Effect of sediment resuspension on underwater light field in shallow lakes in the middle and lower.pdf

114 Science in China: Series D Earth Sciences 2006 Vol.49 Supp. I 114—125 DOI: 10.1007/s11430-006-8111-y Effect of sediment resuspension on underwater light field in shallow lakes in the middle and lower reaches of the Yangtze River: A case study in Longgan Lake and Taihu Lake 1, 2 1 1 1 1 ZHANG Yunlin , QIN Boqiang , ZHU Guangwei , GAO Guang , LUO Liancong CHEN Weimin1 1. Nanjing Institute of Geography Limnology, Chinese Academy of Sciences, Nanjing 210008, China; 2. Graduate School of Chinese Academy of Sciences, Beijing 100039, China Correspondence should be addressed to Qin Boqiang (email: qinbq@) Received September 16, 2005; accepted January 10, 2006 Abstract Based on three continuous in situ underwater light field measurement under different wind waves conditions in Longgan Lake, Meiliang Bay of Taihu Lake in July 2003 and littoral zone near TLLER in July 2004, respectively, the effects of sediment resuspension caused by wind waves on PAR diffuse attenuation, absorption coefficients and euphotic depths are analyzed. In Longgan Lake, PAR diffuse attenuation coefficients during small, middle and large wind waves were 1.74, 2.02 − 1 and 2.45 m , respectively, and the corresponding PAR spectral diffuse attenuations ranged from 0.98 − 1 to 2.97, 1.34 to 3.95 and 1.80 to 5.40 m , respectively. In Meiliang Bay, PAR diffuse attenuation co- − 1 efficients were 2.63, 3.72, 4.37 m during small, middle and large wind waves. PAR diffuse attenua- tion coefficients increased by 41% and 66% from small to middle, large wind waves, respective