The differential effects of sand burial on CO2, CH4, and N2O fluxes from desert biocrust-covered soils in the Tengger Desert, China
The differential effects of sand burial on CO2, CH4, and N2O fluxes from desert biocrust-covered soils in the Tengger Desert, China
复制标题
沙埋对中国腾格里沙漠生物结皮覆盖土壤CO2、CH4和N2O通量的差异影响
DOI：
10.1016/j.catena.2017.09.031
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发表时间：
2018-01-01
期刊：
影响因子：
6.2
通讯作者：
Gao, Yanhong
中科院分区：
文献类型：
--
作者：
Jia, Rongliang;Teng, Jialing;Gao, Yanhong
生物结皮是沙漠生态系统的重要组成部分，当它们覆盖土壤时，在温室气体通量中起着重要作用。然而，鲜为人知的是，是否以及如何沙埋，最常见的干扰影响生物结壳的生物多样性和生态功能，影响CO2，CH4，和N2O从沙漠生物结壳覆盖的土壤通量。根据对两种生物结皮覆盖的土壤中三种温室气体通量的测定，近50%的藻类覆盖率和50%的地衣覆盖率，这里蓝细菌被分类为藻类）和苔藓（即，100%覆盖率的Didymodon vinealis（Brid.）Zand.）在腾格里沙漠东南缘的沙坡头，分别设置了0（对照）、1 mm（浅埋）和10 mm（深埋）沙埋，研究了短期（20 d）和较长时间（1 a）沙埋对3种温室气体通量的影响及其与土壤温度和水分的关系。结果表明，沙埋对两种生物结皮覆盖土壤的CO2排放通量有显著的正效应，对CH4吸收有显著的负效应（P < 0.05），但对N2O排放通量的影响因埋深而异。浅埋显著增加了生物结皮覆盖土壤的N2O排放（P < 0.05），而深埋则相反。随着埋藏时间的延长，CO2排放量的增加幅度减小，而CH4和N2O排放量的变化则因生物壳类型和埋藏深度而异。结果表明，两种生物结皮的CO2通量与土壤温度和水分密切相关，随5 cm土壤温度的升高和沙埋引起的土壤水分的增加而增加。相比之下，CH4和N2O的排放量没有明显的温度或湿度。总体而言，沙埋导致的全球变暖潜势增加表明，这种沉积可能会加剧生物结壳覆盖的沙漠地区的温室效应。
Biocrusts are a crucial component of desert ecosystems, playing a significant role in greenhouse gas fluxes when they cover soils. However, little is known about whether, and how sand burial, one of the most common disturbances affecting the biodiversity and ecological function of biocrusts, influences fluxes of CO2, CH4, and N2O from the desert biocrust-covered soils. Based on measurements of the fluxes of three greenhouses gases from soils covered with two kinds of biocrusts separately dominated by mixed (i.e., approximately 50% algal coverage and 50% lichen coverage of Endocarpon pusillum Hedw., here cyanobacteria are classed as algae) and moss (i.e., 100% coverage of Didymodon vinealis (Brid.) Zand.) crusts respectively, followed by zero (control), 1 mm (shallow burial), and 10 mm (deep burial) burial depths of sand, we studied the effects of short (20 days) and relatively long periods (one year) of sand burial on the fluxes of three greenhouse gases as well as their relationships with soil temperature and moisture at Shapotou on the southeastern edge of the Tengger Desert. The results of this study showed that sand burial had a significantly positive effect on emission fluxes of CO2 and a negative effect on uptake of CH4 by soils covered with the two types of biocrusts (P < 0.05), but had a differential effect on N2O fluxes depending on burial depth. Shallow burial dramatically increased N2O emissions from the biocrust-covered soils (P < 0.05), but the opposite was observed under deep burial. As burial time increased, the increase of CO2 emissions decreased, but changes in fluxes of CH4 and N2O varied with biocrust types and burial depths, respectively. In addition, results showed that CO2 fluxes from the two biocrusts were closely related to soil temperature and moisture; thereby increased with the raised soil temperature at 5 cm depth and soil moisture caused by sand burial. In contrast, CH4 and N2O emissions were not clearly related to temperature or moisture. Overall, the increase in global warming potential caused by sand burial indicates that this kind of deposition may aggravate the greenhouse effect of desert areas covered with biocrusts.