• 关键词：沉积物  磷形态  空间分布  影响因素  释放贡献

• 基金项目：

• 张奇
• 西南林业大学国家高原湿地研究中心, 昆明 650224

• 喻庆国
• 西南林业大学国家高原湿地研究中心, 昆明 650224

• 王胜龙
• 西南林业大学国家高原湿地研究中心, 昆明 650224

• 朱云轩
• 西南林业大学国家高原湿地研究中心, 昆明 650224

• 李丽萍
• 西南林业大学国家高原湿地研究中心, 昆明 650224

• 危锋
• 西南林业大学环境科学与工程学院, 昆明 650224

• 王行
• 西南林业大学国家高原湿地研究中心, 昆明 650224

• 朱金鑫
• 西南林业大学林学院, 昆明 650224

• 摘要：采用连续分级提取法提取了剑湖沉积物中弱吸附态磷（NH₄Cl-P）、可还原态磷（BD-P）、铁铝氧化态磷（NaOH-rP）、有机质结合态磷（NaOH-nrP）、钙结合态磷（HCl-P）和残渣态磷（Res-P）6种形态的磷，并对表层（0~10 cm）沉积物磷形态水平空间分布、沉积柱芯（0~75 cm）磷形态垂向空间分布和释放贡献特征进行了分析.结果表明：表层沉积物6种磷形态平均含量差别较大，其含量由高到低排序为HCl-P > Res-P > NaOH-rP > NaOH-nrP > BD-P > NH₄Cl-P；HCl-P含量是NH₄Cl-P的72倍，3种稳定磷形态（HCl-P、Res-P和NaOH-rP）含量是3种潜在可移动磷形态（NaOH-nrP、BD-P和NH₄Cl-P）含量的6.5倍.NH₄Cl-P、BD-P、NaOH-nrP和NaOH-rP含量的变异系数明显高于HCl-P和Res-P含量的变异系数.尽管表层沉积物6种磷形态的水平空间分布特征不尽相同，4条主要入湖河流入湖口区6种磷形态含量平均值之和是湖周浅水区的1.40倍，但能指示出入湖河流是外源磷污染物输入的主要通道.虽然沉积柱芯6种磷形态垂向空间分布特征各异，6种磷形态入湖口区表层平均含量分别是底层的1.60、1.87、1.87、1.61、1.18和1.15倍，其他湖区表层平均含量分别是底层的1.18、1.34、1.39、1.41、0.97和0.83倍，但除HCl-P和Res-P在其他湖区为随深度增加而缓慢递增外，基本上能反映出6种磷形态含量在入湖口区随深度增加而递减的程度都远强于其他湖区.外源磷输入和人为活动影响是3种潜在可移动磷形态和NaOH-rP的主要因素，流域地质背景是HCl-P和Res-P的主要影响因素.6种磷形态在入湖口区快释放贡献率多为负值，表示以滞留状态为主，慢释放贡献率全为正值，表示都为释放状态，滞留贡献最大和释放贡献最大的都是NaOH-rP；其他湖区快释放贡献率和慢释放贡献率多为正值，表示都以释放状态为主，NaOH-rP释放贡献最大，Res-P滞留贡献最大.

• Abstract：Six phosphorus (P) fractions, including NH₄Cl-P, BD-P, NaOH-rP, NaOH-nrP, HCl-P and Res-P in sediments of Jianhu Lake were obtained by sequential extraction method. The horizontal distribution of P fractions in surface sediments (0~10 cm), and both of the vertical distribution and release contributions of P in sediment cores (0~75 cm) in Jianhu Lake were analyzed. The results show that:①The average P contents in surface sediments differed greatly for six fractions, which were in a decreasing order as HCl-P > Res-P > NaOH-rP > NaOH-nrP > BD-P > NH₄Cl-P. The content of HCl-P was 72 times as much as that of NH₄Cl-P, and the content of three stable P fractions (HCl-P, Res-P, and NaOH-rP) was 6.5 times as much as that of three potentially mobile P fractions (NaOH-nrP, BD-P, and NH₄Cl-P). The coefficient of variations for NH₄Cl-P, BD-P, NaOH-nrP and NaOH-rP were obviously higher than that for HCl-P and Res-P. ②The horizontal distribution characteristics of six P fractions in surface sediments were not consistent. The sum of the average content of six P fractions in the estuary areas of four main rivers into the lake was 1.4 times as much as that in shallow water area of the lake, but the distribution revealed that the into-lake rivers were the main sources for exogenous P pollutants. ③The vertical distribution characteristics of six P fractions in sediment cores were also not consistent. In the estuary areas, the average content of six P fractions in surface sediments were 1.60, 1.87, 1.87, 1.61, 1.18 and 1.15 times as much as that in the bottom, respectively. In other areas of the lake, the average content of six P fractions in surface sediments were 1.18, 1.34, 1.39, 1.41, 0.97 and 0.83 times as much as that in the bottom respectively. Except for HCl-P and Res-P in other areas, all P fractions show higher contents in surface sediments than in bottom. When comparing estuary and other areas, the P fractions in the estuary areas had greater diminishing rate than in other areas. ④Exogenous P inputs and human activities were major factors explaining dynamic changes of the three potentially mobile P fractions and NaOH-rP, while the geological background in watershed were major factors explaining the dynamic changes of HCl-P and Res-P. ⑤In estuary areas, P fractions with a rapid release contribution rate were mainly negative value, indicating that most in a retention status, while the slow release contribution rate were all positive, indicating fully in a released status. Among them, NaOH-rP had the highest contribution for both release and retention. In other areas, rapid release contribution rate and slow release contribution rate were mostly being positive, all P fractions were mainly in a releasable status, regardless of the release contribution rate. NaOH-rP had the highest contribution for release, and Res-P had the highest contribution for retention.

• Key words：sediment  phosphorus fraction  spatial distribution  influence factors  release contribution

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