Coral catastrophe: The fight to save our dying reefs

A team of scientists are using assisted evolution to grow “super coral” that can withstand climate change.

Pollution, global warming, and other man-made problems are pushing the world to the brink of an ecological disaster.

Climate change has a profound effect on our marine ecosystems and down in the oceans it’s taking its toll: corals around the world are dying.

According to a report from the World Wide Fund for Nature, coral reef cover has declined by 50 percent in the past 30 years, and coral reefs could disappear by as early as 2050.

“Today, we are facing the potential loss or massive degradation of all our reefs,” says Dr Ruth Gates from the Hawaii Institute of Marine Biology.


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“If we don’t have coral reefs, we will have people who don’t have food, who will have to move, whose lands at the entire islands will be eroded, and the tourist economy of many of these places will be completely obliterated,” she explains.

Corals are living, dynamic animals with an existence entirely unto themselves. Marine life exists within the reef, depending on it as a source of food or a place to hide from floating prey.

These animals are characterised by its diversity and thrive in full and vibrant colour but, lately, corals are changing.

Higher-than-normal water temperatures cause corals to expel the symbiotic plant cells which provide them with food, and without the algae the corals begin to starve – turning healthy brown coral ghostly white. This phenomenon is known as bleaching. 

“Corals aren’t doing very well … and they are not doing well for a variety of reasons. First of all, we have changes in our global ocean that relate to climate change, so the ocean is getting warmer and more acidic, and corals don’t like warm water, and they definitely don’t like water that is a little bit lower in PH,” Gates explains. 

Triggered by El Nino in 2015, a global weather phenomenon which causes already rising sea temperatures to spike even higher, corals faced a massive bleaching, and for the third time in history, scientists declared the bleaching a global event. 

Today approximately 38 percent of the world reefs are bleached – from Australia’s Great Barrier Reef to the Caribbean to the islands of the South Pacific.

“Bleached corals when they’re first white yet aren’t dead. They are at this moment in time when they can go in two directions … they can either re-brown [and recover or] if the conditions that are causing the coral to be so perpetuate … that coral will die. There’s no way back,” says Gates.

However, to stabilise and restore coral reefs, a team of scientists at the University of Hawaii’s Institute of Marine Biology are intervening by attempting to breed “super coral”. They are taking samples from the reef, bringing them back to the lab, and apply techniques in assisted evolution to create a hardier, more resilient tool that can withstand climate change.

This is the first step in a process called transgenerational acclimatisation, in this case pre-conditioning an adult to ocean acidification and then measuring whether the offsprings are then better equipped to handle that same stress event.

The key with assisted evolution is epigenetics, that is, taking the genes of resilient coral strains and passing them on to younger offspring.

“What we are doing is assisting the evolution of coral, we are trying to accelerate the rate in which they do things to keep pace with the rates of change that are in the environment today that associates with climate change,” says Gates.

Ocean acidification and baby oysters

Techknow also travels to Tomales Bay, California, where the oyster business is booming. But climate change is a reality there and oyster farmers are fighting a hidden enemy – ocean acidification.

“Right now it’s getting bad enough that the oysters are stressed by it, or it’s not easy [for them] to make a shell,” Tessa Hill, from UC Davis Bodega Marine Lab, explains. 

Ocean acidification is caused by the addition of carbon gases in the ocean that has caused an increase in the presence of carbonic acid. That acid can be lethal to baby oysters, preventing them from forming shells, but even the mature oysters are vulnerable.

On TechKnow we explore the possible solutions, and how seagrass is showing some progress mitigating the effects of Co2 on the water.