本文選題：青藏高原　切入點：高寒濕地　出處：《甘肅農業(yè)大學》2015年碩士論文　論文類型：學位論文

【摘要】：在全球氣候變化的背景下,溫度變化和降水變化已引起青藏高原高寒濕地水位變化。青藏高原高寒草地生態(tài)系統對氣候變化極其敏感,而高寒濕地生態(tài)系統是高寒草地生態(tài)系統的重要組成部分,研究高寒濕地溫室氣體釋放與水位變化的關系,有利于深入了解草原生態(tài)系統受氣候變化的影響及其對氣候變化的響應,以及合理推測未來趨勢,為推進國家氣候變化應對行動,制定草原生態(tài)恢復的適應性管理政策提供科學依據。為了探討水位變化對高寒濕地生態(tài)系統溫室氣體釋放的影響,采用“中型實驗生態(tài)系”的技術手段模擬全球變化中的水位降低,對青藏高原東部的若爾蓋高原?紅原縣的高寒濕地生態(tài)系統進行研究。試驗設置兩個處理:自然水位WN(約土壤表面0.00 cm)和降低水位WD(自然下降至約土壤表面以下40.00cm),測定不同水位下高寒濕地生態(tài)系統CO2、CH4和N2O的釋放量,并據此計算全球增溫潛能(GWP),得出了以下結論:(1)水位變化對高寒濕地CO2、CH4和N2O三種溫室氣體釋放有不同的影響:水位變化對高寒濕地CO2釋放沒有顯著影響,WD處理和WN處理CO2累積釋放量分別為23.52g·m-2和20.97g·m-2,沒有顯著差異,CO2釋放速率與水位沒有顯著相關性;水位變化對高寒濕地CH4釋放有顯著影響,WD處理和WN處理CH4累積釋放量分別為1.79g·m-2和0.86g·m-2,WD處理較WN處理減少了52.18%,CH4釋放速率與水位呈極顯著相關性,水位降低到一定程度,濕地會從CH4的釋放源轉變?yōu)镃H4的吸收匯;水位變化是影響N2O釋放的關鍵因素,WD處理和WN處理N2O累積釋放量分別為6.72mg·m-2和-7.36mg·m-2,N2O釋放速率與水位呈顯著相關性,一定范圍內的水位下降N2O釋放將增加,高寒濕地水位進一步下降,N2O釋放速率將減小。(2)高寒濕地生態(tài)系統CO2釋放量與土壤溶解性有機碳(DOC)含量呈顯著正相關關系,N2O釋放量與土壤NO3--N含量呈顯著正相關關系。(3)高寒濕地生態(tài)系統CO2釋放量與溫度有密切的關系,且降低水位提高了土壤呼吸對溫度的敏感度;高寒濕地CH4釋放受土壤溫度影響顯著,且降低水位提高了CH4釋放量與溫度的擬合度;高寒濕地生態(tài)系統N2O通量較小,且影響因素較多,溫度對N2O通量的影響效果被其他影響因素掩蓋,沒有發(fā)現溫度與高寒濕地生態(tài)系統N2O釋放量之間存在明顯的相關性。(4)同一時間尺度上,WD處理的GWP顯著低于WN處理,說明高寒濕地水位降低有利于減弱溫室氣體的全球增溫潛能。
[Abstract]:Under the background of global climate change, the changes of temperature and precipitation have caused the changes of water level of alpine wetlands on the Qinghai-Xizang Plateau, and the alpine grassland ecosystem of the Tibetan Plateau is extremely sensitive to climate change. The alpine wetland ecosystem is an important part of alpine grassland ecosystem. The relationship between greenhouse gas release and water level change in alpine wetland is studied. Contributing to an in-depth understanding of the effects of climate change on grassland ecosystems and their response to climate change, as well as reasonable projections of future trends, in order to advance national climate change responses, In order to study the effect of water level change on greenhouse gas release from alpine wetland ecosystem, The "medium Experimental ecosystem" is used to simulate the global change in the water level, the eastern part of the Qinghai-Xizang Plateau in the Zoige Plateau? Study on alpine wetland ecosystem in Hongyuan county. Two treatments were set up: natural water level WN (about 0. 00cm soil surface) and low water level WD (natural drop below about 40. 00cm) to determine alpine wetland ecology under different water levels. The emission of CO _ 2H _ 4 and N _ 2O from the system, Based on this, the global warming potential (GWPN) is calculated, and the following conclusions are drawn: the variation of water level has different effects on the release of three greenhouse gases, CO _ 2N _ 2 Ch _ 4 and N _ 2O in alpine wetland: the change of water level has no significant effect on CO2 release from alpine wetland and WN. The cumulative release of CO2 was 23.52 g 路m ~ (-2) and 20.97 g 路m ~ (-2), respectively. There was no significant difference between CO _ 2 release rate and water level. The water level change had significant influence on the CH4 release from alpine wetland. The cumulative release of CH4 in WD treatment and WN treatment were 1.79 g 路m -2 and 0.86 g 路m -2, respectively. Compared with WN treatment, the release rate of CH4 decreased by 52.18g 路m ~ (-2), and the water level decreased to a certain extent. The water level change is the key factor affecting the N2O release. The cumulative N2O emission of WD and WN treatments are 6.72 mg 路m ~ (-2) and -7.36 mg 路m ~ (-2) N _ 2O, respectively. There is a significant correlation between the water level and the water level. Within a certain range of water levels falling, N2O emissions will increase, The release rate of N2O in alpine wetland will be decreased further. 2) there is a significant positive correlation between the amount of CO2 released from alpine wetland ecosystem and the content of dissolved organic carbon (DOC) in soil. There is a significant positive correlation between the release of N2O and the content of NO3--N in soil. (3) the amount of CO2 released from alpine wetland ecosystem is closely related to temperature. Lowering water level increased the sensitivity of soil respiration to temperature, CH4 release from alpine wetland was significantly affected by soil temperature, and decreased water level increased the fit between CH4 emission and temperature, and N2O flux in alpine wetland ecosystem was small. The effect of temperature on N2O flux was masked by other factors. There was no obvious correlation between temperature and N2O emission from alpine wetland ecosystem. 4) the GWP of WWD treatment was significantly lower than that of WN treatment on the same time scale, which indicated that the decrease of water level in alpine wetland was beneficial to reduce the global warming potential of greenhouse gas.
【學位授予單位】：甘肅農業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X171

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本文編號：1641910