# Seasonal Variations of Carbon Dioxide, Water Vapor and Energy Fluxes in Tropical Indian Mangroves  
[PERSON]  
1 National Remote Sensing Centre (I.S.R.O), Balanagar, Hyderabad PIN 500 037, India;  
[EMAIL_ADDRESS] (K.C.T. ); [EMAIL_ADDRESS] (C.S.J. ); [EMAIL_ADDRESS] (V.K.D.) 1  
[PERSON]  
National Remote Sensing Centre (I.S.R.O), Balanagar, Hyderabad PIN 500 037, India;  
[EMAIL_ADDRESS] (K.C.T. ); [EMAIL_ADDRESS] (C.S.J. ); [EMAIL_ADDRESS] (V.K.D.) 1  
[PERSON] and [PERSON]  
1 National Remote Sensing Centre (I.S.R.O), Balanagar, Hyderabad PIN 500 037, India;  
[EMAIL_ADDRESS] (K.C.T. ); [EMAIL_ADDRESS] (C.S.J. ); [EMAIL_ADDRESS] (V.K.D.) 1  
Footnote 1: email: : +9140-2388-4219; Fax: +9140-2387-5932  
Footnote 2: email: : +9140-2388-4219; Fax: +9140-2387-5932  
Footnote 3: email: : +914  
In the tropics, mangroves are the most carbon-rich forests with an average estimate of 1023 Mg C h\({}^{-1}\)[5] and high rates of primary production estimated at 218 \(\pm\) 72 Tg C year\({}^{-1}\) globally [6]. Thus, due to their tropical distribution [7; 8] and rich biogeochemistry [9; 10], they are one of the important terrestrial ecosystem at the interface of land and ocean to be understood. Measurements of CO\({}_{2}\) fluxes between forests and atmosphere are important to understand their response to climate change and predict the vegetation feedback to the climate system [4]. Eddy covariance (EC) is the most direct way to measure the exchange rate of CO\({}_{2}\) across the soil and vegetation-atmosphere interface at scales of \(\sim\)1 km\({}^{2}\) using micrometeorological theory for different time scales, ranging from hours to years [11; 12; 13; 14]. The net ecosystem exchange (NEE), defined as the net CO\({}_{2}\) exchange between the ecosystem and the atmosphere, is generally approximated by net ecosystem productivity (NEP) as well in many terrestrial ecosystems (NEE = \(-\)NEP) over short time periods [13]. The EC method is most widely used method to measure CO\({}_{2}\) fluxes in over 400 flux research sites in FLUXNET (global flux network) which assimilates information from these sites over a wide range of biomes [15]. Though the importance of mangrove ecosystems in the global carbon budget is significant, limited information exists on the carbon assimilation capacity of mangroves [16]. The oft-reported flux tower in mangroves was established in the coastal Florida Everglades in 2003. Results suggested that everglade mangroves are a carbon sink that had an annual NEP of 1170 \(\pm\) 127 g C m\({}^{-2}\). year\({}^{-1}\) during 2004 [17]. Sundarbans mangroves are the largest continuous stretch of mangrove forests in the world, covering about 10,000 km\({}^{2}\) (_i.e._, nearly 6%-7%) of the global mangrove area (15 \(\times\) 10\({}^{4}\) km\({}^{2}\)) spreading over India and Bangladesh [18]. To understand and estimate the source and sink strengths of these mangroves, few studies have been carried out in selected locations of the Sundarbans deltaic system. The studies using the micrometeorological gradient technique has revealed that the ecosystem was a CO\({}_{2}\) sink. [PERSON] _et al._ had observed the environment of Jambu Island (southwest corner of Indian Sundarbans) to be a sink for CO\({}_{2}\) in the pre-monsoon season at a rate of \(-\)56.5 g CO\({}_{2}\) m\({}^{-2}\). day\({}^{-1}\)[19]. [PERSON] _et al._ have reported a mean net flux of \(-\)48.3 g CO\({}_{2}\) m\({}^{-2}\). day\({}^{-1}\) at the same Lothian Island and Sajnekhali, and have also estimated a total sink strength of 205 Gg: day\({}^{-1}\) for entire reserve forest areas (4264 km\({}^{2}\)) [20]. During 2011-2012, a series of experiments using micrometeorological measurements were carried out by [PERSON] _et al._ in Sundarbans mangroves at different stations _viz._ Jharkhali, Henry Island and Bonnie Camp to understand the spatial variability of CO\({}_{2}\) flux [21]. They have reported that the ecosystem is a sink for CO\({}_{2}\) during the daytime with varying fluxes between \(-\)33.69 to \(-\)114.91 g CO\({}_{2}\) m\({}^{-2}\).