中文摘要：

利用IVANOFF法,研究了洱海表层沉积物有机磷形态及其空间分布特征,探讨了有机质对各形态有机磷含量分布的影响.结果表明：洱海北部和南部的浅水湖区沉积物w（OM）较高（2.50%～11.72%）,而中部的深水湖区沉积物w（TP）较高（710.29～1 961.22 mgkg）;沉积物w（OP）为212.71～526.23 mgkg,与w（TP）分布趋势一致;沉积物不同形态有机磷的含量为Residual-Po（残渣态有机磷）〉Fulvic-P（富里酸结合态有机磷）〉HCl-Po（酸提取态有机磷）〉NaHCO3-Po（活性有机磷）〉Humic-P（腐殖酸结合态有机磷）.沉积物w（OM）与w（OP）w（TP）,w（Fulvic-P）和w（Humic-P）之间均呈显著正相关（P〈0.01）,与w（Residual-Po）呈显著负相关（P〈0.01）,与w（NaHCO3-Po）和w（HCl-Po）之间相关性不显著（P〉0.05）.洱海沉积物有机磷主要以非活性有机磷（Residual-Po和Humic-P）为主（平均占58.74%）,且w（Fulvic-P）占w（OP）的百分比均高于营养水平较高的湖泊,而w（HCl-Po）占w（OP）的百分比相对较低（除E7采样点外）.即洱海沉积物有机磷形态特征决定了其生物有效性较低.沉积物有机磷赋存形态特征很可能是上覆水磷浓度相对较低的重要原因,而沉积物w（TOC）w（OP）〈200则意味着其有机磷的潜在释放风险较大.

英文摘要：

Organic phosphorus fractions and their spatial distribution characteristics in surface sediments of Lake Erhai were investigated by the IVANOFF method,and the impacts of organic matter（OM） on the contents of different organic phosphorus fractions were discussed.The results indicated that the higher OM contents of the sediments,ranging from 2.50% to 11.72%,were distributed in the shallow lake districts in the northern and southern areas of Lake Erhai.However,the higher TP contents,ranging from 710.29 to 1961.22 mg/kg,were mainly distributed in the deep water lake district in the central part of the lake.The average concentration of OP in the sediments from Lake Erhai was 212.71 to 526.23 mg/kg,and its distribution trend was consistent with that of TP.The contents of organic phosphorus with different extraction fractions ranked as follows： Residual-Po Fulvic-P HCl-Po NaHCO3-Po Humic-P.The content of OM was positively associated with the ratio of the content of OP to the content of TP,the content of Fulvic-P and the content of Humic-P（P0.01）,and negatively associated with the content of Residual-Po（P0.01） in the sediments.However,the content of OM had no obvious relation with the content of NaHCO3-Po or the content of HCl-Po（P0.05） in the sediments.The main form of OP in the sediments of Lake Erhai was non-labile organic phosphorus（Residual-Po and Humic-P）,accounting for 58.74% on average.The percentage of the content of Fulvic-P to the content of OP was higher than that of higher nutrition level lakes,and the percentage of the content of HCl-Po to the content of OP was lower（except for the E7 point）.The characteristics of organic phosphorus forms in the sediments of Lake Erhai resulted in lower bioavailability.Accordingly,the distribution characteristics of organic phosphorus forms in the sediments may be the main reason that lower concentrations of phosphorus existed in the overlying water in Lake Erhai.However,the ratio of the content of TOC to the content of OP in the sediments,which wa