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Journal ArticleDOI

Impact of Sundarban mangrove biosphere on the carbon dioxide and methane mixing ratios at the NE Coast of Bay of Bengal, India

01 Feb 2002-Atmospheric Environment (Pergamon)-Vol. 36, Iss: 4, pp 629-638
TL;DR: In this paper, the authors measured the diurnal and seasonal variations in carbon dioxide and methane fluxes between Sundarban biosphere and atmosphere using micrometeorological method during 1998-2000.
About: This article is published in Atmospheric Environment.The article was published on 2002-02-01. It has received 64 citations till now. The article focuses on the topics: Atmospheric methane & Carbon dioxide.
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors review 72 published articles to elucidate characteristics of biomass allocation and productivity of mangrove forests and also introduce recent progress on the study of MANGEO to solve the site and species-specific problems.

688 citations

Journal ArticleDOI
TL;DR: The impact of increasing N deposition on natural ecosystems is poorly understood, and further understanding is required regarding the use of drainage as a management tool, to reduce CH4 emissions from wetlands and to increase GHG sink from the restoration of degraded lands, including saline and sodic soils.
Abstract: Besides water vapour, greenhouse gases CO2, CH4, O3 and N2O contribute ~60%, 20%, 10% and 6% to global warming, respectively; minor contribution is made by chlorofluorocarbons and volatile organic compounds (VOC). We present CO2, CH4 and N2O fluxes from natural and relatively unmanaged soil–plant ecosystems (the ecosystems minimally disturbed by direct human or human-induced activities). All natural ecosystems are net sinks for CO2, although tundra and wetlands (including peatlands) are large sources of CH4, whereas significant N2O emissions occur mainly from tropical and temperate forests. Most natural ecosystems decrease net global warming potential (GWP) from –0.03 ± 0.35 t CO2-e ha–1 y–1 (tropical forests) to –0.90 ± 0.42 t CO2-e ha–1 y–1 (temperate forests) and –1.18 ± 0.44 t CO2-e ha–1 y–1 (boreal forests), mostly as CO2 sinks in phytobiomass, microbial biomass and soil C. But net GWP contributions from wetlands are very large, which is primarily due to CH4 emissions. Although the tropical forest system provides a large carbon sink, the negligible capacity of tropical forests to reduce GWP is entirely due to N2O emissions, possibly from rapid N mineralisation under favourable temperature and moisture conditions. It is estimated that the natural ecosystems reduce the net atmospheric greenhouse gas (GHG) emissions by 3.55 ± 0.44 Gt CO2-e y–1 or ~0.5 ppmv CO2-e y–1, hence, the significant role of natural and relatively unmanaged ecosystems in slowing global warming and climate change. However, the impact of increasing N deposition on natural ecosystems is poorly understood, and further understanding is required regarding the use of drainage as a management tool, to reduce CH4 emissions from wetlands and to increase GHG sink from the restoration of degraded lands, including saline and sodic soils. Data on GHG fluxes from natural and relatively unmanaged ecosystems are further compounded by large spatial and temporal heterogeneity, limited sensitivity of current instruments, few and poor global distribution of monitoring sites and limited capacity of models that could integrate GHG fluxes across ecosystems, atmosphere and oceans and include feedbacks from biophysical variables governing these fluxes.

287 citations

Journal ArticleDOI
TL;DR: The atmospheric fluxes of N(2)O, CH(4) and CO(2), from the soil in four mangrove swamps in Shenzhen and Hong Kong, South China were investigated in the summer of 2008 and were positively correlated with the soil organic carbon, total nitrogen, total phosphate, total iron and NH(4)(+)-N contents, as well as the soil porosity.

158 citations


Cites background from "Impact of Sundarban mangrove biosph..."

  • ...Some mangrove soil emitted a significant amount of greenhouse gases (e.g. Mukhopadhyay et al., 2002; Allen et al., 2007)....

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Journal ArticleDOI
TL;DR: In this article, the authors measured diurnal and seasonal variations of air-water CO2 exchange in relation to the occurrence of phytoplankton during January-December 2001.
Abstract: The Sundarban mangrove forest (4,264 km 2 ) constitutes about 3% of the total area of the world mangrove. We measured diurnal and seasonal variations of air‐water CO2 exchange in relation to the occurrence of phytoplankton during January‐December 2001. Diurnal variations of airflows showed that the minimum and maximum CO2 flux of 216.2 mmol m 22 h 21 and 49.9 mmol m 22 h 21 , respectively, occurred during the higher sea breeze. The average ratio of dissolved inorganic nitrogen (DIN 5 13.85 6 7.19 mmol L 21 ) to dissolved inorganic phosphorus (DIP 5 1.23 6 0.57 mmol L 21 ) was 11 6 4 and the surface water was undersaturated with respect to dissolved oxygen. The mean value of 0.1 6 0.08 for the ratio of phytoplankton production (P) to community respiration (R) indicated that the ecosystem was heterotrophic. The saturation of dissolved carbon dioxide with respect to the atmosphere varied seasonally between 59% and 156%, with minimum levels in postmonsoon and maximum levels in premonsoon/early monsoon (June/July). Out of the 36 genera of diatoms, 1 blue green alga, and 3 dinoflagellates that occurred throughout the year, only 6 reached bloom proportions in postmonsoon, when mangrove water was a sink of atmospheric CO2. Although 59.3% of the emitted CO2 was removed from the atmosphere by biological processes, on an annual basis, the Sundarban mangrove forest supplies 13.8 kg C ha 21 yr 21 of CO2 from water surface to the atmosphere. Even though it is important to compare all in and out fluxes, there is no direct link between CO 2 emission and the later CO2 removal by biological processes.

130 citations


Cites background from "Impact of Sundarban mangrove biosph..."

  • ...Sometimes it is not clear if an ecosystem is a net source or sink of CO2 (Mukhopadhyay et al. 2002b)....

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  • ...Anthropogenic processes, responsible for the conversion of a productive estuary to a heterotrophic one (Frankignoulle et al. 1998; Mukhopadhyay et al. 2002a), further complicate the uncertainty of the estimation of unaccounted sinks....

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  • ...Mukhopadhyay et al. (2002b) observed a positive correlation of fCO2(air) with Richardson number (Ri) and its values were found to be increasing in the atmosphere when there was an inversion condition in the Sundarban mangrove forest....

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Journal ArticleDOI
TL;DR: In this paper, seasonal and spatial variation of dissolved and atmospheric methane (CH 4 ) was measured in the estuaries of the Sundarban mangrove ecosystem from January to December 2003.

115 citations

References
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Journal ArticleDOI
TL;DR: In this article, the first micrometeorological-based measurements of CH4 emissions from Asian rice paddies of which we are aware were presented, using the tunable diode laser trace gas analyzer system (TGAS) developed at the University of Guelph.
Abstract: This paper presents the first micrometeorological-based measurements of methane (CH4) emissions from Asian rice paddies of which we are aware. The research features the tunable diode laser trace gas analyzer system (TGAS) recently developed at the University of Guelph. CH4 fluxes were measured between March 9 and 24, 1992, from an irrigated rice paddy field at the International Rice Research Institute (IRRI), the Philippines. The daytime CH4 flux averaged 6.0 μg m−2 s−1. The CH4 fluxes displayed a diurnal trend similar to daily soil temperature curves, with peak emissions of about 8 μg m−2 s−1 in the early afternoon. A tenfold increase in CH4 emissions (to about 70μg m−2 s−1) during a brief weeding experiment resulted from soil disturbance. Up to 25 μg m−2 s−1 of CH4 were released during a drying of the field, after which unsuitable soil redox potentials apparently suppressed methanogenesis. The CH4 flux was also arrested when the field was flooded with oxygen-rich water during a heavy rainstorm.

60 citations

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the sensitivity of the solutions of the model equations to variations in the entrainment formulation and in the initial and boundary conditions, and showed that the initial conditions for the mixed-layer height (h) and potential temperature (m) quickly lose their influence.
Abstract: Jump or slab models are frequently used to calculate the depth of the convectively mixed layer and its potential temperature during the course of a clear day. Much attention has been paid theoretically to the parameterization of the budget for turbulent kinetic energy that is required in these models. However, for practical applications the sensitivity of the solutions of the model equations to variations in the entrainment formulation and in the initial and boundary conditions is also very important. We analyzed this sensitivity on the basis of an analytical solution for the model which uses the well-known constant heat flux ratio. The initial conditions for the mixed-layer height (h) and potential temperature (θ m ) quickly lose their influence. Only the initial temperature deficit is important. The mixed-layer temperature at noon on convective days is insensitive to the entrainment coefficient c. It is governed by the integral of the heat input and by the stable lapse rate. A change in c from 0.2 to 0.5 leads to a variation of 20% in h. This is not very much considering the accuracy in the determination of h from actual observations.

53 citations

Journal ArticleDOI
TL;DR: An inventory of natural gas losses from the former Soviet Union's gas industry has been constructed from published Russian-language sources as discussed by the authors, which implies that substantial reductions in emissions could be achieved by investment to reduce losses.
Abstract: An inventory of natural gas losses from the former Soviet Union's gas industry has been constructed from published Russian-language sources. The results imply that in the late 1980s/early 1990s annual losses from Russia were in the range 35–59×109 cubic meters (24–40 Tg of CH4): estimates based on what are thought to be the more reliable sources place annual losses in the range 37–52×109 cubic meters (25–35 Tg of CH4). Of this amount, one half to two thirds of the emissions may have been from the extremely long and ageing gas pipeline system. Extrapolation of the estimates for Russian losses to the whole territory of the former Soviet Union suggests a probable total annual emission level from the whole ex-Soviet gas industry in the range 47–67×109 cubic meters of natural gas or 31–45 Tg of CH4 in these years. The envelope of minimum and maximum estimates for emissions from the former Soviet Union ranges from 29 to 50 Tg of methane. The limited availability of systematic and accurate published information on the emissions introduces significant uncertainty into the estimate. In an attempt to constrain emissions better, estimates of losses from specific causes were made using two or more independent approaches, where possible. A reasonable agreement between estimates was achieved in those cases. Our results imply that substantial reductions in emissions could be achieved by investment to reduce losses. Because of the high global warming potential and short lifetime of methane compared to carbon dioxide, reducing the large losses from the FSU may be among the most cost-effective short-term approaches available to reduce global anthropogenic greenhouse warming.

47 citations

Journal ArticleDOI
TL;DR: In this article, the authors summarized the more important conclusions to be drawn from the papers presented for discussion at the symposium on the Tilbury plume experiment and showed that α is a function of height of emission ( h c ).

28 citations