, biogeographic transition zones, Pacific arctic, species distribution

Climate change triggers a global reorganization of marine life. Biogeographical transition zones are redistribution hotspots that offer a unique opportunity to understand the mechanisms and consequences of climate-driven thermophilization processes in natural communities. Here, we examined the impacts of climate change projections in the 21^st century (2026-2100) on marine biodiversity in the Eastern Bering and Chukchi seas, a climate-sensitive boreal-to-Arctic transition zone. Overall, projected changes in species distributions, resulted in poleward increases in species richness and functional redundancy, along with pronounced reductions in phylogenetic distances by century’s end (2076-2100). Future poleward shifts of boreal species in response to warming and sea ice changes are projected to alter the biogeography of present-day Arctic communities as larger, longer-lived, and predatory taxa expand their leading distribution margins. Drawing from the existing evidence from other Arctic regions, these changes are anticipated to increase the future vulnerability of Arctic ecosystems, as trophic connectivity between biotic components increases. Our findings provided key insights into relationships between climate change, species composition, and ecosystem functioning across marine biogeographic regions.