玄武湖沉积物磷形态的垂向变化和生物有效性

采用不同的化学提取法,分析玄武湖西北湖区沉积物中各形态磷、生物可利用磷(BAP)的垂向变化,探讨了各层沉积物中磷的生物有效性。结果表明,沉积物中总磷以无机磷为主,BAP占总磷的20%~52.6%,玄武湖底泥的磷有较好的生物可利用性。不同地点沉积物各磷形态和BAP的垂向变化有较大的差异。1号采样点的总磷、无机磷、铁磷和BAP质量比在沉积0~20 cm处较高,20~40 cm逐渐减小,说明0~20 cm内释磷潜力较大;2号采样点的总磷和无机磷质量比先减小,20~40 cm逐渐增加,而BAP和铁磷质量比随深度增加呈上升趋势,说明2点深层具有较大的释磷潜力。铁磷与BAP相关性较好,这部分磷具有较大的潜在释放风险。

Vertical distribution and bio-availability of various forms of phosphorus in the sediments of Xuanwu Lake

The vertical distribution of various forms of phosphorus and bio-available phosphorus （BAP） in the sediments of the northwest part of Xuanwu Lake were analyzed with different chemical extractions. In addition, the bio-availability of the phosphorus in different layers was discussed. The results show that inorganic phosphorus is the major form of the total phosphorus in the sediments, and BAP accounts for 20% - 52.6% of the total phosphorus, which showed high bioavailability. The phosphorus forms and BAP vary with horizontal and vertical positions. The total phosphorus, inorganic phosphorus, BAP, and iron-phesphoms （Fe-P） contents were high at a depth of 0-20cm at the first sampling point, and then decreased at 20-40 cm of depth. This shows that the potential release capacity of P at 0-20 cm of depth is higher. The concentrations of total phosphorus and inorganic phosphorus decreased at 0-20 cm of depth and increased at 20-40 cm of depth at the second sampling point, but BAP and Fe-P increased along with the depth consistently. This shows that the deeper layer at the second sampling point had a higher potential release capacity of phosphorus. Fe-P had a good correlation with BAP. Both had a high potential risk of release.