沉积物短期扰动下BAPP再生和转化机制

以太湖梅梁湾的沉积物和上覆水为材料,研究了沉积物不同扰动方式条件下,悬浮物中不同形态磷数量分布的变化特征,并且探讨了其对悬浮物中可被生物利用颗粒态磷(BAPP)的影响.结果表明,扰动使得上覆水中溶解性磷酸盐(DIP)的含量有所降低,与反复扰动相比,持续扰动作用下的下降幅度略大.试验期间,悬浮物中弱吸附态磷(NH4Cl-P)、钙结合态磷(Ca-P)与残余磷(Res-P)占总磷(Tot-P)的百分比平均值分别增加了2.97%、12.23%、4.09%(持续扰动)和3.53%、10.35%、2.07%(反复扰动),非闭蓄态铁铝结合态磷(Fe/Al-P)则分别下降了5.55%(持续扰动)、1.78%(反复扰动),说明扰动促进了易释放态磷向难释放态磷的转化.然而,悬浮物上BAPP含量却未相应降低,反而升高,分别从20.68%(初始状态)升高至49.27%(平均值,持续扰动)和57.92%(平均值,反复扰动).这表明单纯地以悬浮物中的NH4Cl-P、非闭蓄态Fe/Al-P等易释放态磷来估算BAPP是不合理的.

Regeneration and Transformation of BAPP in Suspended Solids Under Short-term Sediment Disturbance

The change of phosphorus forms in suspended solids under short-term sediment disturbance of different modes and its influence on BAPP in suspended solids were investigated, using sediments and overlying water from Meiliang Bay. The results showed that the concentrations of DIP in the overlying water decreased under disturbance. The concentrations of DIP under continuous disturbance were lower than those under intermittent disturbance. The NH₄Cl-P, Ca-P and Res-P concentrations increased by 2.97%, 12.23%, 4.09% under continuous disturbance and 3.53%, 10.35%, 2.07% under intermittent disturbance and the non-occluded Fe/Al-P decreased by 5.55% under continuous disturbance and 1.78% under intermittent in suspended solids during the experiment, indicating that sediment disturbance could promote the transformation of sedimentary phosphorus from mobile forms to refractory forms. According to the speculation, the content of BAPP should decrease. However, it increased from 20.68% (initial state) to 49.27% (average, under continuous disturbance) and 57.92% (average, under intermittent disturbance). This result indicated that it is problematic to estimate the BAPP using solely the mobile phosphorus forms, such as NH₄Cl-P and non-occluded Fe/Al-P.