WASHINGTON, Aug. 30 (UPI) -- The remains of an ancient and extensive coral reef in the southern Pacific Ocean, the southernmost of any existing reef, have been discovered, researchers say.
A team of scientists from Australia and New Zealand used sonar and core samples to examine a relic reef found in water about 75 feet deep around Lord Howe Island 370 miles east of the Australian mainland, an article in the U.S. journal Geophysical Research Letters says.
The reef thrived from about 9,000 to 7,000 years ago, researchers say, and covered an area 20 times larger than the island's modern reef, the furthest south in the world.
About 7,000 years ago the reef was drowned, probably due to abrupt sea level rise, and then shrank to its current size.
Sensitive to climate change and variations in sea level, coral reefs exist mainly in shallow waters with surface temperatures higher than 64 degrees Fahrenheit at latitudes near the equator.
The relic reef shows corals previously existed at southern latitudes farther from the equator.
As ocean temperatures rise due to climate change, the ancient reef could become a substrate for new coral reef growth, the researchers say.
