Monday, January 24

“Heat Dome” Likely Killed 1 Billion Marine Animals Off Canada’s Coast, Experts Say | Canada


More than 1 billion marine animals along Canada’s Pacific coast are likely to have died from last week’s record heat wave, experts warn, highlighting the vulnerability of ecosystems that are not used to extreme temperatures.

The “heat dome” that settled over western Canada and the northwestern United States for five days raised temperatures in communities along the coast to 40 ° C (104 ° F), breaking long-standing records. dating and offering little respite for days.

The intense and unrelenting heat is believed to have killed 500 people in the province of British Columbia and contributed to the hundreds of wildfires currently burning across the province.

But experts fear that it has also had a devastating impact on marine life.

Christopher Harley, a marine biologist at the University of British Columbia, has calculated that more than a billion marine animals may have died from the unusual heat.

A walk along a Vancouver-area beach highlighted the magnitude of the devastation caused by the heat wave, he said.

“The shore doesn’t usually creak when you walk on it. But there were so many empty mussel shells everywhere that you couldn’t help stepping on dead animals while walking, ”he said.

Harley was surprised by the smell of rotten mussels, many of which were cooked in abnormally hot water. Snails, starfish, and clams were rotting in the shallow waters. “It was a visceral and overwhelming experience,” he said.

As the air around Vancouver hovered around 30 degrees (around 100 ° F), Harley and a student used infrared cameras to record temperatures above 50 ° C (122 ° F) along the rocky shoreline.

“It was so hot when I was hanging out with a student that we collected data for a while and then we retired in the shade and ate frozen grapes,” Harley said. “But of course mussels, starfish, and clams don’t have that option.”

“One square meter of mussel bed could hold several dozen or even a hundred species,” said Christopher Harley. Photography: Christopher Harley

Mussels are hardy shellfish that tolerate temperatures up to 30 degrees. Barnacles are even hardier, surviving into the mid-40s (about 113 ° F) for at least a few hours.

“But when temperatures exceed that, those are insurmountable conditions,” he said.

The massive shellfish death would temporarily affect water quality because mussels and clams help filter the sea, Harley said, keeping it clear enough for sunlight to reach seagrass beds while creating habitats. for other species.

“One square meter of mussel bed could be home to several dozen or even a hundred species,” he said. The way mussels live, tightly packed, also informed Harley’s estimate of the extent of the loss.

“You can put thousands in an area the size of a stove. And there are hundreds of miles of rocky beach that are mussel-friendly. Every time the scale increases, the numbers get bigger and bigger. And that’s just mussels. A lot of marine life would have died. “

While mussels can regenerate over a two-year period, various starfish and clams live for decades and reproduce more slowly, so their recovery will likely take longer.

Harley has also received reports from colleagues about dead sea anemones, rockfish, and oysters.

Experts have warned that the province must adapt to the reality that sudden and sustained heat waves are likely to become more common as a result of climate change.

Another heat wave is expected to hit the western United States and southwestern Canada in the next week, highlighting the relentlessness of the dry summer heat.

“The nerdy green part of me is excited to see what will happen in the next few years,” said Harley. “But most of the rest of me is a bit depressed about it. Many species will not be able to keep up with the pace of change. Ecosystems are going to change in ways that are really difficult to predict. We don’t know where the tipping points are. “


www.theguardian.com

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