The ocean is heating up. That's the conclusion of a new study that finds that Earth's oceans now 26_______ heat at twice the rate they did 18 years ago. Around half of ocean heat intake since 1865 has taken place since 1997, researchers report online in Nature Climate Change. Warming waters are known to 27______ to coral bleaching(珊瑚白化)and they take up more space than cooler waters, raising sea 28_______ . While the top of the ocean is studied, its depths are more difficult to 29______ . The researchers gathered 150 years of ocean temperature data in order to get better 30_______ of heat absorption from suce to seabed. They gathered together temperature readings collected by everything from a 19th century 31______ of British naval ships to modern automated ocean probes. The extensive data sources, 32________ with computer simulations(计算机模拟), created a timeline of ocean temperature changes, including cooling from volcanic outbreaks and warming from fossil fuel 33_______ . About 35 percent of the heat taken in by the oceans during the industrial era now residents at a 34________ of more than 700 meters, the researchers found. They say they're 35 ______ whether the deep-sea warming canceled out warming at the sea's suce.