Climate-induced long-term variations of the Arctic ecosystems

The Arctic is significantly affected by global climate change where the warming trend is twice as fast as the world, and climate variability pattern such as Arctic Oscillation is active with great ecological effects. Most of the previous pioneering studies focused on a single local ecosystem in the Arctic, however, the similarities and differences in the dynamics of the Arctic ecosystems have been poorly understood in a changing climate. In this study, long-term variations and regime shifts of eight large marine ecosystems (LMEs) around the Arctic were explored with focuses on comparison among ecosystems in the Atlantic and Pacific sector of the Arctic ocean, and on the impacts of climate change and variability. Results of Bayesian Dynamic Factor Analysis indicate that the long-term variations of fish abundance in the most of LMEs in Atlantic sector showed an increasing trend before the 1970s/1980s and decreased subsequently, which representing variations of warm-affinity species, with regime shifts mainly observed in the 1970s. While the LMEs in Pacific sector showed an increasing trend before the 1990s, which representing the increase of most of the warm-affinity species with regimes shifts concentrating in the 1970s. Most of the LMEs were found to be regulated by Atlantic Multi-decadal Oscillation, only the Greenland Sea and West Bering Sea LMEs were related to the sea ice concentration and Pacific Decadal Oscil-lation, respectively. This study can promote understandings on climate-induced variability in Arctic ecosystems at a holistic perspective.