| 云南程海富营养化过程的碳氧稳定同位素示踪 |
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| 引用本文： | 吴敬禄,王苏民.云南程海富营养化过程的碳氧稳定同位素示踪[J].第四纪研究,2003,23(5):557-564. |
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| 作者姓名： | 吴敬禄 王苏民 |
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| 作者单位： | 中国科学院南京地理与湖泊研究所,南京,210008 |
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| 基金项目： | 国家自然科学基金项目 (批准号 :40 2 73 0 0 4)，中国科学院知识创新工程重大项目 (批准号 :KZCX1 -SW -0 1 -1 5 )
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| 摘 要： | 近500年来程海生物成因碳酸盐δ18O和δ13C及其有机质δ13C同位素记录了程海湖泊环境由贫营养到中富营养的演化过程.碳酸盐δ18O记录显示,大约1690年程海成为封闭湖泊后,当时湖泊贫营养环境并没有发生变化,但造成了湖泊水体交换周期加长,碳酸盐δ13C、有机质δ13C及其色素含量、碳酸盐含量变化指示湖泊生产力开始增高.1911～1942年碳酸盐δ18O和δ13C及有机质δ13C突然显著偏负,表明湖泊生物种群结构发生转变,湖泊初级生产力迅速增加,湖泊由贫营养向中营养转化.湖泊沉积物色素含量及碳酸盐含量变化也记录了这一湖泊环境的转换过程.约1986年以来,随着藻类养殖业及其农业耕作方式的转变,程海水环境渐渐转变成目前的中富营养化状态.
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| 关 键 词： | 湖泊富营养 稳定同位素 初级生产力 程海 |
| 收稿时间： | 2003-05-23 |
| 修稿时间： | 2003年5月23日 |
STABLE ISOTOPIC TRACING OF HISTORICAL PROGRESSIVE EUTROPHICATION FROM LAKE CHENGHAI, YUNNAN IN CHINA |
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| Wu\ Jinglu\ \ Wang\ Sumin.STABLE ISOTOPIC TRACING OF HISTORICAL PROGRESSIVE EUTROPHICATION FROM LAKE CHENGHAI, YUNNAN IN CHINA[J].Quaternary Sciences,2003,23(5):557-564. |
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| Authors: | Wu\ Jinglu\ \ Wang\ Sumin |
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| Institution: | Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008 |
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| Abstract: | Stable isotopic ratios in lake sediment are effective trophic proxies, and eutrophication may result in decreasing of isotopic ratios. δ18O and δ13C in bicarbonate and δ13C in organic matter from a continuous sediment core from Lake Chenghai in southern China provide information on recent lake eutrophication. This closed lake, Lake Chenghai, located in the southwestern monsoon region has a varying eutrophic history, providing an ideal location to evaluate the role of changing biogeochemical conditions on stable isotopic fractionation in lacustrine carbonates and, in particular, to test the lake geochemical and isotopic response to eutrophication. The results showed that during the last 500 yr, Lake Chenghai has undergone major changes in productivity and eutrophication from oligotrophic lake to mesotrophic lake. In ca. 1690, the lake began to increase in productivity as Lake Chenghai became closed one from agriculture in the lake's watershed and the time of water exchange was longer, but the lake appears to have remained oligotrophic until ca. 1911. In the period between 1911～1942, the abrupt decrease δ13C org marks the transition from an oligotrophic to a mesotrophic lake ecosystem . Following this switch in the trophic state of Lake Chenghai, δ13C org becomes progressively lower, in parallel with isotope trends in the authigenic calcite and progressive eutrophication of the lake. After ca. 1942, Lake Chenghai evolved mesotrophic state, marked by an increase in organic carbon, CaCO3, pigments contents and obvious decreasing in stable isotopes ratios, which implies that an obvious change of lake ecosystem composition has occurred. In ca. 1986, the intensive human activities induced modern lacustrine productivity and eutrophic level. |
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| Keywords: | lake eutrophication stable isotope productivity Lake Chenghai |
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