黄河二氧化碳逸出时空变化及其影响因素——以头道拐水文站为例

发布时间：2018-03-26 08:13

本文选题：二氧化碳逸出通量　切入点：时空变化　出处：《生态学报》2017年22期

【摘要】：河流连接着海洋碳库和陆地碳库,河流碳逸出是全球碳收支的重要组成部分。本文以黄河上游和中游分界点—内蒙古段头道拐断面为研究对象,采用Li-7000静态箱法监测了断面4个采样点在2013—2015年期间四季的CO_2逸出通量(FCO_2),并分析了FCO_2时空变化规律。基于研究断面主要水文和水化学指标的野外监测和室内分析结果,探讨了FCO_2的主要影响因素。结果表明断面FCO_2介于14—186 mol m~(-2)a~(-1),平均值为84 mol m~(-2)a~(-1);水体CO_2分压(p CO_2)介于467—2101μatm,平均值为995μatm;DOC浓度介于2.7—13 mg/L。FCO_2季节性差异明显:夏季FCO_2为全年最大456 mmol m~(-2)d~(-1),冬季最小33 mmol m~(-2)d~(-1)。FCO_2在4个采样点的空间差异显著:河道右岸S4点处最大为392 mmol m~(-2)d~(-1);河道中部S2和S3点基本相同;河道左岸S1点最小为86 mmol m~(-2)d~(-1)。FCO_2与河道流速呈现较好的正相关关系,与p CO_2中等相关,与p H负相关,与风速的相关性不明显,说明对于该研究断面河道流速较p CO_2对FCO_2的贡献更大。本研究较为精细地探讨了头道拐断面的水体CO_2逸出规律,表明即使在同一河道断面,FCO_2也可能存在较大空间差异,流速较大处的FCO_2较大,因此在野外监测FCO_2时需要在河道断面选取具有代表性的采样点,特别是较大的河流。研究结果为黄河中上游CO_2逸出量评价和河道断面FCO_2监测点的布设提供了科学依据。
[Abstract]:Rivers are connected to marine and terrestrial carbon reservoirs, and river carbon emission is an important part of global carbon budget. This paper studies the section of the head of Inner Mongolia section, which is the boundary point of the upper and middle reaches of the Yellow River. The Li-7000 static box method was used to monitor the CO_2 emission flux of four sampling sites in the four seasons of 2013-2015, and the temporal and spatial variation of FCO_2 was analyzed. Based on the field monitoring and indoor analysis results of the main hydrological and hydrochemical indexes of the section, The main influencing factors of FCO_2 are discussed. The results show that the cross section FCO_2 is between 14 and 186 mol / m ~ (-1) with an average value of 84 mol / m ~ (-1), and the partial pressure of water CO_2 / CO _ 2 is between 467-2101 渭 atm and the mean value is 995 渭 / m ~ (DOC) between 2.7-13 mg/L.FCO_2, and summer FCO_2 is the maximum mg/L.FCO_2 value of 456#en7# in the whole year. The spatial difference of minimum 33 mmol m~(-2)d~(-1).FCO_2 in winter at 4 sampling sites is significant: the maximum value at S4 point on the right bank of the river is 392 mmol / m ~ (-1), and the S _ 2 and S _ 3 points in the middle of the channel are basically the same. The minimum S1 point on the left bank of the river is 86 mmol m~(-2)d~(-1).FCO_2, which has a good positive correlation with the channel velocity, a moderate correlation with p CO_2, a negative correlation with pH, and no significant correlation with the wind speed. The results show that the channel velocity of the study section is more important to FCO_2 than p CO_2. In this study, the escape law of CO_2 in the water body of the head road section is discussed in detail, which indicates that there may be great spatial differences even in the same section of the river channel. The FCO_2 where the velocity is higher is larger, so it is necessary to select representative sampling points in the channel section when monitoring FCO_2 in the field. The results of the study provide scientific basis for the evaluation of CO_2 emission in the upper and middle reaches of the Yellow River and the layout of FCO_2 monitoring points for river sections.
【作者单位】：内蒙古大学生态与环境学院;新加坡国立大学;
【基金】：国家自然科学基金(91547110,51469018) 水利部公益性行业科研专项(20150104)
【分类号】：P332;P343.1

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