Coral reefs are typically found in the warm, clear waters of the tropics and subtropics. Researchers in Japan have recently discovered a coral reef far north of any previously discovered on the planet, off the coast of Japan’s Tsushima Island at 34 degrees north latitude. As a reference, this would put the reef north of the city of Atlanta, Georgia. While cold water and deep water corals are found in polar regions, the types of reef-building corals discovered in Japan are generally much more sensitive to cold water and to cloudy or turbid waters, making this discovery all the more remarkable, especially in light of winter water temperatures of 13 degrees Celsius (55 degrees Fahrenheit), considered extremely low and most often fatal to most coral reefs.
From Discovery News:
So why did this reef start building itself in such an unfriendly environment? The team isn’t sure, but Yamano thinks the Tsushima Warm Current, a stream of warm water flowing along the northwestern coast of Japan, probably helped transport coral larvae northward into the turbid inner bays of Iki and Tsushima islands. Yamano thinks there may be many more undiscovered reefs in similar settings throughout the region.Reefs like this one might help researchers measure ecosystem changes in warming oceans.? Although the Tsushima and Iki reefs both formed in very cold waters and predominantly house Favia coral species, Acropora corals have begun settling near the reefs over the last 20 years. Comparing coral species in older parts of the reef to newly arrived corals might help scientists determine how climate change and warming waters are affecting these reef ecosystems, Yamano said.