摘要： 通过对太湖 TJ-2钻孔的¹³⁷Cs、粒度、总有机碳(TOC) 、总氮(TN)、总磷(TP)及化学元素等多指标综合分析,探讨了太湖大浦湖区近百年来的环境演变特征。研究结果表明,20世纪 50 年代以前,沉积物中大部分金属元素如 Al、Mn、Cu、Cr、Ni、Zn与粘土含量具很好的相关性,相关系数在0.74~ 0.82 之间。此阶段湖泊生产力不高,水环境较好,沉积物以较低的营养元素含量为特征。50-90年代,是太湖向现代湖泊环境转化的显著时期,湖区生产力大幅提高,人为活动对湖泊系统严重干扰,湖区迅速达到富营养化。在沉积物中表现为 Fe/Mn 值下降,有机碳、总氮、总磷与重金属元素急剧上升,且重金属元素变化明显不同于沉积物粒度及 Al元素变化曲线。90年代以后,湖区一直持续着富营养化状态,富营养趋势渐缓,沉积物中粘土含量上升、营养元素稍降及重金属指标变化不明显的趋势很好地体现了这一特征。TJ-2钻孔显示的环境信息与湖泊实际环境监测结果基本一致。

关键词: 太湖, 大浦湖区, 沉积物, 湖泊富营养化

Abstract: The environmental evolution characteristics of Dapu area in Taihu Lake in the last 100 years are discussed through multi-proxy analysis of ¹³⁷Cs, grain size, TOC, TN, TP and geochemical elements from the core TJ-2. The results indicate that most metal elements such as Al, Mn, Cu, Cr, Ni, Zn in the sediments deposited prior to 1950s have good correlativities with the content of clay (the correlations are between 0.74 and 0.82). In that stage, the productivity was not high, the water environment was relatively good, and the sediments was characterized by a relatively lower content of nutrient elements. From 1950s to 1990s, the Dapu area got into the period of modern environmental lake, whose productivity remarkably increased, human activities seriously disturbed the lake system and the lake area reached eutrophication rapidly, which is shown by a drop of Fe/ Mn value and a sharp increase of the values of TOC, TN, TP and heavy metal elements. The changes of heavy metal elements are different from the curves of grain size and Al element. After 1990s, the content of clay increased, the nutrient elements decreased a little and various indexes of heavy metals did not change obviously. These characteristics show that the lake area kept the eutrophication character with a tendency of eutrophication being slowed down. Environmental information reflected by the core T-2 coincides with the practical environmental monitoring results.

Key words: Taihu Lake, Dapu area, sediments, lake eutrophication

中图分类号: 

• X131.2