【摘要】：高寒草甸是青藏高原重要的草地類型之一。目前增溫對高寒草甸溫室氣體通量影響的研究較少,尤其在不同尺度的增溫條件下,溫室氣體通量的響應(yīng)尚不明確。因此,設(shè)置多梯度增溫實驗,模擬未來不同幅度增幅情況,對預(yù)測高寒草甸溫室氣體通量的變化具有重要意義。為深入地認(rèn)識氣候變暖對高寒草甸溫室氣體通量的影響,假設(shè)高寒草甸溫室氣體通量的周轉(zhuǎn)速率在增溫條件下隨增溫梯度而加快。在青藏高原納木錯地區(qū)高寒草甸,采用開頂箱法(Open-top chambers,OTCs)設(shè)置對照(T0,不增溫)以及4個不同程度的增溫處理(T1、T2、T3、T4,分別增溫1、2、3、4℃),結(jié)合靜態(tài)箱-氣相色譜法對增溫處理后的CO_2、CH_4和N_2O通量進行同步觀測。對3個生長季(2013—2015年)進行連續(xù)觀測發(fā)現(xiàn):(1)地下5 cm土壤3年的平均溫度相對于對照處理分別增加1.73℃(T1)、1.83℃(T2)、3.03℃(T3)和3.53℃(T4);(2)高寒草甸生長季平均呼吸(CO_2)為(42.6±9.11)mg·m~(-2)·h~(-1),同時具有較強的CH_4吸收能力,達(dá)到(-47.96±8.76)μg·m~(-2)·h~(-1),其N_2O通量維持在較低水平,為(0.3±0.46)μg·m~(-2)·h~(-1);(3)在高寒草甸生長季,溫室氣體通量與溫度以及水分均具有顯著的相關(guān)關(guān)系,但增溫未能顯著改變生長季溫室氣體平均通量。以上結(jié)果表明,增溫所引起的其他環(huán)境因素的改變(如伴隨不同梯度增溫下土壤水分變化的不確定性),導(dǎo)致高寒草甸在短期內(nèi)進行內(nèi)部調(diào)節(jié),并維持溫室氣體通量穩(wěn)定。
[Abstract]:Alpine meadow is one of the important grassland types in Qinghai-Tibet Plateau. At present, the effect of warming on greenhouse gas flux in alpine meadow is less studied, especially in different scales, the response of greenhouse gas flux is not clear. Therefore, it is of great significance to predict the change of greenhouse gas flux in alpine meadow by setting up multi-gradient warming experiment and simulating the future increase of different amplitude. In order to understand the effect of climate warming on greenhouse gas flux in alpine meadow, it is assumed that the turnover rate of greenhouse gas flux in alpine meadow is accelerated with the increase of temperature gradient. In the alpine meadow of Namuco area, Qinghai-Xizang Plateau, the open top box method (Open-top chambers,OTCs) was used to set up the control (T0, no temperature increase) and four different degrees of warming treatment (T1OT2T2T3T4, respectively). The flux of CO_2,CH_4 and N2O after heating treatment was observed synchronously by static box gas chromatography. Continuous observation of three growing seasons (2013-2015) showed that: (1) the average temperature of 3 years of underground 5 cm soil increased by 1.73 鈩，

本文編號：2407759