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A regime shift in Southeast Greenland marine ecosystem

Citation

Heide-Jørgensen, Mads Peter (2022), A regime shift in Southeast Greenland marine ecosystem, Dryad, Dataset, https://doi.org/10.5061/dryad.8sf7m0cs9

Abstract

Two major oceanographic changes have recently propagated through several trophic levels in coastal areas of Southeast Greenland (SEG). Firstly, the amount of drift-ice exported from the Fram Strait and transported with the East Greenland Current (EGC) has decreased significantly over the past two decades, and a main tipping element (summer sea ice) has virtually disappeared since 2003 leading to a regime shift in oceanographic and ecological conditions in the region. The following 20-year period with low or no coastal sea ice is unique in the 200-year history of ice observations in the region, and the regime shift is also obvious in the volume of ice export through the Fram Strait after 2013. In the same period the temperature of the EGC south of 73.5N has increased significantly (>2oC) since 1980. Secondly, the warm Irminger Current, that advects warm, saline Atlantic Water into the region, has become warmer since 1990. The lack of pack ice in summer together with a warming ocean generated cascading effects on the ecosystem in SEG that are manifested in a changed fish fauna with an influx of boreal species in the south and the subarctic capelin further north. At higher trophic levels there has been an increase in the abundance of several boreal cetaceans (humpback, fin, killer and pilot whales and dolphins) that are either new to this area or occur in historically large numbers. It is estimated that the new cetacean species in SEG are responsible for an annual predation level of 700.000 tonnes of fish. In addition, predation on krill species is estimated at >1.500.000 tonnes mainly consumed by the fin whales. Simultaneously there has been a reduction in the abundance and catches of narwhals and walrus in SEG and it is suggested that these species have been impacted by the habitat changes. 

Methods

It is processed data from remote sensing, shore based observation and catch statistics

Usage Notes

Files can be accessed using Excel or R.

Funding

Greenland Institute of Natural Resources, Award: ECOTIP