Heat waves marine devastate already the fauna and flora of the oceans

Les canicules marines dévastent déjà la faune et la flore des océans

Photo: Rod Salm / The Nature Conservancy
Corals face a grim future: even if humankind manages to limit global warming, between 70 % and 90 % of them are doomed to disappear.

Imperceptible to humans, but deadly to the life in the ocean, the heat waves and marines have already damaged the ecosystems of the world and should in the future prove to be even more destructive, according to a study published Monday.

Since the mid-Twentieth century, the number of days of marine heatwave has increased by over 50 %, ” note the authors of the study published in the journal Nature Climate Change. A marine heatwave is defined by temperatures that remain close for 5 days of records stored in a given area.

“On a global scale, the heat waves navy became more frequent, and longer and longer. Over the last decade, the events records have been observed in most ocean basins, ” says Dan Smale, of the Marine Biological Association of the United Kingdom.

“Just as the waves of heat air can be fatal to crops, forests and animals, excessive heat, marines can be devastating to the ocean ecosystems “, explains to the AFP Dan Smale.

But compared to the hot weather (that have tens of thousands of victims since the beginning of the century), these events sailors have been the subject of quite a few scientific studies.

The corals are the victims par excellence of these heat waves in shallow water and face a grim future : even if humankind manages to limit global warming to 1.5 degrees Celsius — an impossible task, according to some scientists — between 70 % and 90 % of the corals are doomed to disappearance, according to a report by the IPCC released in October.

But they are not the only ones : the heat wave of 2011 has killed extensive areas of seagrasses and kelp forests, as well as fish and abalone, which depend on it.

In 2014, the “Blob ” has warmed the waters off the coast of California at 6 °C for more than a year, causing the proliferation of toxic algae to the crabs, sea lions, whales, and seabirds…

The intensification of heat waves of the sea (in number and in power) also has a direct impact on the man.

“The species of fish and shellfish intended for consumption may be lost locally “, alarm Dan Smale. In addition, “if the sea grasses and mangroves are affected by extreme temperatures, they can release the carbon they store” and increase the global warming, adds the researcher.