At the rainbow’s end: high productivity fueled by winter upwelling along an Arctic shelf

Stig Falk-Petersen,Jørgen Berge,Vladimir Pavlov,Kit M Kovacs,Finlo Cottier,Christian Lydersen

doi:10.1007/s00300-014-1482-1

Abstract

Herein we document findings from a unique scientific expedition north of Svalbard in the middle of the polar night in January 2012, where we observed an ice edge north of 82°N coupled with pronounced upwelling. The area north of Svalbard has probably been ice-covered during winter in the period from approximately 1790 until the 1980s, a period during which heavy ice conditions have prevailed in the Barents Sea and Svalbard waters. However, recent winters have been characterized by midwinter open water conditions on the shelf, concomitant with northeasterly along-shelf winds in January 2012. The resulting northward Ekman transport resulted in a strong upwelling of Atlantic Water along the shelf. We suggest that a reduction in sea ice and the upwelling of nutrient-rich waters seen in the winter of 2012 created conditions similar to those that occurred during the peak of the European whaling period (1690–1790) and that this combination of physical features was in fact the driving force behind the high primary and secondary production of diatoms and Calanus spp., which sustained the large historical stocks of bowhead whales (Balaena mysticetus) in Arctic waters near Spitsbergen.

Highlights

Vinje’s pioneering work published in 1999 (Vinje 1999) documented the location of the minimum ice edge between Svalbard and Franz Josef Land (20–45°E), based on logbooks from whalers and early explorers that frequented these waters in late summer and autumn
We suggest that a reduction in sea ice and the upwelling of nutrient-rich waters seen in the winter of 2012 created conditions similar to those that
We suggest that similar upwelling events bringing warm, nutrient-rich Atlantic Water to the surface along the shelf north of Svalbard have occurred in the past—leading to high levels of primary production

Summary

Introduction

Vinje’s pioneering work published in 1999 (Vinje 1999) documented the location of the minimum ice edge between Svalbard and Franz Josef Land (20–45°E), based on logbooks from whalers and early explorers that frequented these waters in late summer and autumn. The near extinction of the bowhead whale stock near Svalbard during this time was followed by a period of rapid increase in the extent of summer (August) sea ice commencing around 1790, when the ice edge moved some 500 km southwards to the southern tip of Spitsbergen (around 76°N) within just a few years.

Results

Conclusion