A marine heat wave hits the Pacific, raising fears

A marine heat wave hits the Pacific, raising fears

The phenomenon of this "marine heat wave" could be as damaging as the "drop" that caused algae blooms and killed sea lions several years ago.

The ocean off the western coast of North America is five degrees Fahrenheit warmer than normal after warming at an unusually fast rate, according to the U.S. National Oceanic and Atmospheric Administration (Noaa).

It has been dubbed the "2019 Northeast Pacific Marine Heat Wave."

Marine heat waves are defined as oceanic events in which the water surface temperature is warmer than 90% of past measurements for at least five days in a row. The current heat wave is the second largest since scientists began tracking the phenomenon in 1981, Noaa reported Friday.

If the abnormal patch does not dissipate soon, it could become as destructive as the so-called “drop” of warm water in the same area that, in 2014-2016, created toxic algal blooms, killed sea lions and endangered whales. force them to forage closer to shore.

Oceanographers began to notice something strange in June about a triangle-shaped ocean mass stretching from Alaska to Hawaii and Southern California. The direct cause of the heat is weak winds, though these conditions generally don't persist for months as they have this year. The warm water has also remained since the previous extreme heat event.

"It went from being a little warmer than average to almost as warm as we've seen in just three months," said Nate Mantua, a research scientist at the Noaa Southwest Fisheries Science Center in Santa Cruz, California.

"It is not clear to me that there is a simple link between the persistence of this climate pattern and longer-term climate change," Mantua added. “There could be. It is still an evolving field and there are many open questions. "

The oceans have absorbed about 90% of the excess heat related to the climate crisis. "That has been going on over many decades, and it is a slow process compared to this event, which happened in just three months," Mantua said.

It is also not known whether there have been large impacts on marine life, mainly because researchers have relatively little monitoring equipment in the 4 square miles of affected ocean. Oceanographers are beginning to see subtle effects on the distribution of some species, Matua said, such as tuna that are found closer to shore to avoid warmer waters.

The impact has been mainly limited to the upper 50 meters of the ocean. "If it persists for a year or two, the warming will penetrate deeper," Mantua said.

Video: Hawaii corals suffer amid Pacific heatwave (September 2021).