Quantcast
Environmental News for a Healthier Planet and Life

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

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

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.

 

Air France airplanes parked at the Charles de Gaulle/Roissy airport on March 24, 2020. SAMSON / AFP via Getty Images

France moved one step closer this weekend to banning short-haul flights in an attempt to fight the climate crisis.

Read More Show Less
EcoWatch Daily Newsletter
A woman looks at a dead gray whale on the beach in the SF Bay area on May 23, 2019; a new spate of gray whales have been turning up dead near San Francisco. Justin Sullivan / Getty Images

Four gray whales have washed up dead near San Francisco within nine days, and at least one cause of death has been attributed to a ship strike.

Read More Show Less
Trending
A small tourist town has borne the brunt of a cyclone which swept across the West Australian coast. ABC News (Australia) / YouTube

Tropical Cyclone Seroja slammed into the Western Australian town of Kalbarri Sunday as a Category 3 storm before grinding a more-than 600-mile path across the country's Southwest.

Read More Show Less
A general view shows the remains of a dam along a river in Tapovan, India, on February 10, 2021, following a flash flood caused by a glacier break on February 7. Sajjad Hussain / AFP / Getty Images

By Rishika Pardikar

Search operations are still underway to find those declared missing following the Uttarakhand disaster on 7 February 2021.

Read More Show Less
Indigenous youth, organizers with the Dakota Access and Line 3 pipeline fights and climate activists march to the White House to protest against pipeline projects on April 1, 2021. Bill Clark / CQ-Roll Call, Inc via Getty Images

By Jessica Corbett

Indigenous leaders and climate campaigners on Friday blasted President Joe Biden's refusal to shut down the Dakota Access Pipeline during a court-ordered environmental review, which critics framed as a betrayal of his campaign promises to improve tribal relations and transition the country to clean energy.

Read More Show Less