反复扰动下磷在沉积物和悬浮物以及上覆水间的交换

以太湖梅梁湾和月亮湾沉积物为研究对象,分析了沉积物反复扰动下磷在沉积物、悬浮物、上覆水间的交换规律.结果表明,反复扰动下,上覆水中TP和PP浓度降低;DTP则是在第8 d达到平衡浓度,分别稳定在0.019 mg·L-1(梅梁湾)和0.039 mg·L-1(月亮湾);DIP则发生了释放,随后降低,DIP的释放主要与沉积物中NH4Cl-P含量最大有关.第8 d达到平衡浓度,分别稳定在0.013 mg·L-1(梅梁湾)和0.028 mg·L-1(月亮湾).与上覆水中溶解氧的变化规律吻合.另外,扰动过程中梅梁湾上覆水DTP和DIP均明显高于月亮湾.由于扰动作用,悬浮物和沉积物上不同形态磷(NH4Cl-P、Fe/Al-P、HCl-P)数量分布发生明显变化.扰动过程中,梅梁湾悬浮物上NH4Cl-P、Fe/Al-P、HCl-P含量逐渐降低,而同一时间段上覆水中不同形态磷含量同样降低,但沉积物上NH4Cl-P、Fe/Al-P、HCl-P含量逐渐增加.尽管月亮湾的趋势不如梅梁湾显著,但总体趋势一致,暗示悬浮物在磷交换过程中所起的媒介作用.

Phosphorus Exchange Between Suspended Solids Sediments Overlying Water Under Repeated Disturbance

The variation of phosphorus (P) exchange between suspended solids, sediments and overlying water under repeated disturbance was investigated, with the sediments from Meiliang Bay (MLB) and Moon Bay (MB) as materials. The results showed that the concentrations of total P (TP) and particulate P (PP) decreased under repeated disturbance. Dissolved total P (DTP) reached equilibrium at 8 d, and was kept at 0.019 mg·L^-1(MLB) and 0.039 mg·L^-1(MB). On the contrary, dissolved inorganic P (DIP) increased in the overlying water, due to the highest concentration of NH₄Cl-P in the sediments, and then decreased. It reached equilibrium at 8 d, and was kept at 0.013 mg·L^-1(MLB) and 0.028 mg·L^-1(MB). It was coincided with the variation of DO. In addition, the concentrations of DTP and DIP in MLB were higher than those of MB under repeated disturbance. The distribution of P forms (NH₄Cl-P, Fe/Al-P, HCl-P) changed due to repeated disturbance. During the repeated disturbance, the concentrations of NH₄Cl-P, Fe/Al-P and HCl-P decreased gradually. At the same time, the concentrations of TP, PP, DTP and DIP decreased in the overlying water, but the NH₄Cl-P, Fe/Al-P, HCl-P increased in the sediments gradually. The trend in MB was not obvious, but the trend was the same as MLB. The results suggested that suspended solids were the medium in the phosphorus exchange between sediments and overlying water under repeated disturbance.