香港米埔红树林湿地土壤温室气体排放的时空变化特征  

Spatial and temporal variations of soil greenhouse gas emissions in the Mai Po mangrove wetland of Hong Kong

作　　者：许加星 罗明汉 程俊翔[2,3] Xu Jiaxing;Luo Minghan;Cheng Junxiang(School of Environmental Engineering,Nanjing Institute of Technology,Nanjing 211167,Jiangsu,P.R.China;State Key Laboratory of Lake and Watershed Science for Water Security,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 211135,Jiangsu,P.R.China;Jiangxi Research Academy of Ecological Civilization,Nanchang 330036,Jiangxi,P.R.China)

机构地区：[1]南京工程学院环境工程学院,江苏南京211167 [2]中国科学院南京地理与湖泊研究所,湖泊与流域水安全全国重点实验室,江苏南京211135 [3]江西省生态文明研究院,江西南昌330036

出　　处：《湿地科学》2025年第1期108-121,共14页Wetland Science

基　　金：国家重点研发计划项目(2024YFE0106400);中国科学院南京地理与湖泊研究所科技计划项目(NIGLAS2022TJ13和NIGLAS2022GS09)资助。

摘　　要：红树林湿地被视为热带和亚热带地区最富含碳的湿地之一,但由于受到潮水频繁淹没以及周围地区大量营养物质输入的影响,红树林湿地成为甲烷(CH_(4))、一氧化二氮(N_(2)O)等温室气体的潜在排放源。为了揭示红树林湿地土壤温室气体排放的时空变异性及其环境影响因子,在香港米埔红树林湿地开展了为期1 a的月尺度野外监测。结果表明,近陆带、中间带和近海带的红树林湿地土壤平均CO_(2)通量差异不显著,而CH_(4)通量在中间带明显较高,主要由于厌氧环境促进了CH_(4)生成,土壤N_(2)O通量平均值则在近陆带显著较高,可能因为近陆带土壤中较高的有机物含量刺激了硝酸盐供应及反硝化作用。红树林湿地土壤温室气体排放在不同季节差异显著,冬季CH_(4)排放显著较低,这是由于低温和高盐度抑制了CH_(4)产生;夏季土壤CO_(2)排放通量显著高于其他季节,而冬季显著低于其他季节,主要与土壤温度和有机物含量的变化对微生物活动的影响有关。此外,土壤温室气体排放通量还存在显著的年内变异性,月平均CH_(4)和N_(2)O通量的相对标准偏差均超过115%,红树林湿地土壤温室气体排放具有较高的时空变异性。研究结果可为准确评估红树林在未来气候变化中的作用提供参考。While mangroves are regarded as one of the most carbon-rich forests in the tropical and subtropical regions,their soils could at the same time be potential net sources of greenhouse gases(GHGs)such as methane(CH_(4))and nitrous oxide(N_(2)O)owing to frequent flooding by tidal water and considerable nutrient inputs from upland areas.In this study,we characterized the spatial and temporal variabilities,as well as the environmental and biotic controls,of soil GHGs emissions from a subtropical mangrove in Hong Kong through intensive field measurements at monthly intervals over one full year.The average soil CO_(2)flux was not significantly different among the three tidal positions of the mangrove(from far to near along the direction perpendicular to the coastline),while that of CH_(4)was significantly higher in the middle zone owing to a more anaerobic environment for methanogenesis.A significantly higher mean soil N_(2)O flux was observed in the landward zone,probably because of the greater organic matter content in soils that stimulated nitrate supply and denitrification.Significant seasonal variations in soil GHGs emissions were also detected in this mangrove,with significantly lower CH_(4)flux in winter in response to the low temperature and high salinity that suppressed CH_(4)production,as well as significantly higher and lower CO_(2)emissions in the summer and winter,respectively,owing to differences in soil temperature and organic matter content that governed microbial activities.Significantly higher mean N_(2)O flux was found in the middle zone in autumn than the other three seasons,which could be related to the greater supply of soil available nitrogen for N_(2)O production.Furthermore,we noted significant intra-annual variability of soil GHGs fluxes,with the relative standard deviations of both monthly CH_(4)and N_(2)O fluxes being over 115%.Our findings highlight the need of taking into consideration the high spatial and temporal variability of soil GHGs fluxes in order to have an accurate assessment of th

关 键 词：二氧化碳 甲烷 氧化亚氮 红树林 香港米埔 

分 类 号：X51[环境科学与工程—环境工程]