Blue carbon is the term that refers to the carbon captured by the oceans and coastal ecosystems. Coastal blue-carbon ecosystems, especially mangroves, seagrass, saltmarshes and those with marine algal communities, sequester and store large amounts of carbon in their plants (or plant-like structures), roots and soil, which makes them an important carbon sink.

Protection and restoration of these coastal blue-carbon ecosystems is crucial due to the many benefits they provide to wildlife and local communities and economies. These benefits are associated with ecological functions and ecosystem services, which include habitat, food, medicine, water quality, storm surge protection, climate change mitigation and beauty.