Conservationists are working hard to save the Great Barrier Reef.

Diagnoses of its health have gone from bad to dire to critical. The reef system, a world wonder and habitat for thousands of species, often falls prey to invasive starfish, but one of the reef system's biggest threats is coral bleaching.

Now, a team of researchers think they may have a solution to bandage one of the Great Barrier Reef's more serious wounds.

A "sun shield" 50,000 times thinner than a human hair has been designed to sit at the surface of the water, directly above corals. The thin film is meant to be like an umbrella that partially blocks out the sun. The shield is biodegradable and is made of calcium carbonate, the same component that coral skeletons are made of.

The project, created by the University of Melbourne and the Australian Institute of Marine Science, was recently announced by the Great Barrier Reef Foundation.

So far, the shield has been only tested in a lab. According to a press release from the Great Barrier Reef Foundation, the film could block out as much as 30 percent of the sunlight penetrating the corals.

Shielded from sunlight, scientists think corals may be able to mitigate coral bleaching events. The term refers to the process in which corals expel the symbiotic algae that live inside their tissues, and which normally share food with the corals. After losing their algae, the corals turn completely white. If conditions improve, they can recover the algae and thus their health. But if they are bleached too long they starve and die. The process is brought on by pollution or too much light or warmth.

In 2005, a spate of warm weather killed off half of the U.S.'s corals. Two thirds of the Great Barrier Reef have fallen prey to the condition over the past few years.

Spot Solution?

"The surface film provided protection and reduced the level of bleaching in most [coral] species," Anna Marsden from the Great Barrier Reef Foundation said in a statement.

"It's important to note that this is not intended to be a solution that can be applied over the whole 348,000 square kilometers of Great Barrier Reef—that would never be practical," she added. "But it could be deployed on a smaller, local level to protect high-value or high-risk areas of reef."

Race Against Time

Australia is desperately searching for solutions to fight against the Great Barrier Reef's decline.

At the beginning of this year, an analysis published in the journal Science found the window to save the Great Barrier Reef is rapidly closing. The analysis confirmed that bleaching events were happening more frequently, giving corals less time to recover from a stressful episode.

Several days after the report was published, the Australian government announced they had set aside 1.6 million US dollars for funding projects. Included was a cash prize to whomever offers a clever solution to save the reef.

In 2013, the commonwealth set aside more than nine million US dollars to fund a four-year research program called Resilient Coral Reefs Successfully Adapting to Climate Change. The program in part supported the sun shield, along with additional private donations.

More testing will be needed before researchers can deploy the film outside the lab.