| 引用本文: | 董彬,王立志,宋红丽,王国祥,刘艳.暴发生长期菹草(Potamogeton crispus)附着生物膜成为城市河流反硝化作用热点.湖泊科学,2023,35(1):145-154. DOI:10.18307/2023.0109 |
| Dong Bin,Wang Lizhi,Song Hongli,Wang Guoxiang,Liu Yan.Denitrification hotspots existed in the epiphytic biofilms on submerged macrophyte Potamogeton crispus during explosive growing stage in urban river. J. Lake Sci.2023,35(1):145-154. DOI:10.18307/2023.0109 |
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| 摘要: |
| 富营养化河流中水生植物丰富的浅水区通常是氮素转化的热区,沉水植物菹草暴发性生长可能会加速河流生态系统的反硝化进程,但菹草附着生物膜的反硝化作用变化特征及其脱氮贡献尚不清楚。为探究菹草暴发生长期间附着生物膜的反硝化作用潜力及环境效应,以沂河临沂市城区段菹草为研究对象,在菹草暴发生长期间定期采样分析菹草生物量、菹草附着生物膜养分含量及反硝化细菌,同时采用15N同位素添加流动培养结合薄膜进样质谱技术测定菹草附着生物膜的反硝化速率。结果表明:暴发生长期菹草生物量和盖度迅速增加,监测点最大生物量为1817～3334 g/m2;菹草附着生物膜干重、总有机碳、总氮、反硝化功能菌等均明显增加,为附着生物膜反硝化作用提供了丰富的物质和微环境条件;菹草暴发生长期附着生物膜反硝化速率显著升高,监测点最大反硝化作用速率达到424.18～1728.39 μmol/(m2·h),是表层沉积物的17.29～29.09倍;附着生物膜反硝化产氮气(N2)贡献相对较高,对生物膜产N2(反硝化+厌氧氨氧化)的贡献为77%～96%,对河流反硝化产N2的贡献为32%～96%。本研究表明,暴发生长期菹草附着生物膜是沂河的反硝化作用热点,是沂河春季重要的氮去除过程,环境意义重大。建议通过构建沉水植物群落、适度收割、调控水位等措施对菹草进行科学管理调控,以提高城市河流生态系统服务功能。 |
| 关键词: 反硝化 菹草 暴发生长 附着生物膜 生态系统服务 沂河 |
| DOI：10.18307/2023.0109 |
| 分类号: |
| 基金项目:国家自然科学基金项目(41603071)和山东省自然科学基金项目(ZR2021MD045)联合资助。 |
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| Denitrification hotspots existed in the epiphytic biofilms on submerged macrophyte Potamogeton crispus during explosive growing stage in urban river |
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Dong Bin1, Wang Lizhi1, Song Hongli1, Wang Guoxiang2, Liu Yan1
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1.Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection, College of Resources and Environment, Linyi University, Linyi 276000, P. R. China;2.School of Environment, Nanjing Normal University, Nanjing 210023, P. R. China
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| Abstract: |
| Submerged macrophytes are regarded as key components of aquatic ecosystems and also profoundly influence nutrient cycling through various physical, chemical, and metabolic processes. Vegetated shallows may act as hotspots for nitrogen (N) transformation in eutrophic rivers. Explosive growing of submerged macrophyte Potamogeton crispus may support enhanced nitrogen processing, but little is known about the variability of denitrification in epiphytic biofilms of P. crispus and the contributions of denitrification to nitrogen removal in rivers. Yi River of Linyi City is strongly influenced by rubber dam and human activities, and its water is rich in nutrition. P. crispus have become the dominant species in the water area in spring and they have been seen under explosive growth from April to May every year. P. crispus and epiphytic biofilms were sampled at explosive growing stages every 7 days in Yi River, and denitrification rates of epiphytic biofilms were analyzed using a 15N enrichment experiment. The results showed that biomass of P. crispus increased rapidly during explosive growing (from early April to early May) with the maximum biomass of P. crispus at sampling sites up to 1817-3334 g/m2. Dry weight, organic matter, total organic carbon, total nitrogen and denitrifying bacteria of epiphytic biofilms increased significantly, which provided abundant material and microenvironment for denitrification. Denitrification rates (as N2) of epiphytic biofilms significantly increased, the greatest denitrification potential at 6 monitoring sites were 424.18-1728.39 μmol/(m2·h), which was 17.29-29.09 times higher than that of sediments. The contribution to N2 production by denitrification of epiphytic biofilms was high, with 77%-96% to N2 (denitrification + anammox) production of biofilms, and 32%-96% to N2 production by denitrification in river ecosystem. An estimate of epiphytic biofilms N2 production by denitrification in P. crispus beds, based on continuous observations suggests that these epiphytic biofilms are major hotspots for N removal in Yi River during the later spring months. Scientific management and regulation of P. crispus beds through constructing complex submerged plant communities, moderating harvesting, and regulating water levels for urban river ecosystem service restoration efforts have been recommended. |
| Key words: Denitrification Potamogeton crispus explosive growing periphytic biofilm ecosystem service Yi River |
