Abstract: Through the analysis of total organic carbon, total nitrogen, and total phosphorus concentrations in surface sediment cores from Wuli Bay of Taihu Lake, the historical record of phosphate input in the Bay was studied, and in combining with the analysis of carbon isotope value of bulk sedimentary organic matter, the evolution process of the primary productivity and eutrophication in the Bay was revealed. The carbon isotope value of the sediment total organic C was -26.6‰ on average, with a variation between -27.0‰ and -26.3‰. It was decreased with depth up to the lowest value at 5 cm, subsequently increased gradually up to the highest value at 12 cm, and then fluctuated downward with the depth, which suggested that the evolvement of eutrophication, productivity, and primary producer was associated with the increasing phosphorus input from human activities. Moreover, the concentrations of total phosphorus and the C/N atomic ratios of total organic carbon to total nitrogen recorded the succession process of aquatic plant community from float grass to float grass + algae to algae.

Key words: Photoinhibition, Thermal dissipation, P_max, Photosynthetic pigment, Eupatorium adenophorum