近1500年来新疆艾比湖同位素记录的气候环境演化特征

利用介形虫壳体^δ18O,^δ13C及其沉积物有机质^δ13C同位素组成等环境代用指标,重建了西北干旱区艾比湖地区近1500年来气候环境演化特征。结果表明,气候不稳定性不但出现在时段约660～760A.D.及约1380～1500A.D.由暖干变冷湿的气候转换时期,也出现在时段约1050～1150A.D.及约1850～1940A.D.由冷湿变暖干的转换时期。尤其是由冷湿到暖干的气候转换时期,频繁而大幅度的气候变化影响湖泊水环境的稳定连续性,限制了介形虫等湖泊生物的生存,造成湖泊生态环境系统的破坏。而在百年尺度上艾比湖地区气候表现为暖干、冷湿的组合特征。约1850年开始,气候出现明显的干旱化趋势。

CLIMATIC CHANGE RECORD FROM STABLE ISOTOPES IN LAKE AIBI, XINJIANG DURING THE PAST 1500 YEARS

The climatic and environmental history in the last 1 500 years was reconstructed by analyzing environmental proxies, such as ^δ18 O and ^{δ 13} C in ostracoda shell, ^{δ 13} C of organic matter, etc. From the Aibi lake sediments—— a closed basin in the arid region of northwestern China. The results show that the instability of climate occurred in the transition periods, i.e the periods of 660～760A.D. and 1380～1500A.D. when the climate was changed from warm dry condition to cold wet condition and the periods of 1050～1150A.D. and 1850～1940A.D. when cold and wet climate was becoming warm and dry. The dramatic climate change, especially in the transitional period from cold and wet climate to warm and dry climate, limited the continuity of aquatic environment and restricted the survival of ostracode, and broke down the lake ecosystem. On a century time scale, the climatic pattern in the Aibi lake region is expressed as the combination of warm dry and cold wet. A warm dry climatic trend is clearly displayed from ca.1850A.D.