| 摘要: |
| 借助微氧电极测试技术对太湖贡湖湾试验区疏浚后的新生界面溶解氧动态进行一年的跟踪调研，分析溶解氧在新生微米级界面的分布特征、扩散通量以及界面附近有机质矿化速率.结果表明疏浚后半年内，溶解氧在表层沉积物的侵蚀深度增大，氧化层明显加厚.氧气在新生界面表层沉积物中呈指数下降，但衰减相对较缓.在连续一年的跟踪调查中发现，仅秋季新生界面附近溶解氧浓度明显高于对照，而在其他月份无差异.污染底泥疏浚后一个月内氧扩散通量及有机碳矿化速率下降最为明显，仅为疏浚前的13%，其他月份沉积物-水界面氧的扩散通量、氧气的消耗速率、有机碳的降解速率均有不同程度下降，疏浚后新生界面氧气交换速率下降以及由此导致的有机碳矿化过程变缓可能深刻影响界面生源要素的迁移过程. |
| 关键词: 沉积物 新生界面 氧气 微电极 疏浚 太湖 贡湖湾 |
| DOI：10.18307/2018.0604 |
| 分类号: |
| 基金项目:国家自然科学基金面上项目（41673123）和天津市科技计划项目（16YFXTSF00550）联合资助. |
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| Dissolved oxygen dynamic across the new-born interface of bottom water and sediment after dredging contaminated sediment |
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GU Xiaozhi1, JIANG Weihua2
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1.State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, P. R. China;2.Wujin Forest Protection Station, Changzhou 213161, P. R. China
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| Abstract: |
| Oxygen dynamic had been conducted a yearlong investigation to obtain oxygen distribution, oxygen diffusion flux and mineralization rate of organic matter across the new-born interface of bottom water and sediments due to dredge. The results showed that oxygen penetration depth increased with thickening oxidation layer in new-born sediments. Oxygen concentrations decreased rapidly with depth in the sediments, but relatively moderate. Below the penetration depth, the O2 concentration inside the sediment was under the detection limit (approximation for 0). Oxygen concentration in bottom water in autumn was significantly higher in dredge treatment than those in control, however, there was not statistically significant among the three sampling during the investigation. The diffusive O2 flux (FO2) and the oxygen consumption rate (RO2) were observed based on O2 microprofiles, otherwise, organic carbon degradation rates (Rorg) were obtained from the oxygen consumption rate based on the modified Redfield ratio (O2/Corg=170/117) and the values also obviously decreased. Therefore, thickening oxidation layer and slowdown organic carbon degradation rates could significantly influence nutrients biogeochemical cycle after dredge. |
| Key words: Sediment new-born interface oxygen microelectrode dredge Lake Taihu Gonghu Bay |
