Global Warming’s Toll on Coral Reefs: As if They’re ‘Ravaged by War’

  • 6 years ago
Global Warming’s Toll on Coral Reefs: As if They’re ‘Ravaged by War’
Before we call rockfish, shrimp and crab “dinner,” some of these species call coral reefs “home.”
But those reefs, home to a quarter of all marine fish species, are now increasingly threatened as rising ocean temperatures accelerate a phenomenon known as coral bleaching.
If corals can’t adapt quickly enough, “we could be looking at the effective loss of most of the world’s coral reefs,” said Mark Eakin, an oceanographer
who is coordinator of the Coral Reef Watch project at the United States National Oceanographic and Atmospheric Administration.
“La Niña periods today are actually warmer than El Niño periods were 40 years ago,” said Terry Hughes, a senior researcher
who specializes in coral reefs at James Cook University in Australia and the lead author of the Science study.
While many mass bleachings were prompted by El Niño events, which tends to warm Pacific Ocean temperatures, the bleaching event
that hit the Great Barrier Reef in 2017 — the reef’s first back-to-back bleaching — occurred at the beginning of a La Niña event, when ocean waters should have been cooler.
“The ecological effect of more and more bleachings is
that it’s changing the mix of species in favor of the tougher corals that can survive bleaching events and in terms of the corals that bounce back the quickest,” said Dr. Hughes.
But in the years since, according to a study published Thursday in the journal Science, the frequency of coral bleaching has increased to the point
that reefs no longer have sufficient recovery time between severe episodes.
In addition to giving coral reefs their bright colors, zooxanthella also provide
corals with oxygen, waste filtration, and up to 90 percent of their energy.

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