摘要
为了研究水位变化对CO_2排放的影响规律,评价自然水位的变化对湿地生态功能的影响,选择黄河中游典型蒲草湿地进行人工注水处理,对自然样地(To)、一次注水至地表(T)、持续注水至地表(Tf)、持续注水至-30 cm水位(Th)等4种处理进行持续7日监测。研究发现,各注水处理的CO_2排放速率与To有显著差异,但各处理之间差异不显著,CO_2排放速率平均值表现为To>Th>Tf>T;自然样地CO_2排放有昼高夜低的特征,但存在日际差异;T处理24 h后有持续12 h的快速上升过程,37.69 h后于低值处波动,与To相比,前5天排放速率波动特征略有滞后,后期基本一致;监测过程中Tf和Th变化特征基本一致,Tf排放速率略小,但都与To明显不同,除了监测前24 h,二者在7日监测过程中波动较To平缓;7日CO_2排放总量为To>Th>Tf>T(5.19、4.19、3.62、3.39 mol?m-2),Th、Tf、T处理排放速率分别下降19.3%、30.2%、34.6%。研究证明,短期水位波动对CO_2排放的影响最明显,中国西北部河流水位的频繁波动能大幅度影响湿地碳库功能。
To study the pattern of how water level affects the emission of CO2 and to evaluate the effects of natural water level changes on ecological functions of wetlands,the authors performed water-injected monitoring experiment in typical cattail(Typha angustifolia Presl)wetlands in middle reaches of Yellow River,and monitored the emission of CO2 from four treatments of wetlands,namely,To(natural plot),T(injecting water to soil surface at one time),Tf(injecting water continuously to the earth surface),and Th(injecting water continuously to the water level of^-30 cm)for 7 days.The study found that the CO2 emission rate of each water-injected treatment was significantly different from that of To,but the difference between the other three treatments was not significant,average CO2 emission rate showed To>Th>Tf>T.Emission of CO2 from natural sample plots was high in the daytime while decreased at night,but also varied from one day to another;After 24 hours,T had a rapid increased CO2 emission for 12 hours,and a low value fluctuation after 37.69 hours,compared with To,the fluctuation characteristics of the emissions rate in the first 5 days were slightly delayed,and the latter period was basically accordant.Tf and Th basically shared the same characteristics of changes,and the emission rate of Th was slightly smaller than that of Tf,however,significantly different from To,Tf and Th were subject to smaller fluctuations in the seven-day monitoring period except the first 24 hours.During monitoring,the total CO2 emission showed To>Th>Tf>T(5.19,4.19,3.62,and 3.39 mol·m^-2 respectively),and Th,Tf,and T caused reductions of 19.3%,30.2%,and 34.6%separately.This study proves that a short-term water level fluctuation could cause significant impacts on the emission of CO2,and frequent fluctuations of river levels in northwestern China could affect the carbon pool function of wetlands dramatically.
作者
吕海波
张虹
LV Haibo;ZHANG Hong(Weinan Normal University/Key Laboratory for Eco-Environment of Multi-river Wetlands in Shaanxi Province,Weinan 714099,China)
出处
《生态环境学报》
CSCD
北大核心
2018年第10期1943-1948,共6页
Ecology and Environmental Sciences
基金
渭南师范学院自然科学基金项目(15ZRRC12)
陕西省教育厅专项科研计划项目(16JS033)
陕西省水利厅专项计划(2015slkj-26)
关键词
CO2瞬时排放速率
蒲草湿地
水位变化
人工注水试验
instantaneous emission rates of CO2
cattail wetlands
changes of water level
manual water injection test
作者简介
吕海波(1980年生),男,副教授,博士,主要从事气候变化研究。E-mail:lhboboo@163.com。
