Nature has blessed humans in many ways, initiating from providing life to creating life-supporting systems to enrich it. These life-supporting systems may be air, water, soil to name a few, and are not limited up to providing food, shelter, and pleasure but also acts as a powerful tool in rescuing humans from inevitable events.
Everything nature has provided is enclosed in a loop, and so the carbon. It is present in both living and non-living things. Usually, the plant cell is made up of carbon. Also, during photosynthesis, it pulls a certain amount of carbon from the atmosphere, which ultimately gets buried into the soil by their (plant) death. In non-living things such as rocks, it is present in the combined form such as calcium carbonate, sodium carbonate, etc., and in coal, its amount is tremendous and hence is known as black carbon.
The other type of carbon other than black carbon is blue carbon and is related to living things. It includes mostly mangroves and sea-grasses, salt marshes, macro-algae through the accumulation of carbon and burial into the soil. These are some of the useful sources for removing the dominant greenhouse gas (carbon dioxide) from the atmosphere through the process of carbon sequestration.
Mangroves are small shrubs or trees that grow in the coastal saline or brackish water as they are highly productive along oceans and tidal estuaries. They are found mostly in tropical and sub-tropical climatic zones because they are irresistible to colder zones. One of the characteristics of mangroves is they are susceptible to floods, high tidal waves, or winds preventing surrounding areas from destructions. They provide home and breeding grounds to millions of plant and animal species. The special characteristics are that they store carbon deep in their roots and in the soil below. Worldwide, it is spread across 18.1 million hectares of an area, the largest population present in the Indo-West Pacific region, approximately 45.1% of total world forests. In India, West Bengal has the highest mangroves, followed by Gujarat.
The two types of mangroves are red and black mangroves. The red mangroves belong to Rhizophora species and withstand better in brackish and marine water bodies. The black mangroves belong to Avicennia species; grow well near the land side of estuaries. The oxygen-consuming capacity of mangroves depends on their species.
In recent decades, due to construction and development even along the coastlines, the mangrove density has been drastically reduced, as they are widely used to build accommodation for tourists. The mangroves capture and store high carbon in comparison to terrestrial trees. Hence their destruction could lead to the release of a considerable amount of carbon back into the atmosphere. Some commonly known mangrove species are Avicennia nitida (black mangrove), Avicennia marina (tivar), Azadirachta indica (neem tree) which act as a significant carbon sequester. It is estimated that mangroves sequester approximately 25.5 million tons of carbon every year, which is roughly equal to diesel used by a car per year. Almost 225,000 metric tons of carbon sequestration potential are lost each year with current rates of mangrove destruction. Disturbed mangrove soils release greater than an additional 11 million metric tons of carbon annually.
Mangroves play a major role not only as carbon sequester but also act as a barrier protecting millions of lives from floods and storms. Thus, their protection and conservation have become a global challenge to alleviate the issue of global warming and climate change. Currently, the Government has protected these areas as Eco-Sensitive Areas, Coastal Regulatory Zone, where entry of persons and construction activities are prohibited. Destruction of mangroves harms not only humans but also animal species residing there. The awareness related to different mangrove species should be disseminated to maximize their population.