That 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% 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% of all the carbon buried in oceans each year, the scientists found.  

Led by James Fourqurean of Florida International University, the study included participants from Virginia, Spain, Australia, the United Kingdom, Denmark and Greece.  

“Seagrasses have the unique ability to continue to store carbon in their roots and soil in coastal seas,” Fourqurean said in a statement. “We found instances where particularly seagrass beds have been storing carbon for thousands of years.”  

In addition to storing carbon, seagrasses filter out sediment before it gets into oceans, protect coastlines from floods and storms and serve as habitat for fish, crustaceans and other commercially important species.  

Seagrasses can be damaged by human activity, such as pollution from oil spills and by boat propellers and cargo that can rake through seagrass meadows and cut through roots.  

Some of the study’s authors are affiliated with the Blue Carbon Initiative, a global plan to mitigate climate change by conserving and restoring coastal marine ecosystems. The initiative is a collaboration between UNESCO, the International Union for Conservation of Nature and Conservation International.