Spatial and temporal patterns of methane dynamics in the tropical mangrove dominated estuary, NE coast of Bay of Bengal, India
Spatial and temporal patterns of methane dynamics in the tropical mangrove dominated estuary, NE coast of Bay of Bengal, India
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DOI：
10.1016/j.jmarsys.2006.11.001
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发表时间：
2007-11-01
影响因子：
2.8
通讯作者：
Jana, T. K.
中科院分区：
文献类型：
--
作者：
Biswas, H.;Mukhopadhyay, S. K.;Jana, T. K.
2003年1月至12月，测量了Sundarban红树林生态系统河口溶解甲烷和大气甲烷(CH4)的季节和空间变化。这个独特的红树林生态系统(9630公里(2))是胡格利-马提亚河口系统(孟加拉湾东北海岸)的一部分，约占世界红树林总面积的3%。以红树林为主的河口水体中溶解甲烷浓度在11.0~129.0 nmol.L-1之间，排放速率在1.97~134.6 mmolm(-2)d(-1)之间。甲烷排放在季风后浮游植物达到水华比例时达到最大值。在雨季后，红树林输送的物质在水体透明度增加和河流输入营养盐较低的情况下可以促进浮游植物水华的发生。而河口的溶解甲烷浓度在10.3~59.25nmoL L-1之间，排放速率在0.88~148.6 mmolm~(-2)d~(-1)之间。胡格利口盐度梯度带的甲烷浓度并没有随着盐度的增加而呈下降趋势，这是由于甲烷从位于河口下部的红树林横向运移而来的。红树林原始林地孔隙水中溶解甲烷的最大浓度为5769nmoL L-1，明显低于滨海盐沼、潮汐淡水湿地。这表明产甲烷菌被硫酸盐和硝酸盐还原细菌强烈氧化或竞争。邻近森林生态系统的甲烷排放量(18.36 mmolm-2d-1)高于红树林水体的甲烷排放量。考虑到水生和森林生态系统的甲烷排放速率，得到孙德尔班红树林环境的面积平均排放速率为47.28×10(-5)molKm(-2)yr(-1)。在红树林覆盖的全球面积上外推平均土壤甲烷排放量，而不考虑其从水中的排放，可能会产生不准确的估计。(C)2006爱思唯尔B.V.保留所有权利。
Seasonal and spatial variation of dissolved and atmospheric methane (CH4) was measured in the estuaries of the Sundarban mangrove ecosystem from January to December 2003. This unique mangrove forest ecosystem (9630 km(2)), a part of the Hooghly-Matia estuarine system (NE coast of Bay of Bengal) comprises about 3% of the total area of the world's mangroves. Dissolved methane concentrations in the mangrove dominated estuarine water (Muriganga, Saptamukhi and Thakuran) were observed between 11.0 and 129.0 nmol L-1 with emission rates between 1.97 and 134.6 mu mol m(-2) d(-1). Methane emission showed maximum rate during post-monsoon when phytoplankton reached blooming proportion. During post-rnonsoon materials transported from the mangrove forest could stimulate phytoplankton bloom when transparency of water column was increased and river input of nutrient was low. However, dissolved methane concentrations in the Hooghly estuary, the main river water flushing channel showed lower values between 10.3 and 59.25 nmol L-1 with emission rates between 0.88 and 148.6 mu mol m(-2) d(-1). Methane concentrations in the salinity gradient zone of the Hooghly estuary did not show any decreasing trend with increased salinity due to its lateral transport from the mangrove forest situated at the lower stretch of the estuary. Dissolved methane concentration in the pore water collected from the virgin mangrove forest showed a maximum concentration of 5769 nmol L-1 which was considerably lower compared to that of coastal salt marsh, tidal fresh water wetland. This indicated intense oxidation or out competition of methanogenic bacteria by sulfate and nitrate reducing bacteria. Methane emission from the adjacent forest ecosystem (18.36 mmol m(-2) d(-1)) was higher compared to that in the mangrove water. Considering methane emission rates from the aquatic and forest ecosystems, an area average rate of 47.28 x 10(5) mol km(-2) yr(-1) for Sundarban mangrove environment was obtained. Extrapolating over the global area covered by mangrove forest with area average soil methane emission rate without considering its emission from water could yield inaccurate estimation. (c) 2006 Elsevier B.V All rights reserved.