A senior expert called for intensified efforts to protect ecosystems in coastal waters because of their significant ability to absorb carbon while speaking at forum on Wednesday, which is also World Oceans Day.

Covering about 71 percent of the Earth's surface, the ocean holds about 40 trillion metric tons of carbon — about 50 times more than in the air, said Zhou Hongchun, a researcher at the Development Research Center of the State Council, at a forum organized by the All-China Environment Federation.

He noted the strong capabilities of three coastal ecosystems in soaking up carbon — mangrove forests, sea grass beds and salt marshes. Occupying only 0.5 percent of the seabed, they soak up more than half the carbon the ocean holds.

Mangrove forests, for example, only cover 0.5 percent of the world's coastal areas. In the sediment held by mangrove trees, however, the content of carbon reaches 10 to 15 percent.

"The tree is a master of capturing blue carbon," Zhou noted.

Blue carbon refers to the carbon stored in coastal and marine ecosystems.

From this point of view, marine management authorities should make efforts to promote ecosystem restoration and conservation in coastal areas, he stressed.

World Oceans Day is celebrated annually on June 8.