三岔湖沉积物揭示的湖泊营养化进程与人类活动的关系

在210Pb和137Cs定年基础上,研究了三岔湖沉积物理化性质的垂直和水平变化格局,揭示了三岔湖沉积物的特性、沉积速率、碳氮磷变化格局与人类活动和湖泊富营养化进程的关系.三岔湖不同时期沉积物的TOC、TN、TP与三岔湖水质呈现同样的变化格局.建库初期三岔湖水质为贫营养状态,随着人类活动的加剧,水质不断恶化.沉积物的沉积速率和碳氮磷含量的变化与人类活动密切相关,工、农、渔业、旅游业等人类活动导致三岔湖湖泊营养化进程加快.控制人类活动的强度是改善湖泊水质的关键.网箱养殖是三岔湖沉积物中磷的最重要来源,停养后沉积物中磷含量的下降将是一个相当漫长的过程.

Relationship among sediment characteristics,eutrophication process and human activities in the Sancha Lake,Sichuan, Southwestern China

Based on the 210Pb and 137Cs dating, the article analyzes the vertical and lateral changes in their physical and chemical features that have happened to the lake sediment in Sancha Lake in Sichuan Province, Southwestern China. It shows the changes of Sancha Lake sediment contents and deposition rates are closely related to human activities and lake eutrophication progress. The changes of total nitrogen (TN), total phosphorus (TP) and total organic carbon (TOC) concentrations in the lake sediment strongly coincide with that of Sancha Lake water quality. When the reservoir was first built, the lake water was in an oligotrophic state. As human activities increased, the water quality started to deteriorate and continued to do so. Human activities such as manufacturing, farming, fishing, and tourism have accelerated the eutrophication of Sancha Lake. The key to improve the water quality lies in limiting human activities. The most important source of phosphorus in sediment is from cage culture. It takes a very long time for the phosphorus concentration in the sediment to actually go down after such practices cease.