As Ocean Temperatures Rise, Corals Are Steadily Moving Poleward

A reef study site on the Palmyra Atoll, which lies between Hawaii and American Samoa.

A reef study site on the Palmyra Atoll, which lies between Hawaii and American Samoa. NICHOLE PRICE/BIGELOW LABORATORY FOR OCEAN SCIENCES

Rising ocean temperatures are increasingly causing coral reefs to shift away from the equator into more temperate waters. Over the past 40 years, the number of young corals has declined by 85 percent on tropical reefs, while at the same time doubling in cooler regions, according to a recent study published in the journal Marine Ecology Progress Series.

The findings are the latest evidence of how climate change is causing marine species to abandon their historic ranges and shift to cooler waters.

“The clarity in this trend is stunning,” Nichole Price, a senior research scientist at the Bigelow Laboratory for Ocean Sciences in Maine and lead author of the paper, said in a statement. “We don’t yet know whether the new reefs can support the incredible diversity of tropical systems.”

Price and his colleagues, an international team of collaborators from 17 institutions and 6 countries, examined coral settlement trends up to 35 degrees north and south of the equator. They found that reefs were shifting poleward equally on either side of the equator, and said the new reef locations could help provide refuge to other marine species moving in response to climate change. But the scientists also said that because of the cost to collect and analyze species data on reefs, they are not sure which coral species are migrating poleward and which ones aren’t. They also are unsure how well these new reefs will fare in their new locations over the long-term.

“The changes we are seeing in coral reef ecosystems are mind-boggling,” Price said. “We need to work hard to document how these systems work and learn what we can do to save them before it’s too late.”

For more on how marine species are shifting in response to climate change, click here.