Above photo: A school of yellowmouth barracudas in Scandola Marine Reserve, Corsica, France on June 17, 2017. The Mediterranean is home to nearly 10% of the world’s marine species. Alexis Rosenfeld / Getty Images.
Oxygen Loss, Extreme Heat And Acidification.
A new study has found that the planet’s oceans are experiencing a “triple threat” of oxygen loss, extreme heat and acidification.
The researchers discovered that, as global heating has worsened, increasing stress has been placed on marine species, with as much as 20 percent of the world’s oceans affected by these threats.
“The global ocean is becoming warmer, more acidic, and losing oxygen due to climate change. On top of this trend, sudden increases in temperature, or drops in pH or oxygen adversely affect marine organisms when they cannot quickly adapt to these extreme conditions,” the study said.
The first-of-its-kind study found that many vertical water column-compound extreme events occur in high latitudes and the tropics, last 10 to 30 days and reduce habitable space by as much as 75 percent.
Global heating, caused primarily by humans burning fossil fuels for energy, has led to compound events in the top 984 feet of the ocean being six times more intense and lasting three times longer than they did in the early 1960s, according to the study, as The Guardian reported.
“The impacts of this have already been seen and felt,” said lead author of the study Joel Wong, a researcher with ETH Zürich, as reported by The Guardian. “Intense extreme events like these are likely to happen again in the future and will disrupt marine ecosystems and fisheries around the world.”
The study, “Column-Compound Extremes in the Global Ocean,” was published in the journal AGU Advances.
As ocean temperatures rise, it not only affects marine life, but the intensity of tropical storms.
“The heat has been literally off the charts, it’s been astonishing to see. We can’t fully explain the temperatures we are seeing in the Atlantic, for example, which is part of the reason why hurricane season is such a concern this year,” said Andrea Dutton, a University of Wisconsin–Madison climate scientist and geologist who was not part of the study, as The Guardian reported. “It’s quite frightening.”
As the world’s oceans soak up excess carbon dioxide and heat from the burning of fossil fuels, the carbon leads to increased ocean acidity while depleting oxygen levels. This pushes fish and other species out of their normal habitats and dissolves the shells of marine organisms.
“This means that marine life is being squeezed out of places it is able to survive,” Dutton said, as reported by The Guardian. “People have to recognize that oceans have been buffering us from the amount of heat we have been feeling on land as humans, but that this hasn’t been without consequence.”