New study provides first comprehensive look at oxygen loss on coral reefs


A NEW study is providing an unprecedented examination of oxygen loss on coral reefs around the globe under ocean warming. Led by researchers at UC San Diego’s Scripps Institution of Oceanography and a large team of national and international colleagues, the study captures the current state of hypoxia—or low oxygen levels—at 32 different sites, and reveals that hypoxia is already pervasive on many reefs.

The overall decline of oxygen content across the world’s oceans and coastal waters—a process known as ocean deoxygenation—has been well documented, but hypoxia on coral reefs has been relatively underexplored. Oxygen loss in the ocean is predicted to threaten marine ecosystems globally, though more research is needed to better understand the biological impacts on tropical corals and coral reefs.

The study, published on

March 16 in the journal Nature Climate Change, is the first to document oxygen conditions on coral reef ecosystems at this scale.

“This study is unique because our lab worked with a number of collaborators to compile this global oxygen dataset especially focused on coral reefs—no one has really done that on a global scale before with this number of datasets,” said marine scientist Ariel Pezner, now a postdoctoral fellow at the Smithsonian Marine Station in Florida. “We were surprised to find that a lot of coral reefs are already experiencing what we would define as hypoxia today under current conditions.”

The authors found that low oxygen levels are already happening in some reef habitats now, and are expected to get worse if ocean temperatures continue to warm due to climate change. They also used models of four different climate change scenarios to show that projected ocean warming and deoxygenation will substantially increase the duration, intensity, and severity of hypoxia on coral reefs by the year 2100. – Eureka Alert

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