The objective of this study is to quantify the organic carbon (OC) storage and its sources in sediments of Dong Rui mangrove forests, Tien Yen district, Quang Ninh province by analyzing TOC (total organic carbon), TN (total nitrogen), C/N ratios, δ13C isotopes and sediment grain sizes. | Vietnam Journal of Earth Sciences, 38(4), 317-326, DOI: Vietnam Academy of Science and Technology Vietnam Journal of Earth Sciences (VAST) Quantifying organic carbon storage and sources in sediments of Dong Rui mangrove forests, Tien Yen district, Quang Ninh province using carbon stable isotope Pham Thao Nguyen, Nguyen Tai Tue*, Tran Dang Quy, Nguyen Dinh Thai Faculty of Geology, VNU University of Science Received 1 June 2016. Accepted 20 August 2016 ABSTRACT The objective of this study is to quantify the organic carbon (OC) storage and its sources in sediments of Dong Rui mangrove forests, Tien Yen district, Quang Ninh province by analyzing TOC (total organic carbon), TN (total nitrogen), C/N ratios, δ13C isotopes and sediment grain sizes. The results showed that the fine-grained sediment fraction (<63 µm) ranged from to ; TOC, TN contents, C/N ratios and δ13C values ranged from to , to , to and – to –‰, respectively. The variation of δ13C and C/N ratios, and the correlation between TOC, TN and the fine-grained sediment fractions indicated that mangrove forests play important roles in OC sequestration and accumulation of fine-grained sediments. The OC storage in sediments varied from to MgC ha-1 with an average of ± MgC ha-1. Nowadays, the mangrove forest area in Dong Rui is about ha, thus, the total OC in sediment pool up to 45 cm in depth, contained (±)×105 MgC, equivalent to (±)×105 Mg CO2. These results demonstrated that the conservation of Dong Rui mangrove forest not only provides opportunities for coastal protection and disaster mitigation and other provision values, but also enhancing carbon sequestration and offsetting greenhouse gas emissions. Keywords: mangrove forest, sediment, organic carbon, stable isotope, Dong Rui. ©2016 Vietnam Academy of Science and Technology 1. Introduction1 Mangrove .
