Australia's Great Barrier Reef is in trouble. According to a new study, the amount of coral cover in the reef has dropped by 50.7% in the past 27 years. And nearly half of the damage is attributed to predatory crown-of-thorns starfish, which are eating through coral polyps at an alarming rate. Read more about these ravenous starfish and other threats to the world's largest coral reef in my blog post here.