Here’s some cheery news to lighten all the grim findings about the bleaching of much of the Great Barrier Reef: Australian scientists have stumbled onto a new reef off the coast of Queensland. At 46 square miles, the reef can’t hold a candle to its 133,200 square-mile big brother, but it’s still bigger than, for example, all the reefs in Barbados combined. In addition to remaining hidden from generations of explorers — probably because of its remote location and its average depth of more than 65 feet below the surface — the reef has turned conventional scientific wisdom on its head by showing that hard coral can grow in Australia’s warm, muddy coastal waters. That finding suggests that other new reefs could also be found in the region: “I’m very curious to see if this sort of thing is not more widespread,” said Peter Harris, who led the expedition that encountered the new reef. He said he was “absolutely stunned” by the discovery.