Arctic warming interrupts the Transpolar Drift and affects long-range transport of sea ice and ice-rafted matter

Thomas Krumpen,Ellen Damm,Stephan Paul,Marcel Nicolaus,Rüdiger Stein,Stefan Hendricks,Robert Ricker,Eva-Maria Nöthig,Christian Haas,Ilka Peeken,Antje Boetius,H Jakob Belter

doi:10.1038/s41598-019-41456-y

Abstract

Sea ice is an important transport vehicle for gaseous, dissolved and particulate matter in the Arctic Ocean. Due to the recently observed acceleration in sea ice drift, it has been assumed that more matter is advected by the Transpolar Drift from shallow shelf waters to the central Arctic Ocean and beyond. However, this study provides first evidence that intensified melt in the marginal zones of the Arctic Ocean interrupts the transarctic conveyor belt and has led to a reduction of the survival rates of sea ice exported from the shallow Siberian shelves (−15% per decade). As a consequence, less and less ice formed in shallow water areas (<30 m) has reached Fram Strait (−17% per decade), and more ice and ice-rafted material is released in the northern Laptev Sea and central Arctic Ocean. Decreasing survival rates of first-year ice are visible all along the Russian shelves, but significant only in the Kara Sea, East Siberian Sea and western Laptev Sea. Identified changes affect biogeochemical fluxes and ecological processes in the central Arctic: A reduced long-range transport of sea ice alters transport and redistribution of climate relevant gases, and increases accumulation of sediments and contaminates in the central Arctic Ocean, with consequences for primary production, and the biodiversity of the Arctic Ocean.

Highlights

Predicted future changes towards a seasonally ice-free ocean[13,14] will, at some point, cut-off long-range transport of ice-rafted materials by the Transpolar Drift
Siberian Shelf Seas to the central Arctic Ocean and Fram Strait (Fig. 1c).[18] expect that continued fall and winter ice production coupled with higher ice velocities are likely to ensure continuity of the long-range transport
The analysis of 20 years (1998–2017) of backward trajectories starting in Fram Strait reveals that less and less ice formed in shallow water areas (

Summary

Introduction

Predicted future changes towards a seasonally ice-free ocean[13,14] will, at some point, cut-off long-range transport of ice-rafted materials by the Transpolar Drift. Studies examining long-range transport of sea ice over the past decades are scarce, and the few existing investigations rather indicate an increase in exchange of ice-rafted material between regions. During the past few years, summer ice extent in the marginal ice zones was low, so that most ice exported from the shelves had melted before it could be included in the Transpolar Drift (Fig. 1d). In this study we investigate if intensified summer melt in marginal ice zones is strong enough to cut-off transport pathways much earlier than expected, despite faster drift velocities. We identify potential sites of melt out and intensified release of ice-rafted substances and discuss consequences for the sedimentary budgets, biogeochemical cycle and the ecosystem

Methods

Results

Conclusion