Telegraph: But now tropical coral reefs are facing a renewed – and hidden – threat from environmental change which is stunting their growth, claim scientists. Researchers looking at the world’s biggest and best preserved reef – the Great Barrier Reef – found that it is growing at its slowest rate for at least 400 years. While the damage is not visible to the naked eye scientists believe it is a “very worrying” indicator which could spell disaster for the biodiversity of the …