| 摘要: |
| 【目的】评价水位变化对黄河中游滨河湿地土壤碳排放的影响程度并分析其影响机理。【方法】对研究区芦苇群落进行土壤CO2释放的随机调查，结合人工注水设置监测试验，研究了各种因素对土壤CO2释放的影响规律。【结果】水位变化的影响规律与土温有关，土温13~23 ℃时，随水位上升土壤CO2释放速率先升后降，最大值对应深度为0 cm，在24~30 ℃和>30 ℃时则逐渐降低，同时，水位与CO2释放回归方程的R2值也受到土温影响；野外样地半注水（水位-30 cm）和全注水（水位0 cm）设置后，土壤CO2释放速率呈急剧降低-波动滞后-波动同步的特征，所有数据白天和晚上释放平均值分别为3.05、2.74 μmol/(m2?s)，多表现为昼高夜低的规律，在7 d监测期间未干涉样地（Lo）、全注水（Lh）和半注水样地（Lf）CO2排放总量分别为2.47、1.22、1.39 mol/m2，后二者分别造成了50.4%和43.4%的减少。【结论】水位升降对湿地CO2释放的影响收到气温和昼夜变化的复合影响，较多情况下表现为水位上升，CO2释放减少，释放速率昼高夜低，水位变化造成CO2的影响持续时间大于7 d。 |
| 关键词: 水位变化；土壤呼吸；芦苇湿地 |
| DOI：10.13522/j.cnki.ggps.20180674 |
| 分类号: |
| 基金项目: |
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| The Effect of water level fluctuation in yellow river on CO2 emission from an adjacent wetland is modulated by soil temperature |
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LYU Haibo
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1.College of Environment and life science, Weinan Normal University, Weinan 714000, China; 2. Weinan Normal University,Key Laboratory for Eco-Environment of Multi-river Wetlands in Shaanxi Province, Weinan 714000，China
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| Abstract: |
| 【Objective】 Change in groundwater and soil moisture alters soil redox thereby shifting microbial activity and affecting soil emission. The objective of this paper is to experimentally elucidate how water level fluctuation in river could affect CO2 emission from adjacent wetland.【Method】The study area was a wetland with reed (Phragmites australis Trin. ex Steud) adjacent the Longmen-Tongguan section of the Yellow River. We did field survey on CO2 emission from the wetland and conducted water-injecting monitoring experiments to measure CO2 emission at different water level fluctuation patterns. 【Results】 The impact of water level fluctuation in the river on CO2 emission was modulated by soil temperature. When soil temperature was in 13~23℃, with the water level in the river rising, CO2 emission from the soil increased first followed by a fall with the maximum reaching when the water level was 0 cm. In contrast, when soil temperature rose to 24~30 ℃ or higher than 30 ℃, CO2 emission from the soil decreased as the water level in the river was rising. Regression analysis found that R2 of the regression varied with soil temperature, and the results from both half water injection (Lh, injected to -30 cm water level) and full water injection (Lf, injected to 0 cm water level) suggested that CO2 emission decreased sharply, followed by a fluctuation which lagged behind the water level fluctuation, before oscillated under the same frequency as the water-level in the river. Calculation from all data revealed that the average emission in daytime and night was 3.05 and 2.74 μmol/(m2?s) respectively. In the seven days of experiment, the total CO2 emission rate were 2.47, 1.22, 1.39 mol ·m-2 for the control (undisturbed soil sample), Lh and Lf, respectively.【Conclusion】The influence of water level fluctuation in the Yellow River on CO2 emission from an adjacent wetland was impacted by soil temperature and diurnal temperature. In most cases, a rise in water level led to a decrease in CO2 emission, and CO2 emission in daytime was higher than that in night. The impact of one water level fluctuation in the river on CO2 emission could last for more than a week. |
| Key words: water level fluctuation; soil respiration; reed wetland; Yellow River |
