南极苔原沼泽温室气体通量变化特征及其对气候变化的响应  

VARIATION OF SUMMERTIME GREENHOUSE GAS FLUXES FROM TUNDRA MARSHES AND THEIR RESPONSE TO CLIMATE CHANGE IN MARITIME ANTARCTICA

作　　者：王培 叶文娟[1] 朱仁斌[1] 徐华[2] Wang Pei;Ye Wenjuan;Zhu Renbin;Xu Hua(Polar Institute of Polar Environment,University of Science and Technology of China,Hefei 230026,China;State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Science,Nanjing 210091,China)

机构地区：[1]中国科学技术大学地球和空间科学学院极地环境与全球变化安徽省重点实验室,安徽合肥230026 [2]中国科学院南京土壤研究所土壤与农业可持续发展国家重点实验室,江苏南京210091

出　　处：《极地研究》2020年第1期13-24,共12页Chinese Journal of Polar Research

基　　金：国家自然科学基金(41576181,41776190);中国科学院战略性先导科技专项(XDB40000000)资助。

摘　　要：以南极阿德雷岛苔原沼泽为研究区域,2016年12月至2017年1月南极夏季期间观测研究了温室气体CH4、CO2和N2O通量的变化规律及其对环境因子的响应关系。结果表明:光照条件下干旱苔原沼泽表现为CH4吸收,通量为(–5.4±4.3)μg CH4·m^–2·h^–1,半干旱苔原与淹水苔原沼泽表现为净排放;三个类型苔原沼泽观测点均表现为N2O净吸收,最高吸收通量出现在淹水苔原,为(–2.6±2.4)μg N2O·m^–2·h^–1;黑暗条件下苔原沼泽一致表现为CH4和N2O净排放。光照与土壤水分减少增加了苔原CH4有氧氧化吸收,同时促进了反硝化作用对N2O的还原转化。观测期间所有观测点均表现为CO2的汇,最高CO2净交换量与光合作用强度都出现在淹水苔原区,分别为(–40.1±17.6)μg CO2·m^–2·h^–1和(91.2±26.5)mg CO2·m^–2·h^–1;而最高苔原沼泽呼吸速率出现在干旱苔原观测点,为(73.1±17.6)μg CO2·m^–2·h^–1。夏季适宜的温度、降水条件促进了苔原植被的光合作用,增加了苔原沼泽CO2吸收量。CO2、N2O、CH4通量随时间变化的相互关系规律不显著(P>0.05),但在降水与温度波动下,N2O与CH4通量都随CO2通量呈现相似的波动。三种温室气体与各种环境因子之间的响应关系值得进一步研究;不同光照条件对CH4、N2O排放量的估算有重要影响。During the austral summer of 2016-2017,CH4,CO2,and N2O fluxes and selected environmental variables were measured over tundra marshes on Ardley Island in maritime Antarctica.In the presence of sunlight,a net CH4 flux of-5.4±4.3μg·m^–2·h^–1 was measured at the dry tundra site,while net CH4 emissions were detected at the mesic and waterlogged sites.Under sunlight conditions,maximum N2O flux was-2.6±2.4μg·m^–2·h^–1,and was measured at the waterlogged site;all sites showed net N2O consumption.In the total absence of sunlight,all sites showed net CH4 and N2O emissions.Light and water enhance CH4 consumption via aerobic oxidation and promote denitrification and the subsequent formation of N2O.Under sunlight conditions,all three sites acted as CO2 sinks.The highest net CO2 flux and photosynthetic flux occurred at the waterlogged site(-40.1±17.6 mg·m^–2·h^–1 and-91.2±26.5 mg·m^–2·h^–1),while the highest ecosystem respiration rate occurred at the dry tundra site(73.1±17.6μg·m^–2·h^–1).Favorable temperature and precipitation conditions during the Antarctic summer promote photosynthesis in tundra vegetation,resulting in increased CO2 uptake by marshes.Relationship between time and fluxes of the three greenhouse gases is not statistically significant(P>0.05).However,under the conditions of variable precipitation and temperature,fluctuations in N2O and CH4 fluxes are similar to those in CO2.Results indicate that different light conditions,even those under the same sunlight intensity,have considerable influence on estimates of CH4 and N2O fluxes.Relationships between the three greenhouse gases and between the gases and various environmental factors deserve further study.

关 键 词：南极 苔原沼泽 CO2通量 N2O通量 CH4通量 

分 类 号：P467[天文地球—大气科学及气象学] X16[环境科学与工程—环境科学]