What is blue carbon?

The correct answer is: Carbon captured by oceans and coastal ecosystems.

Explanation:

Blue carbon refers to the carbon dioxide captured from the atmosphere and oceans, and subsequently stored by marine and coastal ecosystems. These ecosystems include seagrass meadows, tidal marshes, and mangrove forests.

Coastal and marine ecosystems act as major carbon sinks because they sequester and store carbon at much higher rates per unit area than terrestrial forests, storing it primarily in their soils and sediments for long periods.