Map showing radiation measurements in the ocean

Twenty-five years ago today, the Chernobyl nuclear power plant in Ukraine exploded and burned, creating what was at the time the largest accidental release of radiation to the environment. Ken Buesseler was at the time a young MIT-WHOI Joint Program student in marine chemistry studying radiation in the North Atlantic from Cold War-era nuclear weapons testing. He and his colleagues immediately began tracking the fate of fallout from Chernobyl in the Black Sea. Although radiation levels there remain higher than most other ocean basins, the Black Sea is safe for swimming and fishing. Today, Buesseler finds himself monitoring releases from the Fukushima Daiichi power plant in northern Japan that was damaged following the March 11, 2011, earthquake and tsunami. (Illustration by Jack Cook, © Woods Hole Oceanographic Institution)