贵州红枫湖沉积物磷赋存形态的空间变化特征

摘要

选取贵州省红枫湖这一典型的亚深水型人工湖泊作为对象,研究了6个代表性湖区沉积物柱芯磷的赋存形态,结合水体温度和溶解氧现场监测结果,探讨了该类型湖泊沉积物内源磷释放风险.研究结果表明,红枫湖沉积物总磷含量普遍较高,表层沉积物总磷含量均值大于1500 mg/kg,明显高于下部沉积物.NaOH-SRP和rest-P是沉积物磷的主要赋存形态.NH4Cl-P和BD-P含量表层最高,随深度增加明显降低,rest-P含量在垂向上变化不大.人为活动是造成沉积物总磷及赋存形态空间分布差异的主要原因,工业废水和网箱养鱼活动等大大增加了沉积物NaOH-SRP含量.红枫湖深水湖区底部水温多在14.5 ～23.5℃之间,随季节变化底部水温差异明显,溶解氧含量通常不高于1.5 mg/L,整体处于季节性缺氧或厌氧状态.以NaOH-SRP为主的沉积物磷赋存形态和深水缺氧环境大大增加了红枫湖沉积物内源磷释放的风险,在未来的研究中亟待加强对该类型湖泊沉积物内源磷释放机制、控制因素及治理措施的研究.%Lake Hongfeng is a man-made deep lake. Phosphorus of sediment samples that were collected from representative six water areas were analyzed. Water temperature and dissolved oxygen were investigated four times in the field by multi-parameter water quality observation analyzer YSI. The results showed that total phosphorus in sediment was generally high. The average value of total phosphorus in surface sediment was more than 1500 mg/kg, significantly higher than that in the bottom sediments. NaOH-SRP and rest-P were the main forms of phosphorus in sediment. NH4C1-P, BD-P and HC1-P contents decreased with depth, and rest-P contents were stabile in vertical. Human activities (e. g. chemical waste water and artificial fish) greatly increased NaOH-SRP contents in sediment. Temperature of bottom water was between 14. 5 ?23. 5X1 , and the maximum temperature differences was 9. 9X^. in different seasons. The bottom water was seasonal anoxic or anaerobic, which may result in changes of sediment phosphorus forms. Risk of endogenous phosphorus release increased due to anoxic condition of sediment-water interface in deep lake.