摘要
目前普遍认为磷铁耦合关系是P迁移的主要机制,但大部分研究结果并未提供直接的原位证据.为了探索沉积物剖面磷(P)与铁(Fe)的耦合关系,利用Zr O-Chelex薄膜扩散梯度技术(ZrO-Chelex DGT),分别对太湖、巢湖、鄱阳湖和洞庭湖4个浅水湖泊沉积物有效态Fe和P进行高分辨采样和分析.结果表明,不同湖区有效态Fe和P浓度在沉积物-水界面处开始增加,之后波动变化,垂向异质性较强,但两者浓度变化同步.有效态P和Fe浓度的相关分析结果证明两者浓度具有显著的线性相关.室内厌氧培养实验进一步表明,Fe^(3+)的还原性促使Fe^(2+)与铁结合态磷的释放,促使DGT有效态P与Fe同步变化.该结果表明沉积物P的二次迁移和释放受Fe氧化还原过程的控制,为铁磷耦合关系提供了直接证据.
It is universally accepted that the coupling relationship between phosphorus（ P） and iron（ Fe） is responsible for the migration of P,but there is little direct in situ evidence. In order to investigate the coupling relationship between P and Fe in sediments of shallow lakes,the concentrations of labile P and Fe in the sediments in Lakes Taihu,Chaohu,Poyang and Dongting were measured using ZrO-Chelex diffusive gradients in thin films（ ZrO-Chelex DGT）. The results showed that both labile Fe and P began to increase downward below the sediment-water surface followed by fluctuation up to the bottom of the sediment profiles. Their changes were consistent along the profiles,which were further supported by the positively linear correlations among them. Anaerobic incubation experiment further showed that the reductive dissolution of iron oxides led to the releases of ferrous Fe and P associated with iron oxides. The results proved that the remobilization of P in sediments was dominated by Fe redox.
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2017年第5期1103-1111,共9页
Journal of Lake Sciences
基金
国家水体污染控制与治理科技重大专项(2012ZX07103-005)资助
关键词
沉积物
薄膜扩散梯度
铁磷耦合
内源
有效性
长江中下游
Sediment
diffusive gradients in thin films
Fe-P coupling
internal loading
availability
middle and lower reaches of Yangtze River
