模拟不同水位梯度对湖滨湿地底泥碳氮磷化学计量特征的影响

Effects of simulated different water table gradients on carbon, nitrogen and phosphorus stoichiometric characteristics of sediment in lakeside wetland

为阐明湖滨湿地土壤生态化学计量学特征与湿地淹水之间的差异响应,进行了不同水位(0、7、15 cm)及窄叶香蒲不同生长时期(生长初期、生长旺盛期和枯落期)的盆栽模拟试验,结合方差分析、相关性分析,探讨其对高原湖滨湿地底泥有机碳(SOC)、全氮(TN)、总磷(TP)以及生态化学计量特征的影响.结果表明:(1)底泥中SOC、TN、TP含量及生态化学计量比随不同水位梯度均呈显著差异(P<0.01);(2)随植物生长期,底泥中SOC、TP、C/N和C/P呈逐渐减小趋势,TN和N/P呈逐渐增大的趋势;(3)相关性分析表明,0、7和15 cm水位条件下的主控因子分别为DO、Eh和pH.研究表明,在15 cm淹水高度,更有利于底泥中生态系统的稳定,而相对在水深7 cm时,元素之间的耦合关系以及稳定性更低.

In order to clarify the differential response of ecological stoichiometric characteristics of lakeside sediment to wetland flooding,potted simulation experiment was conducted by setting up 3 water levels(0,7 and 15 cm)at Typha angustifolia which were grown in different growth periods(early growth,vigorous growth and senescent period).Parameters including soil organic carbon(SOC),total nitrogen(TN)and total phosphorus(TP)contents,and ecological stoichiometric characteristics of the sediments were measured and calculated,combined with variance analysis and correlation analysis.The results showed that:(1)SOC,TN and TP contents and ecological stoichiometric ratios of the sediments varied significantly along with different flooding depths(P<0.01).(2)SOC and TP contents,C/N and C/P of the sediments were on declining trends,while TN content and N/P gradually increased with the growth of cattails.(3)Correlation analysis showed that the main control factors under 0,7 and 15 cm water levels were dissolved oxygen,oxidation-reduction potential and pH,respectively.To summarize,flooding depth of 15 cm was more conducive to the stability of sediment ecosystem while the coupling relationship and stability between elements were weaker at the flooding depth of 7 cm.