The Great Barrier Reef Lost Half Its Corals In The Last Two Years

Rising temperatures have a devastating impact on the planet's marine ecosystems, and the world's coral reefs are paying a heavy toll. Half of all the corals in the Great Barrier Reef have died since 2016, NPR reports.

The data comes from marine biologists at James Cook University in Queensland, Australia, who published a study investigating the dramatic consequences of the unprecedented heatwave that led to the coral bleaching event of 2016.

The paper, featured yesterday (April 18) in the journal Nature, documents the "catastrophic" repercussions of the "record-breaking" undersea heatwave and how it irreversibly changed the 3,863 reefs that make up the world's largest coral reef system.

A staggering 29 percent of the corals in the Great Barrier Reef perished in 2016 as a direct consequence of global warming reveals the research conducted by scientists from the Australian Research Council (ARC) Center of Excellence for Coral Reef Studies at the university, in collaboration with the U.S. National Oceanic and Atmospheric Administration (NOAA) in Maryland.

The long-lasting heatwave initially struck staghorn and tabular corals, the authors note in their paper. These two types of fast-growing corals were the most affected, experiencing a massive die-off.

Since even the fastest-growing corals need about a decade to regenerate, these corals were not able to recover. Their destruction led, in turn, to the destabilization of the entire coral reef system, which ultimately wiped out a third of the Great Barrier Reef, the study shows.

The video below, taken in November 2016 by the ARC team, illustrates the aftermath of the extensive bleaching event that took place two years ago. The footage shows the devastation of Australia's Zenith Reef located in the northern section of the Great Barrier Reef.

As if the situation was not dire enough, last year the world's largest reef system was pummeled by yet another ocean heatwave. This event, which was not included in the study, resulted in disaster, completely changing the face of the Great Barrier Reef.

According to study leader Terry Hughes, who also runs the ARC research center, the 2017 undersea heatwave killed 20 percent of corals in the entire reef, reports the Washington Post.

This brings us to a grim reality: half the corals in the Great Barrier Reef have died in the last two years.

"What we just experienced is one hell of a natural selection event," Hughes said in a statement.

The researchers warn that the damage is irreversible and that it may forever change the global marine ecosystem.

"Now that these marine heat waves are coming more frequently and more severely, we expect this sort of damage to keep occurring on coral reefs around the world," said study author Mark Eakin, who coordinates NOAA's Coral Reef Watch.

The study's bleak conclusion is that the ocean is changing dramatically under the effects of global warming.

The bleaching phenomenon that struck Great Barrier Reef two years in a row "has changed the whole community of coral living on many of these reefs, killing many of the more temperature-sensitive corals and just leaving a community that's been sort of flattened or homogenized," Eakin explained.