Impacts of unusually light sea-ice cover in winter 2017-2018 on the northern Bering Sea marine ecosystem - An introduction

This paper serves as an introduction to the Deep-Sea Research II special issue on the impacts of a severe lack of sea ice in the northern Bering Sea (NBS) in the winter of 2017-2018. To complement the papers in this volume, we provide a brief synopsis of the physical oceanography of the NBS, including information on the characteristics of the dominant water masses, and the patterns of sea-ice formation and duration in years past. The 17 papers in this volume provide a series of snapshots of the northern Bering Sea in the spring and summer of 2018, which followed an unusual warming in February 2018 and record-breaking low sea-ice concentrations. The lack of ice in spring affected the temperatures and structure of the water column, impacted the timing of the spring bloom, and affected the marine food webs from the amounts and kinds of phytoplankton and zooplankton, to the distribution of fish and the reproduction and survival of marine birds and mammals. As the Arctic and sub-Arctic warm, events like those observed in 2018 may well become the norm. If so, we may anticipate major changes in the NBS marine ecosystem and those dependent upon its resources.