Scientists are pretty good at recognizing marine heat waves: A global network of thousands of oceanic buoys and orbiting satellites allow them to see, in real time, ocean surface temperatures, changing currents and storm systems as they develop, move or stall from the Antarctic to the North Pole. What’s harder to see is what’s happening to the marine ecosystems below — to the fish, invertebrates, plants and mammals. Some animals may move down the water column to darker, colder waters. Others may move north — or south — depending upon where the cooler waters are. Many may flourish; others will perish. And some may not be affected at all, new research shows.