Aerial view of the Great Barrier Reef

The Great Barrier Reef, which today covers an area roughly the size of Germany, has shifted over time to chase its preferred conditions. Credit: Marco Brivio/Getty


Drilling reveals the Great Barrier Reef’s restless past

The world’s largest coral reef is a resilient nomad.

Australia’s iconic Great Barrier Reef, now under threat from climate change, has survived five environmental upheavals during the past 30,000 years.

Jody Webster at the University of Sydney, Australia, and his colleagues drilled 34 cores deep into the sea bed near the reef, capturing information about coral and algal species going back 30 millennia. Data from a selection of those cores show the reef’s nimble response to sea-level change.

As the reef chased the ideal depth, it grew laterally towards or away from the shore at rates of up to 1.5 metres a year. And, when the sea level rose, the reef grew towards the surface at a rate of as much as 20 metres per 1,000 years.

Rising water levels and thick sediment have already caused portions of the reef to die and will continue to kill coral. But the new data suggest that, in the past, the Great Barrier Reef has reconstructed itself over timescales of tens of thousands of years.