Researchers in the US have developed a model that can predict which mangrove soils contain the most carbon. The hope is that the model will encourage the formation of a carbon market for mangroves, which are known to store much more carbon on average than other types of vegetation.
Studies suggest that mangroves contain three to four times the amount of carbon in boreal, temperate or upland-tropical forests. Unlike these forest ecosystems, mangroves store most – about 70% – of their carbon in soil, which steadily collects organic matter dumped by tides. Since this matter is stored underwater, it decomposes anaerobically, helping it to retain the carbon.
With such extensive reserves of carbon, mangroves are a prime target for those who want to prevent the release of greenhouse gases. Unfortunately, mangroves are also a target for developers, who view the swampy ground as ideal for highly profitable shrimp or rice farms. Even if farming is not a threat, urban development may be, and the pollution generated by towns and cities can take an additional toll. A loss of mangroves means a loss of all the carbon stored up over hundreds of years or more – and a loss, too, of the habitats of the wildlife that they support.
“These ecosystem services generally have no market value; so keeping mangroves as mangroves may not offer economic compensation to whoever is managing the land, even though that manager is providing a valuable service,” said Sunny Jardine of the University of Delaware, US. A solution to this problem, according to Jardine, is the creation of “missing markets” for mangrove ecosystem services, similar to those made for forests through the United Nations’ REDD (reduced emissions from deforestation and forest degradation) programmes.
By JON CARTWRIGHT