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

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.