Scientist Till Wagner & team member measuring the thickness and density of a recently extracted ice core that holds frozen clues from an ice floe drifting down the Fram Strait.
PHOTO: arwa damon/cnn
Scientist Till Wagner & team member measuring the thickness and density of a recently extracted ice core that holds frozen clues from an ice floe drifting down the Fram Strait.
Now playing
04:56
Arctic ice faces trouble from above and below
This image was taken during the first drive of NASA's Perseverance rover on Mars on March 4, 2021. The team has spent the weeks since landing checking out the rover to prepare for surface operations.
PHOTO: JPL-Caltech/NASA
This image was taken during the first drive of NASA's Perseverance rover on Mars on March 4, 2021. The team has spent the weeks since landing checking out the rover to prepare for surface operations.
Now playing
02:17
NASA releases stunning new images from Mars
PHOTO: ABC's "Jimmy Kimmel Live!"
Now playing
02:09
Sacha Baron Cohen plays Covid vaccine dealer to the stars
PHOTO: CNN
Now playing
04:37
Keilar calls out Tucker Carlson's show: Partisan junk food
PHOTO: MyHeritage
Now playing
01:01
Watch old photos come to life using AI
PHOTO: CNN/Getty Images
Now playing
06:46
McEnany says she expected 'peaceful' rally on January 6. Keilar rolls the tape
Now playing
01:26
No, Tom Cruise isn't on TikTok. It's a deepfake
PHOTO: ABC's "Jimmy Kimmel Live
Now playing
02:02
Eddie Murphy, Arsenio Hall reunite in 'Coming 2 America'
PHOTO: Courtesy AirlingRatings.com
Now playing
03:06
Virgin Atlantic CEO: We support Covid vaccine passports
Now playing
01:19
Warren proposes wealth tax: 'It's time for them to pay a fair share'
Now playing
01:43
Marriott CEO: Vaccinations are 'the key' to travel recovery
(CNN) —  

Climate change means melting ice and habitat loss for animals in the Arctic. But there’s an invisible side effect of warming temperatures and rising tides, and it’s killing key marine species.

Melting Arctic sea ice has opened new pathways for Arctic and sub-Arctic species to interact, and that contact has introduced a potentially deadly virus to mammals in the Northern Pacific Ocean, according to a new study in Scientific Reports.

Over 15 years, researchers identified two new channels linking the Atlantic and Pacific oceans between Russia and Alaska. Animals who live there are interacting for the first time, creating a reservoir of the deadly pathogen Phocine distemper virus.

The virus, also called PDV, was first identified in European harbor seals, killing thousands in 1988 and again in 2002. It reemerged in 2004, but this time in northern sea otters in Alaska.

It was surprising that the disease jumped to a different species in a different ocean, said study author Tracey Goldstein, associate director of One Health Institute at UC Davis School of Veterinary Medicine. It’s what led scientists to believe that melting ice was to blame for the infection’s spread.

“Animal health and human health and environmental health are so linked, if one deteriorates then the rest do, too,” she told CNN.

Infection peaked when ice was at its lowest

To evaluate the extent of the infection, researchers took nasal swabs and blood samples from more than 2,500 ice-dwelling seals, Steller sea lions and northern sea otters from Alaska to Russia living in its marginal seas and oceans.

Widespread exposure to the infection peaked twice, in 2003 and 2009. Both outbreaks were preceded by record-low sea ice, Goldstein said.

Ice is essential for marine mammals, she said. It’s where they breed, rest and give birth. When water temperatures warm, their food likely travels deeper into the ocean, so animals are traveling further to catch them, spreading the pathogen across large swaths of northern seas.

Animals can’t keep up with the rate of their rapidly changing environments, Goldstein said, and that makes them more susceptible to disease.

PDV has already impacted people

Goldstein compared PDV to measles in humans – both are highly contagious respiratory diseases that spreads easily through contact (though PDV doesn’t infect humans).

But it’s already indirectly impacted humans who rely on the animals. It’s harder for Alaskans to hunt and maintain their livelihood as seals and fish move further off-shore, she said.

Because the Arctic is so remote, it’s difficult to discern how many species have died from the virus since the start of the study, she said. Some, particularly European harbor seals, are more vulnerable than others – up to 50% of the harbor seal population died in the first two outbreaks, she said.

Outbreaks occur every five to 10 years, typically when ice is at its lowest. Sea ice cover in the Arctic hit its second-lowest level in 2019, according to NASA – and that could mean new paths opened up, linking animals in both oceans and increasing the likelihood of the virus’s reintroduction.

Eliminating the virus may be impossible, but humans can at least stall its spread, Goldstein said. Reducing the global carbon footprint can slow the effects of climate change and give animals a chance to catch up and adapt.