Reuters: Coral growth since 1990 in Australia’s Great Barrier Reef has fallen to its lowest rate for 400 years, in a troubling sign for the world’s oceans, researchers said on Thursday. This could threaten a variety of marine ecosystems that rely on the reef and signal similar problems for other similar organisms worldwide, Glen De’ath and colleagues at the Australian Institute of Marine Science said. The Great Barrier Reef is the world’s largest coral expanse, and like similar reefs …