What is blue carbon and coastal blue carbon ecosystems? Green plants on land can fix carbon dioxide in the air through photosynthesis, which is called "green carbon". Compared with "green carbon" on land, in the vast ocean, the process, activities and mechanisms that use marine a

What is blue carbon and coastal blue carbon ecosystems?
Green plants on land can fix carbon dioxide in the air through photosynthesis, which is called "green carbon" . Compared with "green carbon" on land, in the vast ocean, the process, activities and mechanisms that use marine activities and marine organisms to absorb carbon dioxide in the atmosphere and fix and store it in the ocean are called "blue carbon" .

The concept of "blue carbon" comes from the "Blue Carbon" jointly issued by the United Nations Environment Program (UNEP), the Food and Agriculture Organization of the United Nations (FAO) and the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization (IOC-UNESCO) in 2009. : Assessment Report on Carbon Sequestration in Healthy Oceans" (referred to as "Blue Carbon Report"), which specifically refers to carbon fixed in marine ecosystems such as mangroves, salt marshes and seagrass beds. These coastal ecosystems that can sequester and store carbon are called "coastal blue carbon ecosystems". Their representatives - mangroves, seagrass beds and coastal salt marshes are also called "the three major coastal blue carbon ecosystems". Ecosystem" .

What kind of “superpowers” ​​does the coastal blue carbon ecosystem

have?

What are the advantages of

"blue carbon" compared to "green carbon" on land?

What are the prospects and significance of my country’s development of blue carbon?

The important role of coastal blue carbon ecosystems

Small "body", large reserves

01 The ocean stores about 93% of the carbon dioxide on the earth, which is estimated to be about 40 trillion tons, making it the largest carbon pool on the earth. 02 The ocean can remove more than 30% of the carbon dioxide emitted into the atmosphere every year. It plays a vital role in reducing atmospheric CO₂ and mitigating global climate warming . It is also a feasible path besides "emission reduction". 03 Mangroves, seagrass beds and salt marshes, as the three major coastal blue carbon ecosystems, can capture and store large amounts of carbon and have extremely high carbon sequestration efficiency. 04 Although the coverage area of ​​these three types of ecosystems is less than 0.5% of the seabed , and the plant biomass only accounts for 0.05% of the terrestrial plant biomass, their carbon reserves are as high as more than 50% of the ocean's carbon reserves, and may even be As high as 71%! According to statistics, the annual carbon burial amount of coastal blue carbon ecosystems, including estuaries and offshore continental shelves, is 237.6 million tons of carbon per year, which is much higher than the carbon burial rate in the deep sea; the carbon burial rate per unit area of ​​these ecosystems They are 4.5, 3.0 and 4.8 times that of terrestrial temperate forests, tropical forests and boreal forests respectively.

For example, in North Carolina, USA, the annual carbon storage volume of a coastal salt marsh wetland with an area of ​​only 0.25km² is equivalent to the carbon dioxide emitted by burning 28,000 liters of gasoline. It can be said that it is a small body with large reserves.

has good "sealing" and can accumulate for a long time

01

Specifically, the carbon of the coastal blue carbon ecosystem is stored in the soil of mangroves, salt marshes and seagrass beds, above-ground living matter (leaves, branches, stems), underground living matter in matter (roots) and in non-living biomass (such as litter and dead wood). Like carbon stored in terrestrial ecosystems, blue carbon is carbon fixed by living plants over a relatively short period of time (years to decades).

02

Different from the carbon saturation phenomenon in terrestrial ecosystems, the carbon fixed in the soil of coastal ecosystems can be buried over a wide range and for a long time, thus forming huge carbon reserves.

03

The difference between coastal ecosystems and terrestrial ecosystems is also reflected in the potential soil carbon accumulation: terrestrial soil is rich in oxygen , which enables aerobic microorganisms to oxidize carbon in the soil and return it to the atmosphere; but coastal blue carbon ecosystems The saturated soil water environment keeps the soil in an anaerobic state (or almost oxygen-free), thereby continuing to store carbon in the vertical direction.

04

For example, the Posidonia oceanica seagrass bed in Port Lligat Bay, Spain, and the 6,000-year-old, ten-meter-thick mangrove sediments in Brazil are both huge sediment carbon reservoirs; New England The tidal salt marshes in the north are also very typical, with a thickness of up to 3 to 5 meters, a history of three to four thousand years, and an organic carbon content of more than 40%.

functions far more than carbon sequestration and storage

01

In addition to its powerful carbon sink capacity for carbon sequestration and storage, coastal blue carbon ecosystems are equally significant to human well-being and global biodiversity.

02

For example, coastal blue carbon ecosystems such as mangroves, seagrass beds, and salt marshes protect coastal zones by slowing coastal erosion and protecting shorelines. After Typhoon Haiyan, as well as other destructive cyclones and hurricanes, the importance of coastal blue carbon ecosystems has been widely recognized.

03

Coastal blue carbon ecosystems not only regulate water quality, provide important habitats for fish and shellfish, and provide wood for humans, but are also the habitat for many endangered and rare species. They are also a source of nutrients for neighboring ecosystems and are important economic species. Provide living space while having aesthetic and eco-tourism functions.

[Looking for Fishing, bringing the ocean into life]