The marine ecosystem off southeast Greenland may have passed a significant tipping point and entered a new regime, according to a study published on Monday.
“The disappearance of drift ice may represent a regime transition through a tipping point with cascading consequences for the local ecosystem, including a change in biodiversity and ecosystem functioning,” the study said in the journal Global Change Biology.
“The observed changes in the SEG could therefore be a precursor to the ecological events expected if another, larger tipping element, the summer ice of the Arctic Ocean disappear in the decades to come.
Regime change is not only something we desire in some countries, but it is also a change in ecological conditions driven by physical force. Discover how long-range climatic conditions alter the ecology of the waters of southeast Greenland. https://t.co/KsXa2lJe3T ￼ pic.twitter.com/BMUpxZgqho
— Mads Peter Heide-Jørgensen (@mads_heide) November 21, 2022
“Regime change is not only something we desire in some countries, but it is also a change in ecological conditions driven by physical force,” tweeted Mads Peter Heide-Jørgensen, the lead author of the study.
Changing ice conditions, changing ecosystem
Drifting ice and fast ice have long isolated this area of Greenland and have been an obstacle to exploration of the region and prevented whalers from following the animals to shore, researchers say.
But the low temperatures and extensive sea ice that have marked this region’s habit are changing as the climate warms, the scientists said.
“Conditions that were previously dominant (extensive summer drift ice and low temperatures) are now rare, suggesting that a tipping point involving summer ice cover has been passed and a new state with open water in summer has been reached,” the study said.
Among the changes observed is an increase in the number of killer whales in the area.
Between 1942 and 1984, eight killer whale sightings were recorded in the Tasiilaq area, a Greenlandic community that today numbers around 2,000 people. Between 1950 and 1986, three captures were recorded.
This is in stark contrast to the Period 2003-2018 where at least 77 killer whales were captured, according to the study.
Species expanding their range
The study also highlighted the increased presence of fin whales in the area.
“A large number of fin whales were unexpectedly found in East Greenland coastal waters (less than 50 km from shore) in August 2015; a fully corrected abundance estimate showed there were 6,440 fin whales in the region, although there is little to no historical evidence of fin whales in coastal waters off eastern Greenland,” the researchers said.
Fin whales are one of many different predators and predators that are increasingly present in the region.
“Several large, mobile predator species are expanding their ranges into new habitats,” the study says. “The presence of these species likely has direct and indirect effects on other species in the community and on biodiversity-food web function relationships. Many of these species occupy high levels in the food web and their consumption will likely impact prey and have cascading effects on lower trophic levels of food webs.
At the same time, the number of ice-dependent or cold-tolerant species will decrease as ice conditions decrease.
The narwhal is just one example, according to the study.
“There is evidence that narwhals have a narrow temperature niche of 0.3-1.3°C where most of their diving and foraging activities take place,” the researchers said. “Only areas dominated by the [East Greenland Current} seem to be suitable habitat for narwhals and areas with influx of dense and warm Atlantic water masses seem unsuitable, which will likely lead to a substantial habitat loss for such populations due to climate change.
“The observed changes in [Southeastern Greenland] demonstrate that a regime shift has occurred and will likely be the first signal of what will become an increasingly common scenario in the Arctic.
The study was conducted by the Greenland Institute of Natural Resources.
Write to Eilís at [email protected]
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United States: Bering Sea ice at lowest in at least 5,500 years, study finds, Alaska Public Media