Warming water can create a tropical ecosystem, but a fragile one
A decade ago, the waters off the Otomi Peninsula in the Sea of Japan, were a tepid haven. Schools of sapphire damselfish flitted above herds of long-spined urchins. The site was a hot spot of tropical biodiversity far from the equator, thanks to warm water exhaust from a nearby nuclear power plant. But when the plant ceased operations in 2012, those tropical species vanished. After the plant shut down, Otomi’s average bottom temperature fell by 3 degrees Celsius, and the site lost most of its tropical fishes, fisheries scientist Reiji Masuda of Kyoto University reports May 6 in PLOS ONE. The die-off of tropical fishes and invertebrates was “striking,” he says. Otomi quickly reverted to a cool-water ecosystem. The life and death of the reef is providing a sneak peek into the future of temperate habitats under climate change. This research suggests that even modest warming can result in dramatic changes to cool-water reefs, with some temperate habitats converting to more...