Biogenic hydrogen sulphide emissions and non-sea sulfate aerosols over the Indian Sundarban mangrove forest, D. Ganguly1,2 & R. Ray1,3 & N. Majumdar1 & C. Chowdhury1 & T. K. Jana1, Journal of Atmospheric Chemistry https://doi.org/10.1007/s10874-018-9382-3 Received: 16 November 2017 /Accepted: 2 November 2018/ # Springer Nature B.V. 2018 Abstract : Temporal variations in atmospheric hydrogen sulphide concentrations and its biosphere-atmosphere exchanges were studied in the World’s largest mangrove ecosystem, Sundarbans, India. The results were used to understand the possible contribution of H2S fluxes in the formation of atmospheric aerosol of different size classes (e.g. accumulation, nucleation and coarse mode). The mixing ratio of hydrogen sulphide (H2S) over the Sundarban mangrove atmosphere was found maximum during the post-monsoon season (October to January) with a mean value of 0.59 ± 0.02 ppb and the minimum during pre-monsoon (February to May) with a mean value of 0.26 ± 0.01 ppb. This forest acted as a perennial source of H2S and the sediment-air emission flux ranged between 1213 ± 276 μg S m−2 d−1(December) and 457 ± 114 μg S m−2 d−1 (August) with an annual mean of 768 ± 240 μg S m−2d−1. The total annual emissions of H2S from the Indian Sundarban were estimated to be 1.2 ± 0.6 Tg S. The accumulation mode of aerosols was found to be more enriched with non-sea salt sulfate with an average loading of 5.74 μg m−3 followed by the coarse mode (5.18 μg m−3) and nucleation mode (1.18 μg m−3). However, the relative contribution of Non-sea salt sulfate aerosol to total sulfate aerosol was highest in the nucleation mode (83%) followed by the accumulation (73%) and coarse mode (58%). Significant positive relations between H2S flux and different modes of NSS indicated the likely link between H2S, a dominant precursor for the non-sea salt sulfate, and non-sea sulfate aerosol particles. An increase in H2S emissions from the mangrove could result in an increase in enhanced NSS in aerosol and associated cloud albedo, and a decrease in the amount of incoming solar radiation reaching the Sundarban mangrove forest. Keywords Non-sea sulfate . H2S emission flux . Aerosol . Mangrove . Sundarban Journal of Atmospheric Chemistry https://doi.org/10.1007/s10874-018-9382-3 * D. Ganguly dipnarayan.ganguly@gmail.com 1 Department of Marine Science, University of Calcutta, 35, B.C. Road, Kolkata -700019, India 2 Present address: National Centre for Sustainable Coastal Management, MoEF&CC, New Delhi, India 3 Present address: Department of Chemical Oceanography, Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Japan

Phosphorus Budget of the Sundarban Mangrove Ecosystem: Box Model Approach R. Ray1,2 & N. Majumder1 & C. Chowdhury1 & S. Das1 & T. K. Jana1, Estuaries and Coasts (2018) 41:1036–1049 https://doi.org/10.1007/s12237-017-0332-0, Received: 26 March 2017 /Revised: 3 October 2017 /Accepted: 4 October 2017 # Coastal and Estuarine Research Federation 2017 Abstract: Phosphorus (P) cycling in mangroves plays an important role in productivity but the magnitude of atmospheric input in the mangrove P budget is still uncertain. This study applied a box model approach to assess P budget in the Indian Sundarban, the world’s largest mangrove ecosystem for conceptual understanding of P cycling and for better representation of transport and transformation of P within the mangrove ecosystem. The P content in the sediment (0.19–0.67 μg g−1) was found much below its maximum retention capacity (322 μg g−1) and was lower than the mean marine sediment (669 μg g−1). The C:N and C:P ratios were correlated (r2 = 0.66, P < 0.01) and the major fraction of available P was recycled within the organic structure of mangrove ecosystem, thus maintaining productivity through conservation strategies. Atmospheric input accounted for 56.7% of total P input (16.06 Gg year−1) and 50% of total P output (14.7 Gg year−1) was attributed to plant uptake. Budget closing or unaccounted P (1.36 Gg) was only 8.5% of the total input. Two feedback pathways, i.e., input of P from dust fallout and biochemical mineralization of organic matter, significantly affected P availability. The findings of the study suggest that atmospheric deposition is of major importance as a natural and/or anthropogenic forcing function in the Sundarban mangrove system. Keywords P budget . Biomass . Litter fall . Box model . Mangrove . Sundarban

Carbon sequestration by mangrove forest: One approach for managing carbon dioxide emission from coal-based power plant Raghab Ray∗, Tapan Kumar Jana Department of Marine Science, University of Calcutta, 35 B. C. Road, Kolkata, 700019, India, Atmospheric Environment 171 (2017) 149–154, A B S T R A C T Mangroves are known as natural carbon sinks, taking CO2 out of the atmosphere and store it in their biomass for many years. This study aimed to investigate the capacity of world's largest mangrove, the Sundarbans (Indian part) to sequester anthropogenic CO2 emitted from the proximate coal-based thermal power plant in Kolaghat (∼100 km away from mangrove site). Study also includes Kolkata, one of the largest metropolises of India (∼150 km away from mangrove site) for comparing micrometeorological parameters, biosphere-atmosphere CO2 exchange fluxes and atmospheric pollutants between three distinct environments: mangrove-power plantmetropolis. Hourly sampling of atmospheric CO2 in all three sites (late December 2011 and early January 2012) revealed that CO2 concentrations and emission fluxes were maximum around the power plant (360–621 ppmv, 5.6–56.7 mg m−2s−1 respectively) followed by the metropolis (383–459 ppmv, 3.8–20.4 mg m−2s−1 respectively) and mangroves (277–408 ppmv, −8.9–11.4 mg m−2s−1, respectively). Monthly coal consumption rates (41–57, in 104 ton month−1) were converted to CO2 suggesting that 2.83 Tg C was added to the atmosphere in 2011 for the generation of 7469732 MW energy from the power plant. Indian Sundarbans (4264 km2) sequestered total of 2.79 Tg C which was 0.64% of the annual fossil fuel emission from India in the same time period. Based on these data from 2010 to 2011, it is calculated that about 4328 km2 mangrove forest coverage is needed to sequester all CO2 emitted from the Kolaghat power plant., Keywords: Carbon dioxide Thermal power plant Mangrove Sundarban

Variation of Carbon Sequestration in Relation to Leaf Level RNA:DNA In Sundarban Mangrove, India Review Article, Majumder N, Chowdhury C, Jana TK* Department of Marine Science, Calcutta University, Kolkata, India, International Journal of Marine Science and Ocean Technology, 3(4), 33-39. Abstract: Mangrove productivity varies in space and time depending on community structure, phenology, resource availability and salinity stress. In Indian Sundarbans, mangrove species with different growth rate sequester significant amount of carbon. This study reports the applicability of using leaf level RNA:DNA ratios for assessing intraspecific and interspecific differences in carbon sequestration of four mangrove species under field condition. It was observed that DNA concentration in mangrove leaves varied within a relatively narrow range, and higher variations in RNA could indicate its direct implication in protein synthesis, which in turn was strongly dependent on environmental condition such as nitrogen (N) and phosphorus (P) availability and salinity stress. Leaf level RNA:DNA ratio in mangrove could be a good indicator of carbon sequestration and mangrove could maintain high carbon sequestration rate under nutrient limited condition through nutrient conservation strategies. Keywords: Nucleic Acids; Growth Rate; Nutrients; Eco Stoichiometry; Salt Tolerant Plants.

Effect of pH and Salinity on Sorption of Antimony (III and V) on Mangrove Sediment, Sundarban, India Sanjay Kumar Mandala, Natasha Majumderb, Chumki Chowdhuryb, Tapan Kumar Janab, and Buddhadeb Duttac aDepartment of Chemistry, Calcutta University, Sundarban Hazi Desarat College, Pathankhali, 24 Pgs (South), West Bengal, India; bDepartment of Marine Science, Calcutta University, 35, B. C. Road, Kolkata, India; cDepartment of Chemistry, West Bengal State University, Ramakrishna Mission Vivekananda Centenary College, Rahara, Kolkata, India,SOIL AND SEDIMENT CONTAMINATION 2017, VOL. 26, NO. 7, 1–12 https://doi.org/10.1080/15320383.2017.1400519, ABSTRACT The extent of toxic metalloid retention and bioavailability and mobility in the sediment is of interest for understanding their biogeochemical cycling and for accurate risk assessment in an ecosystem. Intensification of monsoon and rainfall, believed to be related to global warming, could drive future changes of temperature, salinity, and pH distribution pattern affecting antimony cycling in the Sundarbans. This study investigated sorption kinetics of antimony (Sb) (III and V) as a function of temperature, salinity, and pH following the Langmuir model, and demonstrated that clayey silt type mangrove sediment was an effective adsorbent with higher efficiency for Sb (V) than Sb (III). Background level of Sb in the sediment was 0.35–0.78% of the maximum adsorption capacity (Gm). Out of the two distinct type of sorption sites governing mobility and bioavailability of Sb in the sediment, site 1 (Humic acid) showed higher affinity for Sb than the site II (oxyhydroxide). Sb adsorption was strongly influenced by temperature, salinity, and pH, which may be altered by long-term changes in climate and rainfall pattern. KEYWORDS Antimony; mangrove sediment; pH; salinity; sorption

Distribution, sources and biogeochemistry of organic matter in a mangrove dominated estuarine system (Indian Sundarbans) during the pre-monsoon R. Ray a, *, T. Rixen a, A. Baum a, A. Malik b, G. Gleixner b, T.K. Jana c a Department of Biogeochemistry, Leibniz Center for Tropical Marine Ecology, 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, IndiaEstuarine, Coastal and Shelf Science xxx (2015) 1-10, journal homepage: www.elsevier.com/locate/ecss, a r t i c l e i n f o Article history: Received 12 February 2015 Received in revised form 29 September 2015 Accepted 16 October 2015 Available online xxx Keywords: Organic and inorganic carbon Stable isotopes (C, N) Sundarbans a b s t r a c t The sources and distribution of dissolved organic carbon (DOC), particulate organic carbon (POC) and dissolved inorganic carbon (DIC) in the Indian Sundarbans mangrove and Hooghly estuarine system were examined during the pre-monsoon (summer) 2014. DOC is the dominant form of organic matter (OM) in the studied estuarine waters and represents a mixture of mangrove and riverine sources. Microbial degradation of land derived OM results in a high pCO2 in the Hooghly estuarine waters while enrichment in d13C-DIC ascribes to CO2 uptake by phytoplankton in the Sundarbans water. Higher d15N in the particulate organic nitrogen (PON) of the mangrove and marine zone could be associated with enhanced phytoplankton production sustained by nitrate from mangrove derived OM decomposition and/or nitrate imported from the Bay of Bengal. Low organic carbon contents and elemental ratios (TN/TOC) indicate an intense mineralization and transformation of OM in the sediments, resulting insignificantly different OM compositions compared to those of the three major sources: land derived OM, mangrove leaf litter (Avicennia marina) and in situ phytoplankton production. © 2015 Elsevier Ltd. All rights reserved.

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