Phosphorus (P) is a key indicator of the aquatic organism growth and eutrophication in lakes. The distribution and speciation of P and its release characteristics from sediments were investigated by analyzing sediment and water samples collected during high flow and low flow periods. Results showed that the average concentrations (ranges) of total phosphorus (TP) in the surface and deep water were 0.06 mg L-1 (0.03–0.13 mg L-1) and 0.15 mg L-1 (0.06–0.33 mg L-1), respectively, while the average concentration (range) of TP in sediments was 709.17 mg kg-1 (544.76–932.11 mg kg-1). The concentrations of TP and different forms of P varied spatially in the surface sediments, displaying a decreasing trend from south to north. P also varied topographically from estuarine areas to lake areas. The vertical distribution of TP and different forms of P were observed to decrease as depth increased. The P concentrations during the low flow period were higher than those during the high flow period. Inorganic phosphorus (IP) was the dominant form of P, accounting for 61%–82% of TP. The concentration of bioavailable phosphorus in sediments was relatively large, indicating a high risk of release to overlying water. The simulation experiment of P release from sediments showed that the release was relatively fast in the first 0-5 min and then decreased to a plateau after 1 hr. Approximately 84–89% of the maximum amount of P was released during the first hour.
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机译：磷（P）是湖泊中水生生物生长和富营养化的关键指标。通过分析高流量和低流量期间沉积物和水样，研究了磷在沉积物中的分布，形态及其释放特征。结果表明，表层和深水中的总磷（TP）的平均浓度（范围）为0.06 mg L -1 （0.03-0.13 mg L -1 ）和0.15 mg L -1 （0.06-0.33 mg L -1 ），而沉积物中TP的平均浓度（范围）为709.17 mg kg -1 （544.76–932.11 mg kg -1 ）。地表沉积物中总磷和不同形态磷的含量在空间上变化，从南到北呈递减趋势。从河口地区到湖泊地区，P的地形也各不相同。 TP的垂直分布和不同形式的P随着深度的增加而减小。低流量期间的P浓度高于高流量期间的P浓度。无机磷（IP）是磷的主要形式，占总磷的61％–82％。沉积物中可生物利用的磷的浓度相对较高，表明释放到上覆水中的风险很高。磷从沉积物中释放的模拟实验表明，在最初的0-5分钟内释放速度相对较快，然后在1小时后降至平稳状态。在第一个小时内释放出最大量P的约84–89％。
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