不同扰动方式对底泥/水系统中生物有效磷的影响

Influence of different disturbance on bio-available phosphorus in sediment/ water system

为了解底泥扰动对水体磷迁移转化的影响,通过模拟试验研究了底泥不同扰动方式(间歇扰动、持续扰动)下上覆水中生物有效磷(BAP)及其组成的变化规律。结果表明,间歇扰动作用下,在24～216h和216～624 h之间,BAP分别稳定在0.09 mg·L^(-1)和0.052 mg·L^(-1),显著低于初始状态(0.679 mg·L^(-1));持续扰动作用下,BAP在第6 h达到最大值(2.437 mg·L^(-1)),随后下降,24 h后稳定在0.759 mg·L^(-1),但其组成以颗粒态生物有效磷(BAPP)为主(超过93%)。间歇扰动作用下,溶解性总磷(TDP)占BAP的百分比下降了约10%,而无扰动试验中,该值有所增加。说明扰动促进了TDP向BAPP的转化,降低了水体富营养化的直接风险。

The present paper is aimed to define the rule of phosphorus （P） migration and transformation under sediment disturbance conditions. The variation of bioavailable P （BAP） and its components were investigated under the conditions of different disturbance （continuous or intermittent disturbance） in laboratory experiments. The waters and sediments used were taken from a campus canal. The results show that the concentrations of BAP stabled at 0.09 mg·L^-1 （24-216 h） and 0.052 mg·L^-1 （216-624 h） under the conditions of intermittent disturbance and they were obviously lower than the initial state （0.679 mg·L^-1）. On the other hand, the highest value of BAP was reached after 6 h of continuous disturbance and then BAP decreased slightly. The content of BAP remained at about 0.759 mg·L^-1 from 24 h to the end of the experiment, and it was slightly higher than the initial state （0.679 mg·L^-1）. Based on the content of BAP under the different conditions, the highest content of BAP was under continuous disturbance, followed with no disturbance and intermittent disturbance. Under the conditions of continuous disturbance, bioavailable particulate P （BAPP） was the dominant fraction, more than 93% of BAP. On the other hand, total dissolved P （TDP） was the main fraction in BAP under the conditions of intermittent disturbance. Moreover, the proportions of TDP in BAP decreased by about 10%, compared to the initial state, but the ratio slightly increased in the no disturbance experiment. It is evident indicating that disturbance promotes the transformation of phosphorus from TDP to BAPP and reduces the direct risk of eutrophication. In addition, soluble reactive P （SRP） was not the main fraction in TDP under intermittent and continuous disturbance conditions, compared with the no disturbance experiment. It is suggested that sediment disturbance plays a significant role in adsorbing P and converting it to more stable forms.