Coastal seagrass can store more heat-trapping carbon per square mile (kilmometre) than forests can, which means these coastal plants could be part of the solution to climate change, scientists said in a new study.

Even though seagrasses occupy less than 0.2 percent of the world's oceans, they can hold up to 83,000 metric tons of carbon per square kilometer, a global team of researchers reported Sunday in the journal Nature Geoscience.

That is more than twice the 30,000 metric tons of carbon per square kilometer a typical terrestrial forest can store.

Earth's oceans are an important carbon sink - keeping climate-warming carbon dioxide from human-made and natural sources out of the atmosphere - and seagrasses account for more than 10 percent of all the carbon buried in oceans each year, the scientists found.