News that half the corals in the Great Barrier Reef have been lost in the past two decades is alarming enough, but experts say alarm at findings of dramatic coral losses is drowning out even greater concerns for survival of the entire marine ecosystem.

The Centre of Excellence for Coral Studies published findings this week that the number of corals have halved in the past twenty years, on average across the 340,000 square kilometre reef.

But the report also warned that, like old growth trees in a forest, corals are a keystone species for the reef’s vibrant marine life and the vast scale of destruction risked “cascading effects on community composition and ecosystem functioning”.

Centre of Excellence for Coral Studies professorial fellow Andrew Baird said "there is so much life visible underwater in the marine environment".

Read the full article on The Sydney Morning Herald website, featuring commentary by Prof David Lindenmayer