Key factors affecting spatial variation of methane emissions from freshwater marshes
Key factors affecting spatial variation of methane emissions from freshwater marshes
复制标题
DOI：
10.1016/s0045-6535(02)00804-4
复制
发表时间：
2003-04-01
期刊：
影响因子：
8.8
通讯作者：
Li, XP
中科院分区：
文献类型：
--
作者：
Ding, WX;Cai, ZC;Li, XP
为了解同一地区不同类型植物生长的沼泽和同一类型植物生长的沼泽样地CH4排放的空间变化机制，我们对富营养化淡水沼泽分为三种类型的区域进行了CH4排放测量：2001年8月对三江平原毛蕊草（Carex lasiocarpa）、毛蕊草（Carex meyeruana）和德叶霞（Deyeuxia angustifolia）的植物类型、孔隙水中CH4浓度、地上植物生物量和原位茎密度进行了研究。同一区域不同湿地和同一湿地内不同样地的CH4排放空间差异均较大。3个湿地的CH4排放通量率为17.2 ~ 66.5 mg CH4 m(-2) h(-1)，变异系数为34.76%，而柽柳草、毛蕊草和德叶夏湿地的CH4排放通量率分别为21.6 ~ 66.5（39.61%）、17.2 ~ 45.0（29.26%）和19.1 ~ 33.0 mg CH4 m(-2) h(-1)（17.51%）。随着静水深度的显著增加，CH4排放通量速率和空间变异均显著增加。静水深度通过改变植物凋落物在静水中的淹没量，在很大程度上控制了区域内不同沼泽CH4排放的空间变化，为产甲烷菌提供了稳定的有机碳，控制了孔隙水中CH4的浓度。此外，地上植物生物量通过控制沼泽向大气排放CH4的途径（茎密度），决定了沼泽样地CH4排放的空间变化。2003爱思唯尔科学有限公司版权所有。
To understand the mechanism for spatial variation of CH4 emissions from marshes grown with different type of plants in a region and plots within a certain marsh grown with one type of plants, we measured CH4 emissions from a region in which eutrophic freshwater marshes were divided into three types: Carex lasiocarpa, Carex meyeruana and Deyeuxia angustifolia according to plant type as well as CH4 concentration in porewater, aboveground plant biomass and stem density in situ in Sanjiang Plain of Northeast China in August 2001. Spatial variation of CH4 emissions from both different marshes in a region and different plots within a certain marsh was high. The flux rates of CH4 emissions from three marshes ranged from 17.2 to 66.5 mg CH4 m(-2) h(-1) with 34.76% of variation coefficient, whereas the values in Carex lasiocarpa, Carex meyeriana and Deyeuxia angustifolia marshes varied from 21.6 to 66.5 (39.61%), from 17.2 to 45.0 (29.26%) and from 19.1 to 33.0 mg CH4 m(-2) h(-1) (17.51%), respectively. Both the flux rates and spatial variation of CH4 emissions strongly increased as standing water depth increased significantly. Standing water depth greatly governed the spatial variation of CH4 emissions from different marshes in a region by changing the amount of plant litters inundated in standing water, which provided labile organic C for methanogens and controlled CH4 concentrations in porewater. Moreover, the aboveground plant biomass determined spatial variation of CH4 emissions from plots within a certain marsh by controlling the pathways (stem density) of CH4 emissions from the marsh into the atmosphere. (C) 2003 Elsevier Science Ltd. All rights reserved.