Deng Hongyang, Li Qisheng, Li Mengyuan, Sun Lijie, Li Biao, Wang Yujing, Wu Qinglong L, Zeng Jin
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China; School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing, 210044, China.
Environ Res. 2024 Feb 1;242:117754. doi: 10.1016/j.envres.2023.117754. Epub 2023 Nov 26.
Submerged macrophytes play important roles in nutrient cycling and are widely used in ecological restoration to alleviate eutrophication and improve water quality in lakes. Epiphytic microbial communities on leaves of submerged macrophytes might promote nitrogen cycling, but the mechanisms and quantification of their contributions remain unclear. Here, four types of field zones with different nutrient levels and submerged macrophytes, eutrophic + Vallisneria natans (EV), eutrophic + V. natans + Hydrilla verticillata, mesotrophic + V. natans + H. verticillata, and eutrophic without macrophytes were selected to investigate the microbial communities that involved in nitrification and denitrification. The alpha diversity of bacterial community was higher in the phyllosphere than in the water, and that of H. verticillata was higher compared to V. natans. Bacterial community structures differed significantly between the four zones. The highest relative abundance of dominant bacterioplankton genera involved in nitrification and denitrification was observed in the EV zone. Similarly, the alpha diversity of the epiphytic ammonia-oxidizing archaea and nosZI-type denitrifiers were highest in the EV zone. Consist with the diversity patterns, the potential denitrification rates were higher in the phyllosphere than those in the water. Higher potential denitrification rates in the phyllosphere were also found in H. verticillata than those in V. natans. Anammox was not detected in all samples. Nutrient loads, especially nitrogen concentrations were important factors influencing potential nitrification, denitrification rates, and bacterial communities, especially for the epiphytic nosZI-type taxa. Overall, we observed that the phyllosphere harbors more microbes and promotes higher denitrification rates compared to water, and epiphytic bacterial communities are shaped by nitrogen nutrients and macrophyte species, indicating that epiphytic microorganisms of submerged macrophytes can effectively contribute to the N removal in shallow lakes.
沉水植物在营养物质循环中发挥着重要作用，并且在生态修复中被广泛用于缓解富营养化和改善湖泊水质。沉水植物叶片上的附生微生物群落可能会促进氮循环，但其作用机制和贡献的量化仍不清楚。在此，选择了四种具有不同营养水平和沉水植物的野外区域，即富营养化 + 苦草（EV）、富营养化 + 苦草 + 黑藻、中营养化 + 苦草 + 黑藻以及无沉水植物的富营养化区域，来研究参与硝化和反硝化作用的微生物群落。叶际细菌群落的α多样性高于水体，且黑藻的α多样性高于苦草。四个区域的细菌群落结构存在显著差异。在EV区域观察到参与硝化和反硝化作用的优势浮游细菌属的相对丰度最高。同样，附生氨氧化古菌和nosZI型反硝化菌的α多样性在EV区域也最高。与多样性模式一致，叶际的潜在反硝化速率高于水体。在黑藻的叶际也发现其潜在反硝化速率高于苦草。所有样品中均未检测到厌氧氨氧化。营养负荷，尤其是氮浓度是影响潜在硝化、反硝化速率和细菌群落的重要因素，特别是对于附生的nosZI型类群。总体而言，我们观察到与水体相比，叶际含有更多微生物并促进更高的反硝化速率，并且附生细菌群落受氮养分和沉水植物种类的影响，这表明沉水植物的附生微生物可以有效地促进浅水湖泊中的氮去除。
