• 关键词：草海湿地  沉积物  磷形态  释放风险  影响因素

• 基金项目：国家自然科学基金（No.U1612441）；贵州省科技计划项目（No.黔科合支撑［2020］4Y020号，［2020］1Y168号）；贵州省生物研究所科技计划项目（No.黔生所字［2021］08号）

• 蒋娟
• 贵州科学院， 贵州省生物研究所，贵阳 550009

• 龙云川
• 贵州科学院， 贵州省生物研究所，贵阳 550009;贵州大学， 资源与环境工程学院，贵阳 550025

• 姚小琴
• 贵州大学， 资源与环境工程学院，贵阳 550025

• 胡菁
• 贵州大学， 资源与环境工程学院，贵阳 550025

• 徐婉莹
• 贵州大学， 资源与环境工程学院，贵阳 550025

• 周少奇
• 贵州大学， 资源与环境工程学院，贵阳 550025

• 摘要：以草海湖区表层沉积物为研究对象，采用Hupfer改进后的化学连续提取法分析20个采样点沉积物中磷形态特征，通过不同磷吸附释放风险指数评估草海的潜在生态风险，并探讨影响磷形态和吸附释放的因素.结果表明，草海湖区表层沉积物总磷（TP）含量为780.95~1229.42 mg·kg^-1，存在轻度污染；磷形态含量分布表现为NaOH-NRP＞Res-P＞HCl-P＞BD-P＞NaOH-SRP＞NH₄Cl-P，TP与HCl-P、BD-P和NaOH-NRP均呈显著正相关（p＜0.001）.草海沉积物生物有效磷（BAP）含量为486.71~812.86 mg·kg^-1，占TP的59.18%~69.38%，内源磷负荷相对较大.沉积物磷吸附释放相关指数的变化范围分别为：磷吸附平衡浓度（EPC₀）：0.001~0.839 mg·L^-1（明显高于上覆水SRP）；磷吸附指数（PSI）：35.47~159.40 （mg·L）·（100 g·μmol）^-1；磷吸附饱和度（DPS）：3.64%~16.51%；磷释放风险指数（ERI）：3.03%~39.57%.草海沉积物磷释放风险存在显著的空间异质性，以较低释放风险为主，县城-西海码头区域为高释放风险区域.主成分分析（PCA）和冗余分析（RDA）显示：草海湖区表层沉积物各形态磷受理化性质、酶活性影响，其中Zn、Cd、Pb、中性磷酸酶（NP）、碱性磷酸酶（AKP）、总氮（TN）影响比重较大；Fe_ox、Al_ox，NH₄Cl-P、BD-P和过氧化氢酶（CAT）与草海沉积物磷的吸附释放指数均显著相关.总体来看，草海自身的生态环境和周边的人类活动是显著影响沉积物中磷形态及磷吸附释放的主要因素.

• Abstract：20 sediment samples were collected from the Caohai wetland to analyze the fraction distribution and release risk of phosphorus. Phosphorus fractions were analyzed by the chemical sequential extraction modified by Hupfer， the potential ecological risk was assessed by different phosphorus adsorption-release risk indexes， and finally， the factors affecting phosphorus fractions and adsorption-release of phosphorus were explored. The results showed that total phosphorus （TP） content in the surface sediments of Caohai wetland was slightly polluted in a range of 780.95~1229.42 mg·kg^-1. The distribution of phosphorus fraction content was in the following order： NaOH-NRP＞Res-P＞HCl-P＞BD-P＞NaOH-SRP＞NH₄Cl-P. TP was positively correlated with HCl-P， BD-P and NaOH-NRP （p<0.001）. The content of bioavailable phosphorus （BAP） in Caohai sediments ranged from 486.71 to 812.86 mg·kg^-1， accounting for 59.18%~69.38% of TP， suggesting that the endogenous phosphorus loading was relatively high. The equilibrium phosphorus concentration （EPC₀） was in the range of 0.001~0.839 mg·L^-1 （significantly higher than SRP content in overlying water）， the phosphorus sorption index （PSI） varied from 31.33 to 159.40 （mg·L）·（100 g·μmol）^-1， the degree of phosphorus saturation （DPS） was 3.64%~20.15%， and the phosphorus release risk index （ERI） changed from 3.03% to 39.57%. There was significant spatial difference in phosphorus release risk of sediments in Caohai， where low release risk was dominated， while the area closing to Weining county and Xihai Dock was in high degree of release risk. Results of Principal component analysis （PCA） and redundancy analysis （RDA） showed that the physicochemical properties and enzyme activities had significant impact on all phosphorus fractions in the surface sediments of Caohai wetland， among which Zn， Cd， Pb， neutral phosphatase （NP）， alkaline phosphatase （AKP） and total nitrogen （TN） accounted for a large proportion of variance contribution. Fe_ox， Al_ox， NH₄Cl-P， BD-P and catalase （CAT） were significantly correlated with the phosphorus adsorption and release indexes of sediments in Caohai. In general， the ecological environment of Caohai and the human activities were the main factors that significantly affected the phosphorus fractions and phosphorus adsorption-release in the sediments.

• Key words：Caohai wetland  sediment  phosphorus fractions  release risk  influencing factors

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