Environmental changes inferred from lacustrine sediments and historical literature: A record from Gaoyou Lake, eastern China

Abstract

Gaoyou Lake is located in the lower reaches of the Huai River and west of the Jing-Hang Grand Canal in eastern China. Based on the temporal sequence of core sediments taken from Gaoyou Lake, multiple proxies of lacustrine sediments, such as particle size, magnetic susceptibility, TOC and C/N, were analyzed to reconstruct the environmental changes of Gaoyou Lake over the past 1100 years, along with verification from historical records. The study focused on the response of lake evolution to climate changes as well as to regional events and human activities. The results show that Gaoyou Lake experienced a stage of low water level during AD 900–1300 and then began to expand under the influence of frequent Yellow River floods after AD 1300. Subsequently, the water levels dropped because of the dry climate during AD 1600–1900. During the modern time after AD 1900, Gaoyou Lake was greatly influenced by warming climate as well as from anthropogenic forcing such as reclamation and deforestation in the catchment. Major regional events such as catastrophic floods and course changes of the Yellow River were interpreted to be related to abrupt changes of sediment characteristics. The human-induced factors, including levee construction and implementation of a river management strategy in order to guarantee the shipping on the Grand Canal, also have contributed greatly to the evolution process of Gaoyou Lake.