Estimating blue carbon storage in the mangrove forest of Gaz-Harra wetland, Strait of Hormoz

Abstract

Mangrove forests efficiently absorb and fix carbon ecosystems, playing an influential role in reducing greenhouse gases. In this study, we measured the whole and top 1 m soil carbon (C) stock and the carbon stored in the above- and belowground parts of mangroves in 10 stations within the Gaz-Hara Wetland (GHW). GIS-based satellite image processing indicated that the total area of the GHW mangrove forest is 1038 ha, and Rizophora mucronata, mixed, high-density Avicennia marina, and low-density A. marina habitats comprise 12.5, 30, 35.5 and 22% of the forest area, respectively. Soil organic C content ranged from 0.45–3.01%, with A. marina habitats having a higher content than the R. mucronata habitats. The average top 1 m soil C stock of mangrove is 108 MgC ha−1, with high-density A. marina habitat accounting for 37% of it. This amount is within the global average range of mangroves in dry subtropical areas. The total amount of soil C stock in the area is 220,867 MgC. Furthermore, 361,000 MgC has been sequestered in the mangrove trees of GHW, 69% of which is accumulated in the aboveground and the rest in the belowground portions. The soil and trees of the GHW habitats have stored 537 Gg C, equivalent to 1.97 Tg CO2, of which 220 and 317 Gg C have been accumulated in the soil and the biomass of mangrove trees, respectively. Deforestation of GHW mangroves would result in a potential CO2 emission of 1.33 Tg CO2 (1.16 Tg CO2 by trees and 0.17 Tg CO2 by the top 1 m of soil).