三江平原典型湿地植物枯落物中汞的变异特征

Variance of mercury in typical plant litters in Sanjiang Plain Wetland

在野外进行现场实验 ,研究了 2种典型湿地植物枯落物经一个生长季的分解后汞的变化 ,并探讨了其影响因素 .在实验的 3 0d后 ,2种湿地大部分层次植物枯落物汞的浓度表现为先升高 ,随后降低 ,最后又明显升高 .枯落物分解程度影响着汞浓度的变化 .前 90d枯落物质量减少快 ,且汞的浓度降低 ,枯落物中的汞以损失为主 ,后期因植物残体吸附汞的能力增强 ,汞损失减少 .汞的损失率和水中溶解性汞的浓度呈显著负相关关系 .在 2 0cm和 3 0cm深度上 ,枯落物汞的损失率与积水深度和地温都具有显著相关关系 (P <0 0 5 ) .

In the field experiment, temporal variance of mercury of two typical wetlands vegetal litters was researched and the affecting factors were discussed. Mercury concentration of most layers in two litters increased after 30 days, then decreased, and increased at last in the decomposition during a growth season. The variance of mercury concentration was related to the degree of the litters decomposition. At the initial 90 days, the mass of the litter lost quickly, and mercury concentration decreased, so much mercury in litters was lost. The loss of mercury was little at last stage because of the increasing ability of adsorption to mercury. In the depth of 20cm and 30cm, loss of mercury correlated significantly with the depth of inundated water and soil temperature (P<0.05). The difference of microenvironment, especially the change of inundation, affected on the mercury loss of Carex lasiocarpa litters more than Calamagrostis angustifolia litters in different depth.