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题名: 太湖流域源头溪流温室气体释放特征
作者: 袁淑方
学位类别: 硕士
答辩日期: 2012
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 王为东
关键词: 人类活动 ; human activities ; 污染负荷 ; pollution load ; 温室气体释放 ; greenhouse gas emission ; 生态恢复效应 ; ecological restoration effect
其他题名: Greenhouse Gas Emission Characteristics of a Headstream in Taihu Lake Basin
中文摘要:       江河水系与其周围环境共同变化,人类活动对河流的扰动将造成河流内部物理、化学及生物过程的改变。以水利工程、生活及工业污染的排入、农田径流输入为主的人类活动不可避免将导致河流生态系统的破坏。河流恢复生态工程通过恢复河流天然形貌、改变水流条件及河道结构的方式引导河流生态系统功能的修复。太湖上游农村面源污染严重,对下游水体水质影响恶劣。本研究选取太湖流域上游源头溪流——南苕溪为对象,研究流域土地利用变迁背景下河流水质污染特征,探索研究受污染河流水体温室气体N2O、CH4和CO2排放通量时空分布特征。同时,进行水体修复生态工程措施效应研究。研究结果表明: 1)受污染河流是温室气体N2O、CH4和CO2的排放源。河流水体N2O、CH4和CO2时空变异较大,饱和度范围分别为55.8%-1286%、49.9%-7921%和39.5%-1992%,平均溶存浓度分别为1.18 ± 0.24 μg-N/L(492%)、0.0178 ± 0.0012 mmol/L(379%)和74.8 ± 6.3 mmol/L(511%)。三者通量分别为−105.1-252.9 μg-N/m2·h、−0.67-209.9 mg/m2·h和−480.6-756.4 mg/m2·h。时间上,N2O、CH4和CO2溶存与通量峰值段均发生在4-7月。此时梅汛期持续降雨造成大量径流污染输入河道内部,为河流污染负荷峰值段,造成河流水环境与水质的恶化。空间上,中游农田区及下游河口区为污染较重河段,相应N2O、CH4和CO2饱和度或通量较高。河流营养负荷增加造成微生物活性强化,N2O、CH4和CO2产量增加。此外污染水体同时可直接输入大量N2O、CH4和CO2。因此,河流温室气体含量与通量因河流污染输入显著增加。 2)河口生态工程具有较好的水质净化效应:河流溶氧、pH及电导率得到较好改善;河流氨态氮、亚硝态氮、总磷、活性磷及悬浮颗粒物去除率分别为43.7%、21.2%、36.7%和28.1%;河流总氮、总磷、COD和TOC被生态潜坝拦截;包括N2O、CH4和CO2在内的温室气体溶存含量去除率分别为42%、50%和52%,从而较好地保障了入青山湖库区水体的水质。
英文摘要:       Rivers and streams change concurrently along with surrounding environment. Anthropogenic activities in watershed will alter the physical, chemical and biological processes in stream. Human disturbance such as hydraulic engineering, municipal and industrial wastes inputs and agricultural runoff might lead to the destruction of river ecosystems. River ecological engineering can induce the restoration of river ecosystems functioning by recovering natural river morphology, changing stream flow and reconstructing river corridor. Nonpoint source pollution in upper stream in Taihu Lake Basin is turning more severe, which leads to the deterioration of water quality in downstream reach. South Tiaoxi River, a headwater stream in the upper reach of Taihu Lake Basin, was chosen to study the pollution characteristics under land use shift through the watershed and to explore the dissolved contents and emission rates of N2O, CH4 and CO2 in polluted water body. Restoration effects of ecological engineering were also studied. Our findings are as follows. 1) Polluted river can be significant sources of greenhouse gases such as N2O, CH4 and CO2. South Tiaoxi River showed distinct characteristics in the distribution and emission of greenhouse gases. N2O, CH4 and CO2 varied greatly over temporal and spatial scale, with saturation ranges of 55.8 % - 1286 %, 49.9 % - 7921 % and 39.5 % - 1992 % respectively, while the average dissolved concentrations were 1.18 ± 0.24 μg-N/L (492 %), 0.0178 ± 0.0012 mmol/L (379 %) and 74.8 ± 6.3 mmol/L (511 %). The emission rates of these three gases ranged from -105.1 to 252.9 μg-N/m2·h, -0.67 to 209.9 mg/m2·h and -480.6 to 756.4 mg/m2·h respectively. Temporally, peaks for either the dissolved contents or emission rates of N2O, CH4 and CO2 all happened during the period between April and July. It was just in plum rain flood season with peak pollution when persistent rainfall resulted in strong runoff carrying great amount of pollutants which entered the stream, causing worse water environment condition and water quality. Spatially, river stretch in farmland region of middle reach and confluence region of downstream reach were more polluted, accordingly N2O, CH4 and CO2 saturation and emission rates there were higher. It turned out when nutrients load increased in the river, microbial activities were enhanced, leading to increased production of N2O, CH4 and CO2, even if the generation mechanism for each gas varied. Along with direct input of N2O, CH4 and CO2 in entering water, the contents and emission rates of these greenhouse gases raised significantly when stream pollution increased. 2) Ecological rehabilitation engineering in the confluence area could purify the running water well, with dissolved oxygen and pH increased and electric conductivity decreased; ammonium, nitrite, total phosphorous, phosphate and total suspended sediment were also removed significantly with removal rates of 43.7%, 21.2%, 36.7% and 28.1% respectively while total nitrogen and organic matter were well retained downstream. Dissolved concentration of green house gases like N2O, CH4 and CO2 also dropped by 42%, 50% and 52% respectively in confluence. Thus better water quality of stream water entering downstream reservoir was promised.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/35161
Appears in Collections:环境水质学国家重点实验室_学位论文

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Recommended Citation:
袁淑方. 太湖流域源头溪流温室气体释放特征[D]. 北京. 中国科学院研究生院. 2012.
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