What is blue carbon?

1. The term 'blue carbon' refers to the carbon stored in marine and coastal ecosystems. 2. Option (A) correctly defines blue carbon as carbon captured by oceans and coastal ecosystems like mangroves, seagrasses, and tidal marshes. These ecosystems are highly effective at sequestering carbon dioxide from the atmosphere and storing it in their biomass and sediments. 3. Option (B) describes 'green carbon', which is carbon sequestered in terrestrial ecosystems such as forest biomass and soils. 4. Option (C) refers to fossil fuels (petroleum, natural gas), which contain carbon but are not part of the active biological carbon cycle captured by the term blue carbon. 5. Option (D) refers to atmospheric carbon, which is the source pool, not the sequestered carbon in specific ecosystems.