Oceans and coastal ecosystems, including mangroves, seagrasses, and salt marshes, capture and store carbon. Salt marshes and mangrove forests are particularly good at sequestering carbon because in addition to holding carbon in the living plant matter (as all plants do), they retain dead plant matter which capture carbon within sediments built up over time. Because of this, these systems are capable of burying large amounts of carbon over a long time period if the ecosystems remain stable.

Carbon sequestration in freshwater ecosystems is more complicated as they are often a carbon sink; however, freshwater marshes can, at times, emit methane, another powerful greenhouse gas.

The fresh water we use comes from beneath the Earth’s surface (groundwater) or from lakes and rivers. Aside from clean water, healthy watersheds provide climate regulation and healthy soils.

Protecting all of these systems is crucial, as they play a significant role in habitat conservation and ecological resiliency. They can also become a source of carbon emissions (emitting huge amounts of carbon back into the atmosphere) when they are damaged.

The Northeast Carbon Alliance has formed a water systems working group to define the relationships between various water systems with respect to how carbon is sequestered or released, where knowledge gaps exist, and what role Blue Carbon could play in the preservation of these valuable natural ecosystems.