摘要
基于薄膜梯度扩散(DGT)和平面光电极(PO)两种原位监测方法,首次从微米尺度获取了南四湖4个湖区泥—水界面(SWI)的活性磷以及亚铁(Fe^(2+))、亚硫(S^(2-))、pH和溶解氧(DO)等密切因子精细化分布变化信息,并初步探讨了南四湖SWI活性磷变化特征与控制机制。结果直观揭示南四湖底泥剖面活性磷的浓度分布呈现明显的空间异质性,变化范围为0.34~2.36 mg/L,均值为1.26 mg/L。水平空间分布上独山湖((1.41±0.56) mg/L)和昭阳湖((1.97±0.42) mg/L)活性磷浓度显著高于南阳湖((1.07±0.20) mg/L)和微山湖((0.58±0.24) mg/L)。南四湖大部分采样点底泥中的活性磷与活性硫、活性铁浓度呈现正相关性,而昭阳湖活性磷、活性铁、活性硫浓度的相关性尤为显著(P<0.001),表明在剧烈有机质矿化过程中,活性硫可以通过与铁的相互作用促进活性磷的释放。SWI界面pH和DO结果显示受上游大量有机质输入的影响,底泥有机质降解消耗大量DO并产生大量S^(2-),硫酸盐还原占据主导地位,促进铁结合磷的释放。以上结果表明南四湖底泥中磷的形态转化受铁和硫两类氧化还原敏感元素控制,支持了磷、铁、硫的耦合释放机制,明确了硫与铁的生物地球化学循环共同控制泥中活性磷的释放。
Herein the refined distribution of labile phosphorus(P)and its related factors,e.g.ferrous iron(Fe^(2+)),sulfide(S^(2-)),pH,and dissolved oxygen(DO)across the sediment-water interface(SWI)of Lake Nansi were simultaneously measured using two emergent in situ methods:diffusive gradient in thin films and planar optode.We further explored the characteristics and controlling mechanisms of labile P changes across the SWI of Lake Nansi.The distribution of labile P in the sediment profiles of Lake Nansi showed obvious spatial heterogeneity,ranging from 0.34 to 2.36 mg/L(average:1.26 mg/L).The horizontal spatial distribution of labile P was significantly higher in Lake Dushan((1.41±0.56)mg/L)and Lake Zhaoyang((1.97±0.42)mg/L)than in Lake Nanyang((1.07±0.20)mg/L)and Lake Weishan((0.58±0.24)mg/L).The positive correlation between labile P and labile S,Fe in the sediment of most of the sampling sites in Lake Nansi was observed,particularly in Lake Nanyang(P<0.001),indicating labile S can promote P release through interaction with Fe during intense organic matter mineralization.2D,high-resolution distribution of pH and DO indicated that the large amounts of organic matter from upstream affected the SWI,where the degradation of organic matter consumed large quantities of DO and produces large quantities of S^(2-),dominated by sulfate reduction,which promoted the release of Fe-bound P.The above results indicated that the migration of P in the sediment of Lake Nansi was controlled by two types of redox-sensitive elements,Fe and S,which supported the coupled release mechanism of P,Fe and S,and clarifies that the biogeochemical cycles of S and Fe jointly control the release of reactive P in the sediment.
作者
孙宇
郭心月
白洋
张云鹏
韩超
Sun Yu;Guo Xinyue;Bai Yang;Zhang Yunpeng;Han Chao(State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 211135,P.R.China;University of Chinese Academy of Sciences,Beijing 100049,P.R.China;College of Geography and Environmental Sciences,Zhejiang Normal University,Jinhua 321004,P.R.China;School of Civil and Architecture Engineering,Xi an Technology University,Xi an 710021,P.R.China)
出处
《湖泊科学》
北大核心
2025年第3期849-859,共11页
Journal of Lake Sciences
基金
国家重点研发计划政府间国际合作项目(2023YFE0100500)
国家自然科学基金项目(42277463)联合资助。
