长江中下游典型浅水湖泊沉积物-水界面磷与铁的耦合关系

发布时间：2018-07-02 12:46

本文选题：沉积物 + 薄膜扩散梯度　；参考：《湖泊科学》2017年05期

【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.
[Abstract]:At present, it is generally believed that the phosphorus-iron coupling is the main mechanism of P transport, but most of the results do not provide direct in situ evidence. In order to explore the coupling relationship between phosphorus (P) and iron (Fe) in sediment profile, the available Fe and P in four shallow water lakes, Taihu Lake, Chaohu Lake, Poyang Lake and Dongting Lake, were sampled and analyzed by ZrO-Chelex DGT (ZrO-Chelex DGT). The results show that the available Fe and P concentrations in different lakes begin to increase at the sediment-water interface, then fluctuate and have strong vertical heterogeneity, but the concentration changes synchronously. The correlation analysis of available P and Fe concentrations shows that there is a significant linear correlation between the two concentrations. Laboratory anaerobic culture experiments further showed that the reduction of Fe3 promoted the release of Fe ~ (2) from Fe ~ (2) and iron bound phosphorus, and promoted the simultaneous change of available P and Fe in DGT. The results show that the secondary transport and release of P in sediments are controlled by the Fe redox process, which provides direct evidence for the Fe-P coupling relationship.
【作者单位】：中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室;中国科学院大学;
【基金】：国家水体污染控制与治理科技重大专项(2012ZX07103-005)资助
【分类号】：X52

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