Estimation of carbon pools in the biomass and soil of mangrove forests in Sirik Azini creek, Hormozgan province (Iran)

Despite the increasing interest in mangroves as one of the most carbon-rich ecosystems, arid mangroves are still poorly investigated. We aimed to improve the knowledge of biomass and soil carbon sequestration for an arid mangrove forest located at the Azini creek, Sirik, Hormozgan Province (Iran). We investigated the biomass and organic carbon stored in the above and belowground biomass for three different regions selected based on the composition of the principal species: (1) Avicennia marina, (2) mixed forest of A. marina and Rhizophora mucronata, and (3) R. mucronata. Topsoil organic carbon storage to 30 cm depth was also estimated for each analyzed area. Biomass carbon storage, considering both aboveground (AGB) and belowground biomass (BGB), was significantly different between the cover areas. Overall, the mean forest biomass (MFB) was 283.1 ± 89 Mg C ha−1 with a mean C stored in the biomass of 128.9 ± 59 Mg C ha−1. Although pure Rhizophora stand showed the lowest value of above and below tree carbon (AGC + BGC); 17.6 ± 1.9 Mg C ha−1), soil organic carbon stock in sites under Rhizophora spp. was significantly higher than in the site with pure stand of Avicennia spp. Overall, forest soil stored the highest proportion of Sirik mangrove ecosystem organic carbon (59%), with a mean value of 188.3 ± 27 Mg C ha−1. These results will contribute to broaden the knowledge and the dataset available, reducing the uncertainties related to estimates and modeling of carbon pools in arid mangrove ecosystem, which also represent an important climatic threshold of mangrove worldwide distribution.