The “Atlantification” of the Arctic

May 14, 2018

Codfish and Mackerel migrating from the Atlantic north into the Arctic.

Someone needs to explain to them that there is no global warming, they can all go back where they came from.

Reminder: Deep explainer interviews from Scientists like Dr. Barber happen because of your support for Dark Snow Project.

Yale Environment 360:

Above Scandinavia, on the Atlantic side of the Arctic Ocean, mackerel, cod, and other fish native to the European coast are migrating through increasingly ice-free waters, heading deeper into the Arctic Basin toward Siberia. Thousands of miles to the west, above Alaska, kittiwakes and other polar seabirds are being supplanted by southern birds following warm waters streaming north through the Bering Strait. And midway between, above Canada, sea ice-avoiding killer whales from the Atlantic are increasingly making themselves at home in a thawing Arctic.supportdarksnow

As the Arctic heats up faster than any other region on the planet, once-distinct boundaries between the frigid polar ocean and its warmer, neighboring oceans are beginning to blur, opening the gates to southern waters bearing foreign species, from phytoplankton to whales. The “Atlantification” and “Pacification” of the Arctic Ocean are now rapidly advancing. A new paper by University of Washington oceanographer Rebecca Woodgate, for example, finds that the volume of Pacific Ocean water flowing north into the Arctic Ocean through the Bering Strait surged up to 70 percent over the past decade and now equals 50 times the annual flow of the Mississippi River. And over on the Atlantic flank of the Arctic, another recent report concludes that the Arctic Ocean’s cold layering system that blocks Atlantic inflows is breaking down, allowing a deluge of warmer, denser water to flood into the Arctic Basin.

Because the oceanographic conditions in the Atlantic and Pacific sectors of the Arctic are distinct, the physical mechanisms behind these widespread changes differ. But scientists say that the growing intrusions on both sides of the Arctic Ocean are driving heat, nutrients, and temperate species to new polar latitudes — with profound impacts on Arctic Ocean dynamics, marine food webs, and longstanding predator-prey relationships.

“You’re really changing the system in terms of its capacity for production with the loss of sea ice, influx of nutrients, and also this ‘highway of prey,’” says Sue Moore, a biological oceanographer with the National Oceanic and Atmospheric Administration (NOAA) Fisheries Office of Science and Technology who studies marine ecosystems in the Pacific Arctic. “It’s a whole resetting of the table.”

Striking ecosystem effects are becoming evident across the high north. Some species appear to be gaining new habitat, while others seem to be rapidly losing ground.

On the Pacific side, humpback whales, a sub-Arctic species, have been observed in recent years as far north as Utqiaġvik (formerly called Barrow), off Alaska’s North Slope, where they had not been reported before. Moore thinks the whales are feasting on pulses of Pacific krill and other food streaming into the Arctic. Reduction in sea ice also allows whales to arrive earlier and stay later, giving them more time to feed and reproduce.

And this past winter, when sea ice in the Alaskan Arctic formed up to three months late and disappeared at the earliest date on record, “We had bowhead whales in the Chukchi Sea pretty much overwinter —we have never seen that before now,” says Moore, who is co-leader of the Synthesis of Arctic Research project, an international collaboration of polar experts looking at the effects of a changing Pacific Arctic on marine life.

arcticocean

Along the Arctic coast of western Canada, indigenous fishermen report salmon venturing unusually far north, says Carolina Behe, the indigenous knowledge science advisor for the Inuit Circumpolar Council-Alaska. And scientists conducting an Arctic ecosystem survey in 2008 were surprised to find walleye pollock and Pacific cod in the Beaufort Sea, said Elizabeth Logerwell, an ecologist with the NOAA Alaska Fisheries Science Center who co-led the survey. If these more southern species extend their range north, they could potentially supplant native Arctic fish. She cautioned, however, that the region lacks long-term historical fish survey data, making it hard to know for certain whether these were actually new arrivals or just being scientifically observed for the first time.

Scientists do say that the intrusion of Pacific waters is taking a toll on seabirds in the Alaskan Arctic. Traditional summer denizens in the Chukchi Sea — such as black-legged kittiwakes, thick-billed murres, and glaucous gulls — are now being supplanted by least and crested auklets, northern fulmars, and short-tailed shearwaters, which had not previously ventured so far north. The shift reflects a change in the birds’ prey, with new prey species being swept north through the Bering Strait. The change is causing an overall decline in seabird numbers, a recent paper concludes.

Signs of ecosystem shifts are even more dramatic on the Atlantic side of the Arctic, where Atlantic Ocean inflows overall are far warmer, larger, and saltier. Moore likens the incursion across the long boundary zone above Iceland and Scandinavia to a “firehose,” compared to a “garden hose” on the Pacific side, where incoming waters are constrained by the relatively narrow Bering Strait.

“When I came to Norway in 1974, the northern border for mackerel was western Norway,” says Paul Wassmann, a professor of marine ecology at the Arctic University of Norway in Tromsø and an expert on ice-edge ecosystems. “Now you can see [mackerel] in Svalbard fjords,” he says, referring to a group of Norwegian Arctic islands that lie nearly 600 miles above the mainland as far as 81 degrees North. Buoyed by Atlantic intrusions, warm water species are spreading northeast into the Arctic Ocean, and resident cold–adapted species, such as Arctic cod, are attempting to retreat further north. In the past half-decade, says Wassmann, “There has been (Atlantic) cod in fishable amounts north of Svalbard, which had not been observed before.”

One of the most striking trends is a rapid poleward spread of phytoplankton, the microalgae at the base of the marine food chain. A new study finds that Emiliania huxleyi, a phytoplankton native to more temperate, Atlantic seas, are blooming 5 degrees latitude, or roughly 350 miles, farther north in the European Arctic today than in 1989.

The northward spread of Atlantic phytoplankton could have a drastic effect on the Arctic marine ecosystem, says co-author Laurent Oziel, a polar oceanographer at Laval University in Quebec City. In the Arctic, the zooplankton that consume phytoplankton are specialized to store large reservoirs of fat to withstand harsh winter conditions. This makes them especially rich food sources for the fish that eat them, the seals that eat the fish, and on up to the top predators, such as polar bears. But the influx of southern phytoplankton is bringing in new types of zooplankton that are leaner and provide less nutrition for local species, Oziel says.

Southern zooplankton may not be able to survive the cold northern conditions. But Wassmann says that thinning and disappearing sea ice is allowing more light to penetrate the Arctic Ocean’s depths, stimulating algae growth that could allow fish and organisms to become established in places that previously lacked sufficient nutrients.

Atlantic influences are also being felt along the Canadian section of the Arctic Ocean. “In Hudson Bay we’ve seen a huge climatic shift in what we call subarctic species,” says Jennifer Provencher, a postdoctoral fellow in northern research at Acadia University in Nova Scotia. “We have documented that shifting occurring from cold-water species to the warmer water Atlantic species. In our case, it’s going from Arctic cod to much more capelin and sand lance.”

Advertisements

2 Responses to “The “Atlantification” of the Arctic”

  1. dumboldguy Says:

    “Reminder: Deep explainer interviews from Scientists like Dr. Barber happen because of your support for Dark Snow Project”.

    In case anyone missed it, Peter is saying that time is running out—-it will soon be time for him and the other Dark Snow folks to be making plane reservations—-if you haven’t yet anted up, please do so. IMO the Greenland ice sheet is key to the whole problem—-for those of us that fall asleep counting tipping points instead of sheep, it’s #1 on the list.

  2. Sir Charles Says:

    ” summer ice cover in the Arctic Ocean has declined by about 40 percent since satellite monitoring began “


Leave a Reply

Please log in using one of these methods to post your comment:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: