What is Blue Carbon?
As a result of human activities, carbon dioxide emissions are growing and changing the environment because CO2 traps heat from the sun onto the earth, which causes global warming. The increased accumulation of trapped atmospheric CO2 has many adverse affects on the environment, one of them is ocean acidification. When there are high levels of carbon in the atmosphere, it eventually accumulates in the ocean, forming carbonic acid. When there is too much carbonic acid in the water, the pH of the ocean decreases making the marine environment more acidic. The acidic environment consumes carbonate, a salt that is vital for marine life to form shells. Without this salt, marine life forms, such as coral reef building organisms to mussels and urchins, have a lower chance of survival.
However, coastal habitats such as seagrass beds, salt marshes and mangroves are able to absorb large quantities of carbon dioxide from the atmosphere and store it. Habitats that are able to absorb and store carbon are called carbon sinks; they contain carbon that has accumulated over hundreds of years. Blue Carbon refers to the carbon absorbed by coastal or marine organisms and stored in the habitat. The coastal habitats such as, sea grass beds, mangroves and salt marshes are able to sequester the carbon and store it. Plants can capture CO2 during photosynthesis, convert it to carbon-rich carbohydrates, use it to grow and when they die, part of the carbon in the plant is stored in the soil. Carbon is stored long-term in the plant materials or sediment. Studies have shown that coastal ecosystems like mangroves are some of the world’s most important carbon sinks. Mangroves and coastal wetlands annually sequester carbon at a rate two to four times greater than mature tropical forests and store three to five times more carbon per equivalent area than tropical forests. Unlike terrestrial ecosystems, most blue carbon is stored in the soil, not in the above ground plant material. The diagram above explains how carbon moves through the wetland ecosystem.
SeagrassNet looks to monitor and report on the global health of an important wetland ecosystem, seagrass beds. The program now includes 126 sites in 33 countries with a global monitoring protocol and web-based data reporting system. Seagrass beds help sequester carbon in wetlands, protect the coastline from storms and erosion and provide habitats for many important coastal organisms.