Exportation of dissolved (inorganic and organic) and particulate carbon from mangroves and its implication to the carbon budget in the Indian Sundarbans R. Ray a,⁎, A. Bauma, T. Rixena, G. Gleixner b, T.K. Jana c a Department of Biogeochemistry, Leibniz Center for Tropical Marine Research; Fahrenheitstr. 6, 28359 Bremen, Germany b Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Hans Knoell Str. 10, 07745 Jena, Germany c Department of Marine Science, University of Calcutta, 35 B. C. Road, Kolkata 700019, India, Science of the Total Environment 621 (2018) 535–547, a b s t r a c t Article history: Received 24 August 2017 Received in revised form 19 November 2017 Accepted 20 November 2017 Available online xxxx Editor: G. Ashanta Goonetilleke Mangroves are known for exchanging organic and inorganic carbon with estuaries and oceans but studies that have estimated their contribution to the global budget are limited to a few mangrove ecosystems which exclude world's largest the Sundarbans. Here, we worked in the Indian Sundarbans and in the Hooghly river/estuary in May (pre-monsoon) and December (post-monsoon), 2014. Aims were, i) to quantify the riverine export of particulate organic carbon (POC) and dissolved organic and inorganic carbon (DOC, DIC)) of the Hooghly into the Bay of Bengal (BoB), ii) to estimate the C export (DOC, DIC, POC) from the Sundarbans into the BoB by using a simple mixing model, as well as iii) to revise the existing C budget constructed for the mangroves. The riverine exports of POC, DOC and DIC account for 0.07 Tg C yr−1, 0.34 Tg C yr−1 and 4.14 Tg C yr−1, respectively, and were largest during the monsoon period. Results revealed that mangrove plant derived organic matter and its subsequent degradation is the primary source of DIC and DOC in the Hooghly estuary whereas POC is linked to soil erosion. Mangroves are identified as a major source of carbon (POC, DOC, DIC) transported from the Sundarbans into the BoB, with export rates of 0.58 Tg C yr−1, 3.03 Tg C yr−1, and 3.69 Tg C yr−1 respectively, altogether amounting to 7.3 Tg C yr−1. This C export from the Indian Sundarbans exceeds the ‘missing C’ of the previous budget, thus necessitating further research to finally resolve the mangrove C budget. However, these first baseline data on C exports fromthe world's largest deltaic mangrove improves limited global data inventory and signifies the need of acquiring more data from different mangrove settings to reduce uncertainties. © 2017 Elsevier B.V. All rights reserved