Marine heatwaves need clear definitions so coastal communities can adapt
clearly communicating baselines for assessing ocean warming is essential for understanding extreme events and how they will affect marine ecosystems and livelihoods in the future.
Coral bleaching is developing in Japan’s largest coral reef, Sekiseishoko, which lies between Ishigaki and Iriomote islands. Credit: BJ Warnick/Kyodo/Newscom/Alamy
Marine heatwaves devastate ecosystems and the coastal communities that rely on them. Weeks, months or years of unusually warm waters can bleach corals, spur harmful algal blooms and wipe out seaweeds. They might kill or strand marine animals and disrupt food webs and fisheries1. Billions of US dollars are lost to such events around the world each year2.
For example, in 2013, an area of water in the northeast Pacific Ocean more than three times the size of Texas, known as The Blob, warmed by nearly 3°C. Over 18 months, these warm waters spread across the entire west coast of North America, from the Gulf of Alaska to the tip of the Baja Peninsula in Mexico. Seabirds starved and stocks of Pacific cod collapsed. Tuna moved north, as far as Alaska. Humpback whales drawn towards the coast became entangled in fishing nets. Mysterious creatures, such as glowing tropical sea pickles, or pyrosomes, arrived in northern waters.
Ocean scientists are striving to better understand such phenomena, and whether climate change is making marine heatwaves more frequent and more intense. But right now the field has a problem: the definitions and communications describing what a marine heatwave is are confusing. Read More..
