泸沽湖沉积物α纤维素的提取及其稳定碳同位素研究初探

湖泊沉积是环境气候变化的敏感指示器 ,在沉积过程中有机大分子α纤维素不易发生降解 ,其碳链上的C、H、O原子也不会与外界发生交换 ,故沉积物α纤维素的碳同位素能真实地反映原始环境信息。湖泊沉积物中的α纤维素含量少 ,笔者经过反复条件试验 ,得出了从湖泊沉积物提取α纤维素的简便可行的方法。泸沽湖是云贵高原上一半封闭湖泊 ,湖区人为活动干扰较微弱 ,该湖对环境变化敏感。笔者提取了泸沽湖沉积物柱的α纤维素 ,并研究了其碳同位素 ,结果表明 ,α纤维素碳同位素灵敏、精确地反映了该湖一百年来的环境信息 :泸沽湖沉积物有机质以内生为主 ;气候变化趋势为冷—暖—冷—暖。

EXTRACTION OF α-CELLULOSE FROM LUGU LAKE SEDIMENT AND ITS STABLE CARBON ISOTOPE

Lacustrine sediment is a sensitive indicator of environmental and climatic changes. During the sedimentation processes, α\|cellulose is not easy to degrade, and its C, H and N of carbon\|chains do not exchange with the matter of environment. The carbon isotopic composition of sediment α\|cellulose truly, accurately records the information on the past. The α\|cellulose concentration of lake sediment is very low. After many experiments, an available method is established to extract α\|cellulose from lake sediment. Lugu Lake is a semi\|closed fault lake on the Yunnan\|Guizhou Plateau. There is little anthropogenic interference, so its lacustrine sediment sensitively recorded the change of natural environment. By extracting α\|cellulose from a sediment core in Lugu Lake, and studying carbon isotope, we found that the carbon isotope of sediment α\|cellublose can indicate sensitively and accurately the environmental information about Lugu Lake since 1889: sediment organic cellulose is mainly from lake itself; the climatic trend is: colder→warmer→colder→warmer.