When you think of a coral reef, it’s likely that images of colorful corals and equally vibrant tropical fish come to mind. The newest reef to be discovered though, is home to an intriguing array of corals that have developed the ability to thrive in cold water. Here, we’ll take a look at one of the most incredible discoveries in recent oceanographic history.
Tsushima Island
Japan’s Tsushima Island is located at 34 degrees north latitude, where the water is an average of 55 degrees Fahrenheit. The corals populating the reef are much different from other coral species; this is not surprising, since ninety percent of the planet’s coral reefs are located in tropical regions, where summer temperatures are warm, and where winter water temperatures stay at about 64 degrees Fahrenheit.
In 2001, a similar reef was found off the coast of Iki Island, which is also located in Japanese territory. At the time, the reef was believed to be the world’s northernmost; at 43 miles south of Tsushima Island though, it now takes second place. The next-closest coral reef is located 217 miles south of Tsushima, so it’s not surprising that researchers are amazed by the discovery they made recently.
Local folklorists and historians have been aware of the reef forever, as it poses a hazard to navigation. It is located in a murky inner bay, and is estimated to be about 4,300 years old. The water that would be uninhabitable to the corals most of us are used to though is ideal for sustaining the newly discovered species. A type of brown coral, and part of the Favia coral genus, the corals making up this reef are much hardier than Acropora corals, which we’re used to encountering in warm, tropical waters.
Scientists believe that the Tsushima Island Reef began building itself when the Tsushima Island Warm Current, which is a unique stream of warm water that washes along Japan’s northwestern coast, helped propel coral larvae into the bays around Iki Island and Tsushima Island. The team studying these reefs is currently on the lookout for additional reefs in similar areas throughout the region the current affects.
Reefs like the one at Tsushima Island may soon help scientists as they work to measure ecosystem changes throughout the planet’s ever-warming oceans. Researchers studying the two reefs have discovered that sometime during the last twenty years, Acropora corals have begun settling onto the reefs, which suggests that these corals are in search of new habitat where they will thrive. By comparing corals found along the oldest portions of the reef to those which are still developing, scientists will gain valuable information about the ways in which climate change and the warmer water temperatures that are accompanying it are affecting the reef ecosystems.
Tsushima Island is a beautiful island inhabited by deer, boars, and other wildlife. Cold water fish thrive in the Korea Strait, and scientists believe that as temperatures on the planet rise, warm-water species will move northward in a slow migration that Acropora coral are already beginning. Only time will tell, but this reef and others that may be discovered in the future might just become favorite tropical dive sites sometime in the future.