| 摘要: |
| 湖泊是温室气体甲烷(CH4)的重要释放源之一,削减湖泊CH4释放对缓解全球气候变化意义重大。沉水植物恢复作为控制湖泊富营养化的重要手段,可能同时具备削减CH4释放的效果。为验证上述假设,本研究选取江苏省南京市典型城市湖泊玄武湖作为研究对象,通过顶空-平衡法开展了为期1年的野外观测研究,并结合室内培养试验,比较了玄武湖沉水植物恢复区与未恢复区CH4释放、产生和氧化的差异以及沉水植物恢复在其中的可能作用。研究结果显示：玄武湖未恢复区水-气界面CH4的扩散通量的变化范围为23.52-6076.1 μmol/m2/d,年平均值为1244.0 ± 1317.6 μmol/m2/d。未恢复区的CH4释放主要受温度、多种营养盐(总磷、总氮、亚硝态氮、氨氮)、叶绿素a浓度等影响；恢复区的CH4扩散通量显著低于未恢复区(p<0.001),其年平均值仅有未恢复区的23.8%,该区域的CH4释放主要受温度、总磷等影响。沉水植物恢复可能通过以下两种途径削减了CH4释放：(1)沉水植物的恢复显著降低了各类营养盐与叶绿素a浓度(总磷、总氮、叶绿素a分别下降了80.2%、73.6%、72.2%),进而削减了CH4的排放；(2)沉水植物的恢复显著地降低了沉积物不同温度下的产甲烷潜势与其温度敏感性,同时还提高了甲烷氧化潜势,使得净甲烷释放减少。本研究可为湖泊修复与碳汇能力提升的协同提供重要参考。 |
| 关键词: 甲烷、沉水植物、生态修复、产甲烷潜势、甲烷氧化潜势 |
| DOI： |
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| 基金项目:国家自然科学基金项目(U2040201,42293264,32201334), 江苏省碳达峰碳中和科技技术创新专项(BK20220015) |
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| Effects of aquatic plant restoration on methane release in Lake Xuanwu, a typical urban lake |
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Fan shiming1, Gu Yu, Chen He, Wang Hongwei, Xing Peng, Li Biao2, Wu Qinglong
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1.Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences;2.State Key Laboratory of Lakes and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences
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| Abstract: |
| Lakes are one of the important sources of methane (CH4) emission, a greenhouse gas, and reducing CH4 release in lakes is critical to mitigate global climate change. Submerged plant restoration, as an important means to control lake eutrophication, may also contribute to reduce CH4 release. To verify this hypothesis above, Lake XuanWu, a typical urban lake in Nanjing, Jiangsu Province, was selected as the research object in this study. A 1-year in-situ investigation, combined with the incubation test, was conducted to compare the differences in CH4 release, production and oxidation between the submerged plant restored and unrestored areas in Lake Xuanwu and the possible role of submerged plants in it. The results show that the diffusion flux of CH4 at the water-air interface in the unrestored area of Lake Xuanwu ranges from 23.52-6076.1 μmol/m2/d, with the annual mean of 1244.0 ± 1317.6 μmol/m2/d. The CH4 release in the unrestored area was mainly affected by temperature, various nutrients (total phosphorus, total nitrogen, nitrite, ammonia nitrogen) and chlorophyll a concentration. The CH4 diffusion flux in the restored area was significantly lower than that in the unrestored area (p<0.001), and its average annual value was only 23.8% in the unrestored area. The CH4 release in this area was mainly affected by temperature and total phosphorus. Submerged plant may mitigateCH4 emissions through two pathways: (1) Submerged plant restoration significantly reduced the concentration of various nutrients and chlorophyll a (total phosphorus, total nitrogen and chlorophyll a decreased by 80.2%, 73.6% and 72.2%, respectively), thus reducing the emission of CH4; (2) Submerged plant restoration significantly reduced the methanogenesis potential in sediments at different temperatures and temperature sensitivity (Q10) , and also increased the methane oxidation potential, resulting in less CH4 release.This study provides valuable insights for the synergistic enhancement of lake restoration and carbon sequestration capacity. |
| Key words: methane, submerged plant, ecological restoration, methanogenesis potential, methane oxidation potential |
