
On the coral reef, knowing who’s your friend and who’s your enemy can sometimes be a little complicated. Take seaweed, for instance. Normally it’s the enemy of coral, secreting toxic chemicals, blocking the sunlight, and damaging coral with its rough surfaces. But when hordes of hungry crown-of-thorns sea stars invade the reef, everything changes, reports a new study.
http://www.sciencedaily.com/releases/2015/08/150825205850.htm