In The News

Bluefin Tuna Found Off Greenland Coast The Voice of Russia reports that scientists in Denmark discovered three Bluefin tuna in the chilly waters off the east coast of Greenland in 2012, an unusual find given that Bluefin tuna typically hail from the Mediterranean and the Gulf Coast of Mexico and are found in warmer climes. The tuna were found in waters with temperatures of about 13 degrees Celsius, several degrees warmer than is normally found off the coasts of Greenland and Iceland. Their presence this far north suggests the influence of climate change, according to the scientists quoted in the study.

The discovery of blue fin tuna off the coast of Greenland suggests the fish's adaptation to warming ocean temperatures. Photo: Rex Features, Voice of Russia

Arctic Mammals Metabolize Pesticides and May Limit Human Exposure

A study published recently in Environmental Toxicology and Chemistry shows that arctic caribou metabolize some current-use pesticides ingested in vegetation, and limit the exposure of humans, including those who eat caribou. Pesticides or heavy metals enter rivers or lakes and vegetation, where they are ingested by fish and mammals and, in turn, are consumed by other animals and humans. The substances can become biomagnified, or concentrated in tissues and internal organs, as they move up the food chain. Biomagnification has been implicated as the cause of higher concentrations of many long-used pesticides and other toxic chemicals such as PCBs found in wildlife and in Inuit and other aboriginal and non-aboriginal Northerners dependent on hunting.

Such "legacy contaminants" are now widely banned under the Stockholm Convention, and some have been replaced by current-use pesticides (CUPs). "This is good news for the wildlife and people of the Arctic who survive by hunting caribou and other animals," said Adam Morris, lead author of the study. "The lack of any significant biomagnification through the food chain indicates that there is very little risk of harm from exposure to these CUPs in this region."

A recent study shows that caribou have the ability to metabolize pesticides, thereby preventing them from accumulating in the food chain. Photo: Government of NW Territories, Division of Natural Resources

Waves Found on Ice-Free Ocean

National Geographic reports that scientists have recently measured waves in the Beaufort Sea, an area north of Alaska. Waves there are a new phenomenon made possible by melting sea ice. Because wave action breaks up sea ice, allowing more sunlight to warm the ocean, it can trigger a cycle that leads to even less ice, more wind, and higher waves, according to the report. Much of the region is now ice-free by September, and researchers were able to anchor a sensor to measure wave heights in the central Beaufort Sea in 2012.

"It is possible that the increased wave activity will be the feedback mechanism which drives the Arctic system toward an ice-free summer," write Jim Thomson of the University of Washington in Seattle and Erick Rogers with the Naval Research Laboratory (NRL) in Mississippi in the journal Geophysical Research Letters.

If winds can blow for a longer distance over the open ocean, they can produce higher and higher waves. Sea ice limits how far winds can blow, thus limiting the formation of waves.

"Future scenarios for reduced seasonal sea ice cover in the Arctic suggest that larger waves are to be expected," the study authors write. Big waves could be the new normal in the Arctic, says Darek Bogucki, a physical oceanographer who works in the Arctic but wasn't involved in the study.

That means changes for shorelines, which could start getting hit with larger and larger waves that speed erosion, he says. It could also change the amount of carbon dioxide being exchanged between the atmosphere and the ocean, potentially triggering the Arctic to release more greenhouse gas into the atmosphere. 

Researcher: Polar Bear Diets Will Diversify With Climate Change

Shrinking sea ice will likely result in more polar bears subsisting on land. Scientists studying polar bear diets have found the bears ingest a more diverse land-based repertoire than previously thought. Photo: Paul Souders, Corbis

Linda J. Gormezano, an ecologist at the American Museum of Natural History in New York City, has calculated what polar bears might have to eat to survive increasingly long ice-free seasons in the western part of Canada's Hudson Bay area (map). Gormezano, who presented her findings last month at the North America Congress for Conservation Biology in Missoula, Montana, suggested that the predators may be able to survive for six months on land-based foods, and, because of climate change, they may have to. Her analysis of polar bear poop and observations of behavior suggest that the bears eat lots of land food, including lesser snow geese and their eggs, as well as caribou. Other scientists have warned that a lack of sea ice due to warming temperatures in the Arctic—and declining seal prey populations—could drive this population extinct by 2020.