反复扰动下加藻对不同形态磷相互转化的影响

以太湖梅梁湾沉积物和上覆水为材料,研究了反复扰动下加藻与否对沉积物中不同形态磷数量分布的影响.试验结束时,对照试验、单纯反复扰动、加藻反复扰动其上覆水中溶解性总磷(DTP)含量依次增加了75%、62.5%和18.8%,单纯反复扰动和加藻反复扰动试验上覆水中溶解性无机磷(DIP)浓度分别增加了300%和100%.加藻反复扰动和单纯反复扰动下,沉积物中钙磷(Ca-P)的净减少量分别为31mg/kg DW和 9mg/kg DW.表明, DTP和DIP的释放主要取决于沉积物中铁铝结合态磷(Fe/Al-P)和Ca-P的减少量.沉积物中Fe/Al-P和 Ca-P的含量有所降低,主要归因于反复扰动和藻类的同化吸收作用.然而,加藻反复扰动和单纯反复扰动下,藻类可利用磷(AAP)却有所增加.这表明藻类浓度较低时,其对磷的吸附同化量明显低于沉积物中Fe、黏土颗粒以及CaCO3的吸附量.尽管AAP的形成与还原速率很难测定,但其却可以很好地表征沉积物中内源磷的生物有效性.加藻反复扰动下,Ca-P的含量持续降低,这表明藻类吸附同化了部分Ca-P.因此,在一定藻浓度条件下,可用沉积物中NH4Cl-P, AAP, %Ca-P的和来表征生物有效磷(BAP)含量.

Migration and transformation of phosphorus forms under dual effect of sediment resuspension and the addition of algae

Migration and transformation of phosphorus forms was investigated under repeated sediment resuspension with and without the addition of algae. The sediments and overlying water were obtained from Meiliang Bay of Tai Lake. The results show that the concentrations of dissolved total phosphorus (P) in the overlying water increased by 75%, 62.5% and 18.8% under static conditions, sediment resuspension and sediment resuspension with the addition of alge, the concentrations of dissolved inorganic P under sediment resuspension and sediment resuspension with the addition of alge increased by 300% and 100%, the Ca-P decreased by 9mg/kg DW and 31mg/kg DW under sediment resuspension and sediment resuspension with the addition of alge, indicating that the release of dissolved total P and dissolved inorganic P depends on the reduction of Fe/Al-P and Ca-P in the sediments. It was attributed to sediment resuspension and algae assimilation. However, under low algae concentration, the assimilation of algae in P is lower than the readsorption of reoxidized Fe or other P binding matter, such as clays and CaCO3particles. This result was confirmed by the increase in algae available P (AAP) under sediment resuspension conditions with and without the addition of algae. Although it is difficult to measure the formation and reduction rate of AAP, AAP is a good predicator of the bioavailability of sedimentary P. The estimation of bioavailable P (BAP) in the sediments can be presented by the sum of NH4Cl-P, AAP, and %Ca-P at certain concentrations of algae owing to the assimilation of Ca-P under sediment resuspension conditions with the addition of algae.