选择太湖不同营养类型的湖区开展了沉积物磷形态与磷吸附行为的研究,结果表明,位于藻型湖区梅梁湾的T1点表层沉积物中的总磷(TP)含量高于位于草型湖区T2点的相应值,且沉积物吸附能(K)值与TP含量显著负相关(p〈0.05),即沉积物自身的高磷含量可加速磷向水柱释放的风险。有机质与磷吸附饱和度(DPS)显著正相关(p〈0.05),同时DPS与K值显著负相关(p〈0.05),总之,有机质通过沉积物磷吸附饱和度间接的影响沉积物磷吸附行为。T2点沉积物吸附解吸平衡浓度(EPC0)值随深度递增,大型水生植物的存在促使表层沉积物维持磷汇的功能,T1点沉积物距表层10~15cm处EPC0值最低,故相应疏浚深度宜为10~15cm,这一结果为富营养化湖泊的修复提供了理论依据与技术参数。
Typical zones with different trophic states were selected to study fractions and sorption behaviors of phosphorus in sediment of Lake Taihu,China.Results showed that the surface sediment sampled at Site T1 in the Meiliang Bay as a typical area dominated by algae had a higher content of total phosphorus(TP) relative to that at Site T2 in the Xukou Bay as a typical area dominated by macrophyte.Additionally,there existed a significantly negative relationship between phosphorus sorption energy(K) and TP content(p 0.05).Hence high phosphorus loading would increase risk of its release from sediment into water column.Furthermore,organic matter(OM) content was found to be positively related to the degree of phosphorus sorption saturation(DPS)(p 0.05),coupled with a significantly negative relationship between DPS and K value(p 0.05) in the sediment.In short,OM can indirectly affect phosphorus sorption behaviors by adjusting DPS in sediment.In sediment of Site T2,equilibrium phosphorus concentration(EPC0) increased with depth,it meant that macrophyte existed there kept surface sediment to still function as phosphorus sink.While,in the sediment of Site T1,the EPC0 showed the lowest value at subsurface layer(10—15 cm),which may serve as a suitable depth for sediment dredging.The results provided a theoretical basis and technical parameters for restoration of eutrophic lakes.