『Abstract
　The adsorption of PO4^3- on lake sediments has an important influence on the transport, degradation, and ultimate fate of P in lake ecosystems. Organic matter in sediment strongly affects PO4^3- adsorption, with light fraction organic matter (LFOM), the labile fractions representing only a small proportion of the total organic matter, playing a key role in nutrient cycling in lakes. however, little is known about the effect of LFOM on PO4^3- adsorption by sediments. This study examined the effects of LFOM removal on PO4^3- adsorption by lake sediments with different trophic status. Results showed that the removal of LFOM did not significantly affect PO4^3- adsorption kinetics, which was greatest during the first 0.5 h and reached an equilibrium state thereafter. The amount of PO4^3- adsorbed decreased due to LFOM removal from the sediments, especially in the first 0.5 h. The PO4^3- adsorption rates for the sediments from Gonghu Lake, Wuli Lake and Yuehu lake decreased from 302.44 mg (kg h)^-1 to 138.93 mg (kg h)^-1, 322.88 mg (kg h)^-1 to 149.21 mg (kg h)^-1 and 415.36 mg (kg h)^-1 to 46.77 mg (kg h)^-1, respectively. The removal of LFOM accelerated PO4^3- release from sediments to the overlying water, and PO4^3- adsorption efficiency decreased by 83.75％, 70.90％ and 66.75％ for Gonghu Lake, Wuli Lake and Yuehu Lake, respectively. Two plausible explanations contributed to the decrease, one was the replacement of PO4^3- which was in the form of Fe/Al-bound P in the sediment by OH- due to the increased pH, and the other is the destruction of LFOM colloids by the carboxyl group (-COOH) and hydroxyl (-OH). 』

1. Introduction
2. Materials and methods
　2.1. Sampling and analyses
　2.2. Removal of organic matter from sediment samples
　2.3. Adsorption isotherm
　2.4. Adsorption kinetic measurements
　2.5. Infrared spectroscopy
3. Results and discussion
　3.1. Sediment characteristics
　3.2. Effect of LEOM removal on PO4^3- adsorption kinetics
　3.3. Effect of LFOM removal on PO4^3- adsorption isotherms
　3.4. Infrared spectroscopy theory
4. Conclusions
Acknowledgements
References