The planet’s seagrass meadows store more than twice as much carbon per square kilometer as forests, demonstrating that coastal vegetation can play an important role in mitigating climate change, a new study says. Writing in the journal Nature Geoscience, a team of scientists calculated that coastal seagrass beds can store up to 83,000 metric tons of carbon per square kilometer, compared with 30,000 metric tons of carbon per square kilometer in typical forests. While seagrasses occupy less than 0.2 percent of the world’s oceans, they account for more than 10 percent of all the carbon trapped in the sea.Seagrasses have a unique ability to store carbon in their roots and soil in coastal areas, the study showed. In some regions, they found, seagrass beds have stored carbon for thousands of years. “Seagrasses only take up a small percentage of global coastal area, but this assessment shows that they’re a dynamic ecosystem for carbon transformation,” said James Fourqurean, a scientist at Florida International University and lead author of the study.