Quantcast

Loss of Arctic Sea Ice Eliminates Major Barrier for Parasites in Marine Mammals

Climate

By Tim Radford

The great Arctic thaw—up to 50 percent of sea ice by area and 75 percent by volume in the summer season—could be offering new opportunities for one of the planet’s most successful parasites. Toxoplasma gondii, an infection spread by almost all cat species, has been identified for the first time in the western Arctic Beluga whale.

Uw

The parasite—Toxoplasma gondii—commonly spread through most species of cats has recently been identified in the Arctic Beluga whale. Photo credit: Wikimedia commons

Toxoplasma is found almost everywhere that cats settle: domestic pets, ocelots, cougar, wild cats all carry and spread oocysts of the parasite (structures it uses to transfer to new hosts) in their feces, to be spread further with discarded cat litter.

The parasite is notoriously hard to kill. Scientists store their samples in sulphuric acid, and the creature can survive unharmed in bleach. It is, however, routinely killed by freezing conditions, or boiling water.

The suspicion is that with the steady, sustained warming of the Arctic over the past 30 years, chiefly because of a buildup of carbon dioxide in the atmosphere, the retreat of the ice has begun to allow new traffic in parasite infections.

Another parasitic killer, a new strain called Sarcocystis pinnipedi, normally found only in the highest, iciest latitudes, has been linked with mass deaths too—406 grey seals died in 2012 in the north Atlantic. It has also been observed to kill Steller’s sea lions, Hawaiian monk seals, walruses, grizzly bears and polar bears as far south as British Columbia.

In the case of Toxoplasma, warming polar summers could have created conditions in which the parasite could find new warm-blooded hosts further north. In the case of the second parasite, the loss of ice has meant a greater mixing of species, and allowed Sarcocystis to find new hosts in warmer waters.

“Ice is a major barrier for pathogens,” Michael Grigg, of the U.S. National Institutes of Health told the American Association for the Advancement of Science annual meeting here. “What we are seeing with the big thaw is the liberation of pathogens gaining access to vulnerable new hosts and wreaking havoc.”

Toxoplasma can also infect people: it is the leading cause of infectious blindness in humans, and can be dangerous to unborn children and to people with compromised immunity.

It has been found in human communities in northern Quebec, perhaps spread by the consumption of dried seal meat. The discovery of Toxoplasma in Beluga whales has begun to worry health officials. Belugas are part of the traditional diet of the Inuit hunters of the far North.

Seals, walruses and polar bears are all what scientists like to call “ice obligate animals”: the ice sheet provides them with their preferred habitat. With the loss of the ice, new species are colonizing the Arctic, and those creatures that cannot now use the ice sheet have been forced to invade new habitats.

“Marine mammals can act as ecosystem sentinels because they respond to climate change through shifts in distribution, timing of their movements and feeding locations,” said Sue Moore of the U.S. National Oceanic and Atmospheric Administration. “These long-lived mammals also reflect changes to the ecosystem in their shifts in diet, body condition and physical health.”

Visit EcoWatch’s BIODIVERSITY and CLIMATE CHANGE pages for more related news on this topic.

 

EcoWatch Daily Newsletter

Yulia Lisitsa / iStock / Getty Images Plus

By Brianna Elliott, RD

Collagen is the most abundant protein in your body.

It is the major component of connective tissues that make up several body parts, including tendons, ligaments, skin, and muscles.

Read More
Greenpeace activists unfurl banners after building a wood and card 'oil pipeline' outside the Canadian High Commission, Canada House, to protest against the Trudeau government's plans to build an oil pipeline in British Colombia on April 18, 2018 in London. Chris J Ratcliffe / Getty Images

By Jessica Corbett

In an open letter to Canadian Prime Minister Justin Trudeau and Deputy Prime Minister Chrystia Freeland, 42 Nobel laureates implored the federal government to "act with the moral clarity required" to tackle the global climate crisis and stop Teck Resources' proposed Frontier tar sands mine.

Read More
Sponsored
Mapping Urban Heat through Portland State University / video

Concrete and asphalt absorb the sun's energy. So when a heat wave strikes, city neighborhoods with few trees and lots of black pavement can get hotter than other areas — a lot hotter.

Read More
Pexels

By Ryan Raman, MS, RD

Vitamin C is an essential vitamin, meaning your body can't produce it. Yet, it has many roles and has been linked to impressive health benefits.

Read More
The Rio San Antonio, in the headwaters basin of the Rio Grande in New Mexico, will lose federal protections under a new rule. Bob Wick / BLM California

By Tara Lohan

The Santa Fe River starts high in the forests of New Mexico's Sangre de Cristo mountains and flows 46 miles to the Rio Grande. Along the way it plays important roles for wildlife, irrigation, recreation and other cultural uses, and provides 40 percent of the water supply for the city of Santa Fe's 85,000 residents.

Read More