Tipped off by the smell on the Sunday morning of the heat wave, Harley and a team of student researchers began to canvas multiple coastlines, including those in West Vancouver and on the Sunshine Coast. And on Saturday, Sunday, Monday, during the heat wave, it just got so hot that the mussels, there was nothing they could do." Water quality will be impacted "They are stuck there until the parent comes back, or in this case, the tide comes back in, and there's very little they can do. "A mussel on the shore in some ways is like a toddler left in a car on a hot day," Harley said. Intertidal animals such as mussels, which live where land and sea meet, can endure temperatures in the high 30s for short periods of time, Harley said.īut the scorching heat, combined with low tides in the middle of the afternoon, created a dangerous combination for more than six hours at a time. (Chris Harley/University of British Columbia) The scale bar on the right shows the hottest and coolest temperatures recorded in the image. During the decaying process, oxygen is absorbed, causing the oxygen concentrations in the water to become so low that animals die.A thermal image of recently killed mussels in Lighthouse Park in West Vancouver, B.C., captured on June 28. Incidentally, heat can also be harmful for other reasons, says De Voogd: for example, it can stimulate the growth of algae. If temperatures remain high for too long, large areas of reef can die.
At too high temperatures, the corals repel these micro-organisms, causing them to bleach and threaten food shortage. ‘Certainly organisms that are stuck and that cannot ‘flee’, such as mussels.’ Many coral reefs also do not tolerate heat well: tropical corals live together with micro-organisms that convert sunlight into food, like plants do. Mussels and cockles have also died in the Dutch seas during heat waves in the past.Īnimals in shallow water are most sensitive to acute heat, because water warms more slowly at greater depths. It is a well-known phenomenon that it sometimes gets so hot that sea creatures die as a result, says Nicole de Voogd, professor by special appointment of marine ecosystems at Leiden University and affiliated with Naturalis.
“But the biggest concern is that these kinds of damaging heat waves will become so common that species never fully recover.” The question is what the mass mortality means for the rest of the ecosystem, such as the spectacled scoter, which overwinters in the area and will miss out on a lot of food. Many species will recover in a few years, he expects, although some slow-reproducing shells may take longer. “We’ve measured temperatures on the rocks that are higher than I’ve ever experienced in this part of the world.” It is striking that especially animals that sit in the shade are still alive. The cause of the coastal die-off is also undoubtedly the heat, according to marine biologist Harley. For example, there is a real risk that most of the Chinook salmon fry in the Sacramento River will not survive the summer because of the warm weather, writes the California Department of Fish and Wildlife.
It doesn’t stop with marine life: there are also major concerns about the fate of salmon in rivers on the west side of America. It is difficult to estimate exactly how many animals have died in this coastal area, but it will be billions, he says. ‘We are only now beginning to see how extensive the damage is among the barnacles, now that parts of their shells are washed away and they appear to be dead and empty.’ Tens of millions of dead barnacles lie on a one-kilometre stretch of coastline alone on a beach near the town of White Rock, near biologist Harley, he says. Animals that live in the tidal area, such as starfish, mussels and other shellfish, have died en masse. “It’s like a catastrophic building collapse, where the death toll continues to rise and you’re glad to find survivors,” said Christopher Harley, a marine biologist at the University of British Columbia. A harbinger of what global warming could bring about, biologists fear. The heat now also hits aquatic life hard. Researchers calculated the probability that the late June heat wave would occur, and concluded that it is virtually impossible that it could have happened without climate change. Heat record after heat record has been set on the west coast of the US and Canada in recent weeks. Not only marine animals suffer from the extreme heat on the west coast of North America, coral reefs can also bleach when temperatures are too high.