A new paper published in the Science Advances journal suggests that mild increases in ocean temperature are actually beneficial for coral growth.
Scientists studying coral reefs in Bermuda have concluded that rising seawater temperatures are beneficial to coral reefs—but only if the rate of increase is not too rapid or too excessive.
Over two years, scientists from the Scripps Institution of Oceanography at the University of California San Diego recorded environmental data like temperature, light, seawater chemistry and pH levels from two coral reefs in Bermuda. They also measured the calcification and growth rates of coral samples planted in the two reefs.
After studying their data, they concluded that changes in the seawater pH level had little effect on coral calcification. Rather, it was the seawater temperature that had more impact. Simply put, as the ocean temperature rose, so did coral growth.
However, this positive effect was possible only if the temperature increase was kept within a specific limit. It becomes detrimental if the temperature increase is too rapid or too much.
“At the present time, Bermuda's coral reefs appear to be faring reasonably well with high rates of coral production and calcification that appears to be temporarily offsetting the impact of ocean acidification,” said co-author Nicholas Bates, director of the Bermuda Institute for Ocean Sciences.
Chemical oceanographer Andreas Anderson cautioned that the results did not mean that corals were not negatively affected by rising acidity. “It just means that the positive effect of the warming may mask any negative effects from pH when you're within the natural variability of temperature,” he clarified.
However, the researchers pointed out that this could change in the future if carbon dioxide emissions continue at the present rates. If the oceans heat up too fast, it would prove to be harmful for the Bermuda corals.