丹江口水库是南水北调中线工程的水源地，其水质状况关系着中线调水工程沿线地区的用水安全。水库消落区湿地是水体与陆地之间的过渡带，具有较为丰富的生物多样性和独特的生态服务功能。丹江口水库消落区湿地是控制库区污染入库的最后一道防线，对于削减非点源污染物入库总量、保障水库水质安全起着非常重要的作用。
中科院武汉植物园刘文治博士、张全发研究员和刘贵华研究员通过吸附-解吸附实验发现，丹江口水库消落区湿地的土壤具有较高的磷吸附容量，每千克土壤的最大磷吸附值可达771.3 mg，但秋冬季水位的上升会导致24.11%的土壤吸附磷重新释放到水体中去。通过乙炔抑制-气相色谱实验，刘文治等还发现消落区湿地不同植物群落土壤的反硝化能力存在着显著性的差异，水蓼和藨草群落土壤的反硝化能力要显著高于其它群落。植物生物量、植被盖度与反硝化能力呈显著的正相关关系。
研究结果表明，丹江口水库消落区湿地具有较强的氮磷污染削减能力，植被条件对湿地去氮能力有显著影响。这也提示在大坝加高后植被重建过程中，可以通过对消涨带湿地植被的定向构建来增强湿地的去氮功能，以更好地保障丹江口水库的水质安全。（生物谷Bioon.com）
生物谷推荐原文出处：
Marine and Freshwater Research DOI:10.1071/MF09013
Phosphorus sorption and desorption characteristics of wetland soils from a subtropical reservoir
Wenzhi Liu , Guihua Liu , Siyue Li , Quanfa Zhang
Abstract
Water-level regulation results in alternating exposure and inundation of soils in reservoir fluctuation zones, which may significantly influence the phosphorus sorption and desorption processes in the soil. The present study investigated the phosphorus sorption and desorption properties of wetland soils in China's Danjiangkou Reservoir using a batch equilibrium technique. Results showed that the maximum phosphorus sorption ranged from 435 to 1429 mg kg-1, with an average of 771 mg kg-1. The maximum phosphorus sorption was found to be significantly related to amorphous iron (r = 0.883, P < 0.01) and pH (r = -0.333, P < 0.05), and the binding constant k was strongly correlated with the amorphous iron (r = 0.475, P < 0.01) and organic matter (r = -0.455, P < 0.01). The phosphorus desorption percentage varied from 8 to 44%, with a mean value of 24%. The present study implies that short-term inundation in reservoir fluctuation zones would result in soil phosphorus desorption to some extent, in spite of the considerable absorption ability in the exposure period. These results are useful for assessing the phosphorus retention capacity of wetland soils and optimising management strategies for water conservation in reservoir regions.
Keywords: Danjiangkou Reservoir, inundation, non-point source pollution, release risk, river regulation.
