模拟水位下降与刈割对高寒湿地土壤氨氧化与反硝化微生物的影响

发布时间：2018-05-25 14:34

本文选题：水位下降 + 氨氧化细菌　；参考：《农业环境科学学报》2017年11期

【摘要】：湿地土壤是温室气体重要的源和汇,认识湿地生态系统氮循环过程有助于预测氮循环对未来气候变化的响应与反馈机制。为探讨硝化作用和反硝化作用对土壤水位变化和刈割的响应机制,依托于2013年在青藏高原东部若尔盖泥炭地南部湿地设置的野外实验,通过在样地周围挖掘不同深度的排水沟模拟水位下降,结合刈割处理,研究水位下降和刈割对泥炭地土壤氨氧化古菌(Ammonia-oxidizing archaea,AOA)、氨氧化细菌(Ammonia-oxidizing bacteria,AOB)和反硝化细菌(Denitrifying bacteria)丰度的影响。2014年7月取样分析结果表明:水位下降显著降低土壤含水量,水位下降与刈割均显著降低土壤呼吸;氨氧化及反硝化微生物功能基因丰度在各处理间无显著差异,但刈割及其与水位下降的交互作用显著影响AOA-amo A与AOB-amo A基因丰度比。刈割处理显著增加AOB-amo A基因相对丰度,但对AOA-amo A基因丰度无显著影响,揭示AOB可能在湿地土壤硝化过程中占主导地位。土壤nir S基因丰度显著高于nir K基因,表明nir S基因对水位下降及刈割的响应更为敏感。随着土壤水位的下降,刈割促进了由AOB主导的氨氧化过程,而反硝化微生物丰度的增加削减了氨氧化产物硝酸盐的积累,继而降低了土壤硝酸盐含量。
[Abstract]:Wetland soil is an important source and sink of greenhouse gases. Understanding the process of nitrogen cycling in wetland ecosystem is helpful to predict the response and feedback mechanism of nitrogen cycle to future climate change. In order to investigate the response mechanism of nitrification and denitrification to soil water level change and mowing, a field experiment was conducted in 2013 in the southern part of the Zoige peat land in the eastern part of the Qinghai-Tibet Plateau. By digging ditches of different depths around the sample plots to simulate the water level decline, combined with cutting treatment, The effects of water level drop and mowing on the abundance of Ammonia-oxidizing archaeaAOAA, Ammonia-oxidizing bacterium AOBand denitrifying bacteria in peat soil were studied. There was no significant difference in the abundance of microbial functional genes in ammonia oxidation and denitrification between different treatments, but mowing and its interaction with water level significantly affected the abundance ratio of AOA-amo A and AOB-amo A genes. Mowing treatment significantly increased the relative abundance of AOB-amo A gene, but had no significant effect on the abundance of AOA-amo A gene, suggesting that AOB may play a dominant role in the process of soil nitrification in wetlands. The abundance of nir S gene in soil was significantly higher than that in nir K gene, indicating that nir S gene was more sensitive to water level decline and cutting. With the decrease of soil water level, mowing promoted the ammonia oxidation process led by AOB, while the increase of denitrification microbial abundance reduced the nitrate accumulation of ammonia oxidation products, and then decreased the nitrate content in soil.
【作者单位】：中国科学院生态环境研究中心;中国科学院大学;南京大学生命科学学院;
【基金】：国家重点基础研究发展规划(973)项目(2013CB956300) 国家自然科学基金项目(41371265)~~
【分类号】：S154.3

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