With every day that passes, concern grows over the survival of Earth’s coral reefs. Facing one of the worst bleaching events in recorded history, it has slowly made its way around the world, hitting the Caribbean, Australia, the Maldives, and even the remote Chagos islands. While reefs have previously bounced back from bleaching events, the duration and intensity of the current situation has many worried. This has led some researchers to search for novel ways to help protect the reefs from dying.
But for some corals, the warming of the ocean is all in a day’s work. From the remote Kimberly region of northwest Australia, to those on the shores of Samoa, some species of corals are exposed to high temperatures on a daily basis. As the tides go out, the shallow pools in which they live heat up and reach extreme temperatures, topping out at 35°C (63°F) in some places. This sweltering heat would be enough to cause most species to bleach, but somehow these special heat tolerant varieties manage to survive. And it is these impressive talents that researchers want to harness.
One group working out of the University of Western Australia is currently trying to hunt down exactly which genes are responsible for this heat resistance, but they are also looking at whether or not they could simply transplant the corals that can survive high temperatures onto the Great Barrier Reef, in the hope that they will repopulate it.
Another team of scientists from America have been looking at breeding together warm water and cold water corals, and found that they too have an increased resistance. Not only that, but they then passed this on to their offspring, with the mothers passing on more resistance than the fathers. This, they suspect, means that some of the genes involved are probably located on the mitochondria.
In a third series of experiments, both groups have also looked at “priming” corals to heat stress. They have found that by artificially exposing corals to warmer temperatures, they are then better able to deal with bleaching, perhaps because the genes involved with heat tolerance become primed. Eventually, the researchers want to create a program of “human-assisted evolution”, where they breed heat resistant varieties in controlled nurseries before planting them out on the reef.
But others have their doubts. Some warn that no one knows how these genetically altered corals will function in the wild, or what consequences there might be. By rushing ahead without thinking the full implications through, we may be making things worse. Not only that, but it can also act as a distraction from doing what needs to be done: stopping our carbon emissions.