东平湖沉积物中磷的赋存形态及其空间分布特征

用采集沉积物样本分析测试的方法，探究了东平湖沉积物中磷的赋存形态特征及其空间分布特征。结果表明，东平湖表层沉积物总磷（TP）含量在500 ~ 812 mg kg?1之间，平均值为 618 mg kg?1，空间分布上表现为湖区中部和西南部含量高、东南部含量低的趋势。沉积物中磷以非活性磷（Ca-P、Res-P）为主，非活性磷与总磷（TP）呈显著正相关（P < 0.01）；在总磷中钙结合态磷（Ca-P）占比最高（62.6%），残渣态磷（Res-P）次之（36.2%），活性磷（Ex-P、Al-P、Fe-P）占比最低（1.20%）。靠近湖区边缘的点位沉积物中活性磷占总磷的比例略高于湖区中部点位；表层（0 ~ 4 cm）沉积物中各形态磷含量变化幅度大于下层，随垂直深度增加活性磷含量和非活性磷含量分别表现为下降和上升的变化趋势，这可能与人类活动影响以及沉积物中磷的来源和转化机制不同有关。

Phosphorus Fractions and their Spatial Distribution Characteristics in the Sediments of Dongping Lake

In order to explore the fractions and spatial distribution characteristics of phosphorus (P) in the sediments of Dongping Lake, 30 surface and 6 core sediment samples were collected from Dongping Lake in October, 2018 and then the contents of total P (TP) and P fractions in the sequential extraction of exchangeable P (Ex-P), aluminum-bound P (Al-P), iron-bound P (Fe-P), calcium-bound P (Ca-P) and residual P (Res-P) were analyzed. The results showed that the TP content in the surface sediments of Dongping Lake ranged from 500 to 812 mg kg?1, with an average of 618 mg kg?1, a light pollution level. The TP content was the highest in the middle and southwest of the lake area, but was relatively lower in the southeast. Inactive P was the main P fraction in the sediments, which was dominated by Ca-P (accounting for 62.6% of TP) and then followed by the Res-P (accounting for 36.2% of TP). TP and inactive P had an extremely significant positive correlation (P < 0.01). The active P, which was the sum of Ex-P, Al-P and Fe-P, was the least (accounting for 1.20% of TP) in the sediment of Dongping Lake. Due to the influence of human activities, the proportions of active P in TP of sediments near the lakeshore area were slightly higher than those in the middle of the lake area. The content of P fractions had a greater variation in the surface layer (0-4 cm) compared with the deep layers. In general, the active P content was decreased with the increase of the depth, while the change of inactive P was contrary to that of active P, which might be related to the difference in the source and transformation mechanism of P fractions.