| 深型水库沉积物-水界面磷释放时空特征与驱动机制：以丹江口水库为例 |
| 摘要点击 245 全文点击 5 投稿时间：2025-04-08 修订日期：2025-05-29 |
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| 中文关键词 深型水库 扩散通量 释放机制 内源贡献率 薄膜扩散梯度技术 高分辨率渗析技术 |
| 英文关键词 deep-water reservoir diffusive flux release mechanism endogenous contribution diffusive gradients in thin films （DGT） high-resolution dialysis （HR-Peeper） |
| DOI 10.13227/j.hjkx.202504090 |
| 作者 | 单位 | E-mail | | 张潇月 | 中国科学院生态环境研究中心区域环境安全全国重点实验室, 环境水质学重点实验室, 北京 100085 | xyzhang@rcees.ac.cn | | 刘杰 | 中国科学院生态环境研究中心区域环境安全全国重点实验室, 环境水质学重点实验室, 北京 100085 | | | 夏佩琦 | 中国科学院生态环境研究中心区域环境安全全国重点实验室, 环境水质学重点实验室, 北京 100085 | | | 唐文忠 | 中国科学院生态环境研究中心区域环境安全全国重点实验室, 环境水质学重点实验室, 北京 100085
中国科学院大学资源与环境学院, 北京 100049 | | | 习刚正 | 长江水资源保护科学研究所, 武汉 430051 | | | 付婷 | 长江水资源保护科学研究所, 武汉 430051 | | | 王超 | 长江水资源保护科学研究所, 武汉 430051 | | | 张洪 | 中国科学院生态环境研究中心区域环境安全全国重点实验室, 环境水质学重点实验室, 北京 100085
中国科学院大学资源与环境学院, 北京 100049 | hongzhang@rcees.ac.cn |
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| 中文摘要 |
| 沉积物磷释放是江河湖库富营养化的关键因子之一，其机制及调控是水体污染防控的关键. 因缺乏深型水库沉积物磷多时空尺度释放特征及其与浅型水库差异的系统性解析，以丹江口水库为对象，联合薄膜扩散梯度技术（DGT）与高分辨率渗析技术（HR-Peeper），结合季节性原位观测与文献综述分析，揭示了沉积物-水界面有效态磷（DGT-P）与溶解性磷酸盐（SRP）的时空分异规律及驱动机制. 结果表明，丹江口水库沉积物中ρ（DGT-P）和ρ（SRP）介于0.01~0.63 mg·L-1和0.01~0.72 mg·L-1，丰水期较枯水期增幅35%~210%，入库河口和下游深水区为热点区域，均值超过《地表水环境质量标准》湖库水质Ⅴ类标准的40%~70%，显著高于典型浅水湖库；垂向表层0~-20 mm波动最剧烈，变异系数达78%，呈“表层扩散活跃、中层富集显著、深层逐渐衰减”的特征；丰水期磷扩散通量[0.09 mg·（m2·d）-1]较枯水期高162%，可使沉积物由“磷汇”向“磷源”转变，保守估计磷释放对水体总磷负荷贡献率约为5%，但热点区域在丰水期贡献率可超过20%；深型水库磷释放主要由底层缺氧驱动的铁结合态磷还原溶解主导，而热分层强化了季节性差异，其通量及季节性响应通常高于浅型湖库. 研究揭示了深型水库内源磷释放的时空特征及机制，提出“空间分区-季节调控-形态靶向”的多维防控策略，可为同类水体水质管理提供科学依据. |
| 英文摘要 |
| Phosphorus （P） release from sediment represents one of the key drivers of eutrophication in lakes and reservoirs， yet the spatiotemporal dynamics and mechanisms of P release in deep-water reservoirs remain underexplored compared to shallow systems. This study systematically investigated the spatiotemporal heterogeneity and driving mechanisms of sediment-water interface （SWI） P release in Danjiangkou Reservoir， a strategic deep-water reservoir in China， by integrating seasonal in situ observations， diffusive gradients in thin films （DGT）， and high-resolution dialysis （HR-Peeper） techniques. The results revealed that the effective phosphorus （DGT-P） and soluble reactive phosphorus （SRP） concentrations ranged from 0.01-0.63 mg·L-1 and 0.01-0.72 mg·L-1， respectively， with wet-season averages exceeding 40%-70% of China's Class V reservoir water quality standard. It was significantly higher than that of typical shallow lakes. Significant spatiotemporal heterogeneity of DGT-P and SRP concentrations was identified， with an increase of 35%-210% during the wet season， of which the inlet estuary and downstream deep-water area were the hot spots. Vertical profiles exhibited a “surface-active diffusion， mid-layer enrichment， and deep-layer attenuation” pattern， with the 0--20 mm sediment layer showing the highest variability （coefficient of variation： up to 78%）. Sediment P diffusion flux surged by 162% during the wet season [0.09 mg·（m2·d）-1]， driven primarily by iron-bound phosphorus （Fe-P） reductive dissolution under persistent bottom anoxia， exacerbated by thermal stratification. It could lead to a possible shift from “phosphorus sinks” to “phosphorus sources” of sediments. Conservative estimates indicated that sediment P release contributed 5% to the reservoir's total phosphorus （TP） load， yet localized contributions exceeded 20% in deep-water zones during the wet season， amplifying eutrophication risks. The flux and seasonal response were usually higher than that of shallow reservoirs due to the intensified seasonal differences by thermal stratification. Comparative analysis highlighted mechanistic distinctions between deep- and shallow-water systems： deep reservoirs relied on redox-controlled Fe-P release， whereas shallow systems were dominated by organic phosphorus （Org-P） and calcium-bound phosphorus （Ca-P） regulated by physical disturbances. To mitigate these risks， a multidimensional management framework of spatial zoning-seasonal regulation-morphological targeting was proposed， emphasizing priority control of hypoxia-prone deep zones and estuaries， optimized reservoir operation to disrupt thermal stratification， and dynamic seasonal monitoring. This study advances the mechanistic understanding of endogenous P release in deep-water ecosystems and provides actionable strategies for safeguarding water quality in strategic reservoirs. |
