For decades, the Great Barrier Reef has captivated the imagination of people from around the world for its pristine waters and diverse and colorful aquatic life. Its breathtaking beauty has even earned it a spot as one of the new seven natural wonders of the world.
However, this great coral reef system has had its fair share of degradation in recent years as a consequence of drastic changes in the environment including global warming.
The continued heating of the Earth and its waters has increased pressure on the corals, resulting in mass bleaching. While this may not outright kill the corals in the Great Barrier Reef, it leaves them more vulnerable to mortality.
This is what inspired researchers from the University of Texas at Austin and the Oregon State University in the United States and the Australian Institute of Marine Science (AIMS) in developing a new way to preserve the corals of the Great Reef.
Texas biologist Mikhail Matz and his colleagues studied the effects of crossing corals collected from warmer areas in the Great Barrier Reef with those taken from naturally cooler latitudes around 300 miles south of the reef system.
They discovered that coral larvae taken from northern areas, where the average water temperature is about two degrees Celsius warmer, 10 times more likely to survive stress from heat compared to those taken from the southern areas.
Through the use of genomic tools, the researchers were able to identify the biological process in the corals that allows them to become more tolerant to the heat. They used an existing genetic variation to demonstrate how the heat tolerance of the corals could evolve rapidly.
"Our research found that corals do not have to wait for new mutations to appear. Averting coral extinction may start with something as simple as an exchange of coral immigrants to spread already existing genetic variants," Matz explained.
"Coral larvae can move across oceans naturally, but humans could also contribute, relocating adult corals to jump-start the process."
These results are supported by an earlier study featured in the Global Change Biology journal. The paper suggests that altering the heat tolerance of corals through genetics could help delay the occurrence of high-frequency mass bleaching by up to 80 years.
Previous research also pointed out that heart tolerance generated by temporarily increasing the corals' resistance only delayed the onset of high-frequency bleaching by about 10 years.
Global warming has left large areas of coral reef severely damaged as the rise in sea water temperatures caused the corals to lose the symbiotic algae that help feed them. Many corals have died because of the ensuing mass bleaching, but some have been observed to survive even in elevated temperatures.
The recent study has helped scientists understand how certain corals are able to tolerate existing warmer waters.
AIMS evolutionary ecologist Line Bay said that the findings of their study can provide better insight as to how marine experts can help corals cope with hotter oceans.
The researchers said that reef-building corals similar to the ones used in the research can be collected from species endemic to the Caribbean Sea and the northern regions of the Pacific Ocean. Restoration and conservation efforts can be made in these areas in order to preserve heat-tolerant reefs and initiate the artificial propagation of corals.
The multi-organizational study is published in the journal Science.
Photo: Issy Witcomb | Flickr
