Abstract:

The spectral absorption coefficients of particulate matter in Lake Donghu,Lake Liangzihu and Lake Honghu were studied based on the data collected on 27 September and 1~3 October 2007.The absorption spectra of total particulates were similar to those of phytoplankton，suggesting that phytoplankton accounted for a large contribution of particulate matter.Significant higher absorption coefficients were recorded in Lake Donghu and Lake Liangzihu than in Lake Honghu，indicating that the underwater climate was better in Lake Honghu than in Lake Donghu and Lake Liangzihu.Larger spatial differences of particulate matter absorption coefficients were found in Lake Liangzihu and in Lake Honghu than in Lake Donghu.The absorption spectra of nonalgal particles of the three lakes showed the same pattern,following an exponential increase toward short wavelengths with an average slope of 1231±032 μm-1,1196±084 μm-1,1198±168 μm-1 over the 400~700 nm interval in Lake Donghu,Liangzihu and Honghu,respectively.Significant positive relationships were found between phytoplankton absorption coefficients 〖WTBX〗a〖WTBZ〗ph(440),〖WTBX〗a〖WTBZ〗ph(675) and phytoplankton pigment concentration (〖WTBX〗p〖WTBZ〗<0005),suggesting that phytoplankton absorption coefficients could be calculated from phytoplankton pigment concentration.There were significant correlations between total particulate matter,nonalgal particulate absorption coefficients and the concentrations of total suspended solids,organic suspended solids,inorganic suspended solids.A significant linear relationship was found between phytoplankton absorption coefficients and organic suspended solids concentration,suggesting phytoplankton dominated in organic suspended solids