| 胡星云,白军红,温晓君,卢琼琼,王伟,王大伟.重金属镉添加对珠江河口农村和城市河流湿地土壤氮矿化过程的影响[J].农业环境科学学报,2019,38(3):618-626. |
| 重金属镉添加对珠江河口农村和城市河流湿地土壤氮矿化过程的影响 |
| Effects of Cd addition on nitrogen mineralization processes of rural and urban river wetland soils in the Pearl River Estuary, China |
| 投稿时间：2018-12-06 |
| DOI：10.11654/jaes.2018-1532 |
| 中文关键词: 有机氮矿化 镉 湿地土壤 脲酶 硝化细菌 珠江河口 |
| 英文关键词: Organic nitrogen mineralization Cd Wetland soils Urease enzymes nitrifiers The Pearl River Estuary |
| 基金项目:北京师范大学学科交叉建设项目 |
| 作者 | 单位 | E-mail | | 胡星云 | 水环境模拟国家重点实验室, 北京师范大学环境学院, 北京 100875 | | | 白军红 | 水环境模拟国家重点实验室, 北京师范大学环境学院, 北京 100875 | junhongbai@163.com | | 温晓君 | 水环境模拟国家重点实验室, 北京师范大学环境学院, 北京 100875 | | | 卢琼琼 | 水环境模拟国家重点实验室, 北京师范大学环境学院, 北京 100875 | | | 王伟 | 水环境模拟国家重点实验室, 北京师范大学环境学院, 北京 100875 | | | 王大伟 | 水环境模拟国家重点实验室, 北京师范大学环境学院, 北京 100875 | |
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| 中文摘要: |
| 以珠江河口农村河流湿地和城市河流湿地为研究对象，通过40 d室内培养实验研究了不同浓度的镉添加条件下（A：无添加；B：低浓度，15 mg·kg-1；高浓度，100 mg·kg-1）两类湿地土壤中有机氮的矿化过程，探讨了土壤关键酶、微生物及环境因子对有机氮矿化过程的作用机理。结果表明，不同浓度镉添加条件下两类湿地土壤的矿化速率均表现为初期波动较大而后期趋于稳定的变化趋势，且在40 d培养期内城市河流湿地土壤有机氮的矿化速率总体上大于农村河流湿地土壤；镉添加对培养初期有机氮的矿化具有促进作用，随着培养时间的延长，镉浓度增加抑制了农村河流湿地土壤有机氮的矿化，而低浓度镉却有利于城市河流湿地土壤有机氮的矿化；在培养期内两类湿地土壤有机氮的矿化速率均出现负值。土壤有机氮矿化与脲酶活性具有显著相关性（P<0.05），重金属镉添加抑制了农村河流湿地土壤的脲酶活性，但在培养后期低浓度镉添加却促进了城市河流湿地土壤的脲酶活性。氨氧化古菌（AOA）在不同浓度镉添加下两种湿地土壤的氨氧化过程中都占据很高比例（农村：95.37%~97.86%；城市：52.13%~78.15%），表明其较氨氧化细菌（AOB）更能适应复杂的环境。随着珠江口工业化和城市化的快速发展，当镉污染超出了农村和城市河流湿地土壤的纳污能力时（尤其是农村），会抑制脲酶和硝化微生物活性，进而对有机氮的矿化过程造成不利影响。 |
| 英文摘要: |
| Organic nitrogen mineralization of rural and urban river wetland soils from the Pearl River Estuary under different concentrations of Cd solution (A:control; B:low concentration addition, 15 mg·kg-1; C:high concentration addition, 100 mg·kg-1) were investigated using a 40-day laboratory incubation experiment. Furthermore, the effects of urease enzymes, nitrification microorganisms, and environmental factors on organic nitrogen mineralization were also analyzed. Our results showed that the rates of nitrogen mineralization of rural and urban river wetland soils under different levels of Cd treatments showed large fluctuations at the initial stage but remained stable during the late stage, and the mineralization rates of urban river wetland soils were higher than those in rural river wetland soils over the 40 days of incubation. Cd addition exhibited a stimulating effect on nitrogen mineralization at the early stage. With increasing incubation time, nitrogen mineralization of rural river wetland soils was inhibited with increasing Cd levels, while low level addition of Cd improved the rates of nitrogen mineralization of urban river wetland soils. The mineralization rates of the two types of wetland soils decreased, or even exhibited negative values, during the incubation period, which was mainly associated with an insufficient supply of substrates and with microbial nitrogen fixation and denitrification. Nitrogen mineralization rates were significantly correlated with urease activities (P<0.05). The addition of Cd inhibited urease activity in rural river wetland soils, but low levels of Cd enhanced urease activity of urban river wetland soils during the late stages of incubation. Ammonia oxidizing Archaea (AOA) undertook a large proportion of ammoxidation in rural river wetland soils (95.37%~97.86%) and urban river wetland soils (52.13%~78.15%) under different levels of Cd addition, and these are more adaptable to a pollution-stressed environment than ammonia oxidizing bacteria (AOB). With rapid development of industrialization and urbanization in the Pearl River Estuary, once Cd pollution exceeds the capacities of rural and urban river wetland soils (especially in rural river wetlands), enzyme and microbial activities are inhibited, prohibiting nitrogen mineralization of wetland soils in the long term. |
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