Evolution of coral could help keep warming threat away

By Robert Gebelhoff  Washington Post

Warming ocean waters due to climate change have been ravaging coral reefs over the past few decades, but researchers have discovered that, with the help of some breeding, the threat may be kept at bay.

Some corals already have the genes needed to adapt to higher ocean temperatures, and researchers expect those genes will naturally migrate and mix with corals under stress over time, according to a study published in Science. And that process could potentially be sped up artificially.

"These mutations are already there, they just need to be spread out," said Mikhail Matz, an author of the study and a professor of biology at the University of Texas.

Giving coral evolution a boost isn't an entirely new concept. Some scientists have already suggested genetically modifying corals through artificial breeding, or doing the same for the tiny microbes that live inside corals and are essential to reef growth. This study shows that human interventions may indeed be possible soon.

The team discovered the heat tolerance genes while crossbreeding individuals of a branching coral (Acropora millepora) located on the far northern Great Barrier Reef with members of the same species about 335 miles further south. Those from the northern part of the reef passed on the genes to their offspring, which had 10 times the normal survival rate when exposed to higher temperatures.

The researchers believe the coral larvae had altered genes working in the mitochondria — which power the cells and are inherited solely from mother corals. This discovery may lead to greater understanding of how cells in corals react to heat — and how best to protect them from it. "The take-home message is that the genetic capacity is already there," Matz said.

Matz also believes this sort of polite evolution nudging may be applied to other marine animals — such as other species of coral, sea urchins, sea cucumbers and maybe even fish.

But that won't be enough to secure the safety of the world's reefs. They're also putting up with an increase in ocean acidification and greater threats of disease.