A Bright Side for Coral Reefs?

This coral crab (Trapezia rufopunctata) hangs out in Walindi, West New Britain, Papua New Guinea. The country is home to some of the "bright spots" among the world's coral reefs. AGG/Contributor/Universal Images Group/Getty

Coral reefs are amazing. They cover less than 2 percent of the ocean floor and yet support 25 percent of all marine creatures. But they've had a rough go of it over the last few decades. 

Climate change, pollution, fishing and other stressors have damaged these delicate ecosystems and raised the possibility of a massive decrease in marine biodiversity. But there's a glimmer of hope, thanks to a recent research project.

The research letter, published in Nature, describes "bright spots" in coral reefs. These areas have healthier ecosystems than we would expect, given environmental conditions. And they also might give us hints as to how we can better conserve other coral reef ecosystems around the world.

The researchers looked at data from more than 2,000 coral reefs in 46 countries. They identified 18 factors that affect coral reef health, from environmental variables to socioeconomic drivers. Some of those factors include whether or not the reef is openly fished, the popularity of the site among tourists and the physical features of the ocean floor. The researchers looked for outliers: reefs that either were doing much better than would be expected or much worse.

The letter identifies 15 bright spots, each of which has a biomass level at least two standard deviations from what was expected. And while you might think these coral reefs must be located in remote areas far from human populations, that wasn't entirely the case. For example, Indonesia and Papua New Guinea both are home to bright spots.

They also identified 35 dark spots, or reefs doing more poorly than expected. These included reefs off the coast of Hawaii as well as the Great Barrier Reef in Australia.

So which factors were most important? The researchers said "market gravity" had the biggest impact. Essentially, reef biomass goes down in areas where markets are large and easily accessible. It's not quite that simple, though. The researchers also saw that reefs bordering wealthy nations tend to be in better condition than those that don't.

While the researchers suggest some general approaches to improve conservation efforts for reefs in danger, they stress that more study is required to get a full understanding of what contributes to the success of the bright spots. Preliminary suggestions include creating legal policies that govern fishing practices and designing sustainable harvesting certifications. And they also point out that a global reduction in carbon emissions is ultimately necessary to preserve coral reefs.

It's not going to be easy, but the bright spots are proof that there are measures we can take to reduce or even reverse the decline of coral reefs around the world. It may not be as gloomy as we thought.