波浪扰动对太湖底泥磷释放影响模拟

Experimental study on the effect of wave disturbances on the phosphorus dynamics in shallow lakes

  • 摘要: 为揭示波浪扰动对湖泊底泥磷释放的影响,在波浪水槽中模拟了不同波高情况下扰动对水体、水土界面、底泥间隙水的磷、溶解氧等的影响.结果显示,在大波扰动下,沉积物大量悬浮,水体总磷随之增加,溶解性磷增加却不显著;波浪扰动显著增加了水体和沉积物界面的溶解氧浓度,并增加了溶解氧在沉积物的侵蚀深度;波浪扰动降低了沉积物表层10 cm内间隙水中的磷浓度,而10 cm以下沉积物中间隙水中磷浓度基本保持不变.研究表明,波浪扰动可迅速增加水体中颗粒态的营养盐,但是对于溶解态营养盐,尤其是水体中活性磷浓度的影响,则受沉积物性质、水-沉积物间隙水磷浓度差,以及水-沉积物中氧含量等多方面因素的影响.

     

    Abstract: An experimental study was conducted in the water flume to investigate the effect of wave disturbances on the phosphorus releasing from the sediment in shallow lakes.The dissolved oxygen(DO)was measured every 5 seconds using an oxygen microelectrode sensor that is located at 1 cm above the sediment-water interface.Two wave amplitudes(2 cm and 10 cm) are used in the experiment.Results show that the strong wave disturbance can result in a rapid increase in suspended solids and total phosphorus concentrations.However,the influence on the soluble reactive phosphorus(SRP) concentration is insignificant.Wave disturbance can significantly increase the DO concentrations on the sediment-water interface and in the overlying water.For example,the observed DO concentration increases from 2.90 mg/L to 4.09 mg/L under the strong wave condition.Wave disturbance also increases DO penetration depth into the sediment.On the contrary,wave disturbance significantly reduces the SRP concentration in the interstitial water from the top 10 cm of sediment.The experiment reveals that the wave disturbance rapidly increases the particulate phosphorus concentration in the water,but has a minimal effect on the SRP concentration.The reason may be due to the complicating factors in controlling the SRP behaviors in shallow lakes.

     

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