Acidic oceans could stunt the growth of the world’s coral reefs by 2100, researchers say

Researchers study a patch of Australia’s Great Barrier Reef. Scientists say unless the world starts controlling its carbon dioxide emissions, coral reefs will see severely stunted growth by the end of the century.
(California Academy of Science/Aaron Takeo Ninokawa)

Researchers fast-forwarded ocean acidification in the Great Barrier Reef to study its impact on corals.

They found that the growth of corals was slowed due to a lack of minerals.

Unless the world starts controlling its carbon dioxide emissions, coral reefs will see severely stunted growth by the end of the century, according to a recent study.

Researchers analyzed the Great Barrier Reef and determined that ocean acidification is depleting the calcium carbonate corals used to form and maintain their skeletons. Additionally, organisms such as crustaceans are affected, as they rely on the compound to form and strengthen their shells.

“Our findings provide strong evidence that ocean acidification will severely slow coral reef growth in the future unless we make steep and rapid reductions in greenhouse gas emissions,” study lead author and California Academy of Sciences researcher Rebecca Albright said in a release on the study.

The scientists came to their conclusions by testing a small patch of the Great Barrier Reef. They introduced carbon dioxide to the reef in order to increase the acidity, which resulted in a 34 percent drop in calcification across the entire study area, Earther reports.

For their study, the researchers raised the acidity of the water in the test area to the level some researchers say could be the norm by 2050, reports ABC. According to Albright, the impact was very large from a very small change: they only reduced the water’s pH levels by 0.1.

In 2016, the research team used the same patch of reef to test the opposite reaction, exposing the corals to lower acidification levels, according to the release.

“Last time, we made the seawater less acidic, like it was 100 years ago, and this time, we added carbon dioxide to the water to make it more acidic, like it could be 100 years from now,” Carnegie Institution for Science researcher Ken Caldeira explained in the release. In their previous study, found that the corals’ ability to form improved.

The ocean’s shift towards its more acidic side has largely been driven by global warming and fossil fuel emissions. Since the Industrial Revolution period, the air has become 30 percent more acidic, according to NOAA. Oceans soak up roughly 30 percent of the carbon dioxide in our atmosphere, which raises its levels and triggers an increase of hydrogen ions, making the water more acidic and depleting the carbon ions corals need to grow.

Albright says the ocean acidification would also prevent reefs from being able to recover from mass coral bleaching events, which have been taking a toll in recent years, ABC reports.

Coral bleaching occurs when ocean waters warmed by climate change causes corals to release the algae that provided their color and food, according to a previous report. The corals can’t cool down and find new algae fast enough, which causes them to die out and become a milky shade of white before they begin to decompose and attract turf algae.

“Temperature and ocean acidification are acting in tandem at different scales and on different processes, but they’re both eroding away the resilience of these systems,” Albright told ABC.

“For the denizens of the reef, there’s not a moment to lose in building an energy system that doesn’t dump its waste into the sky or sea,” said Caldeira

Ada Carr, The Weather Channel, 15 March 2018. Article.

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