Blue carbon refers to carbon stored in coastal and marine ecosystems, including wetlands, kelp forests, mangrove forests, seagrass, and coral reefs. Commonly known as blue carbon ecosystems, they sequester and store large quantities of blue carbon in both the plants and the sediment below.
Blue carbon ecosystems are found on every continent except Antarctica. SeaTrees develops coastal restoration projects across five blue carbon ecosystem types: mangrove forests, kelp forests, seagrass meadows, coral reefs, and coastal watersheds.
Kelp can sequester ~200 million tons of carbon dioxide per year by absorbing CO2 from both the atmosphere and the ocean and exporting large portion of its biomass out into the deep sea, sinking it to the deep ocean permanently. Each year 10% of kelp primary productivity is permanently sequestered.
Coral reefs are home to 25% of all marine life in the ocean and are the most diverse marine ecosystem on earth. Coral can sequester huge amounts of carbon from dissolved CO as carbonate - so that carbon stays within in the reef system and out of the ocean and atmosphere.
Seagrasses are being lost at a rate of 1.5% per year. They cover less than 0.2% of ocean floor, but store about ~10% of the carbon buried in ocean sediment each year.
Blue carbon ecosystems are most effective when they are directly connected to a healthy watershed, which can capture and store atmospheric CO2 at 10x the rate of a mature tropical forest by sequestering it in the ground for many years.