| 引用本文: | 王丹阳,韩锦诚,黎睿,汤显强.2022年极端干旱下洞庭湖区水体营养状态变化及改善对策.湖泊科学,2023,35(6):1970-1978. DOI:10.18307/2023.0624 |
| Wang Danyang,Han Jincheng,Li Rui,Tang Xianqiang.Nutritional characteristics in the waterbody of Lake Dongting area nutrient condition and associated improvement measures under the extreme drought in 2022. J. Lake Sci.2023,35(6):1970-1978. DOI:10.18307/2023.0624 |
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| 2022年极端干旱下洞庭湖区水体营养状态变化及改善对策 |
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王丹阳1,2,3, 韩锦诚1,2, 黎睿1,2, 汤显强1,2
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1.长江科学院流域水环境研究所, 武汉 430010;2.流域水资源与生态环境科学湖北省重点实验室, 武汉 430010;3.江西省水利科学院江西省鄱阳湖水资源与环境重点实验室, 南昌 330029
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| 摘要: |
| 2022年夏季长江流域遭受极端干旱,在此背景下,围绕长江荆江河段(松滋-城陵矶),东、西、南洞庭湖,松滋河、虎渡河、藕池河三口水系,湘江、资水、沅江、澧水四水尾闾河段,以及环洞庭湖主要垸区,开展了原位监测和采样工作,测定了湖泊、河道、沟渠、池塘等各类水体中氮、磷、碳等生源要素和叶绿素a浓度,以及浮游植物种类和丰度。结果显示,东、西、南洞庭湖中,总氮、总磷、溶解态有机碳和叶绿素a浓度均值分别为0.57 mg/L、0.45 mg/L、38 mg/L和5.38 μg/L,氮、磷分别以溶解态和颗粒态为主;浮游植物共检出6门37种,以硅藻和绿藻为主,藻类生物量约1.337 mg/L。就综合营养状态指数而言,洞庭湖处于中营养状态,并不显著高于长江和三口四水。极端干旱导致荆江-洞庭湖的水文连通削弱,洞庭湖来自三口的生源要素通量减少,来自四水和湖内自源生产的比重增加;洞庭湖垸区与外部自然河湖的阻隔限制垸内水体自由流动,导致生源要素累积,造成富营养化。2022年极端干旱气象条件下,洞庭湖总磷、叶绿素a、浮游植物数量相比历史阶段数据处于高位,但总氮浓度低于历史水平。恢复水文连通,改善江湖关系,削减内源污染释放,并在垸内通过主动蓄洪建设储备水库,是应对未来极端干旱下湖泊水生态环境问题的可行对策。 |
| 关键词: 洞庭湖 浮游植物 干旱 生源要素 水文连通 垸区 |
| DOI：10.18307/2023.0624 |
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| 基金项目:科技部重点研发项目(2022YFC3204102-02)、江西省水利科学院开放基金项目(2021SKSH 06)和中央级公益性科研院所基本科研业务费项目(CKSF2021443/SH)联合资助。 |
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| Nutritional characteristics in the waterbody of Lake Dongting area nutrient condition and associated improvement measures under the extreme drought in 2022 |
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Wang Danyang1,2,3, Han Jincheng1,2, Li Rui1,2, Tang Xianqiang1,2
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1.Basin Water Environmental Department, Changjiang River Scientific Research Institute, Wuhan 430010, P.R. China;2.Key Laboratory of Basin Water Resource and Eco-Environmental Science in Hubei Province, Wuhan 430010, P.R. China;3.Jiangxi Province Key Laboratory of Water Resources and Environment of Poyang Lake, Jiangxi Institute of Water Science, Nanchang 330029, P.R. China
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| Abstract: |
| There was an extreme drought in the Yangtze River Basin in summer, 2022. In-situ monitoring and sampling were carried out to determine the concentrations of nitrogen, phosphorus, carbon, and chlorophyll-a(Chl.a), as well as phytoplankton species and abundance in various water bodies including river, lake, ditch, and ponder in the Jingjiang River reach (from Songzi to Chenglingji) of the Yangtze River, the east, west, and south Lake Dongting, the three-river system of Songzi, Hudu, and Ouchi, the lower reaches of the Xiang, Zi, Yuan, and Li River, as well as the polders surrounding the Lake Dongting. Results showed that mean concentrations of total nitrogen (TN), total phosphorus (TP), dissolved organic carbon (DOC) and Chl.a in the Lake Dongting were 0.57 mg/L, 0.45 mg/L, 38 mg/L and 5.38 μg/L, respectively. The Lake Dongting was at a moderate level in terms of comprehensive trophic level index (TLI), which was not significantly higher than the Yangtze River, the three outlets, and the four rivers. The main form of nitrogen and phosphorus were dissolved and particulate, respectively. A total of 37 species in 6 phyla of phytoplankton were found, mainly of which were Bacillariophyta and Chlorophyta. The algae biomass was about 1.337 mg/L. The extreme drought weakened hydrological connectivity between Jingjiang and Lake Dongting, resulted in the decrease of biogenic element fluxes from the three-river system, as well as the increase of the proportion from the four rivers and the endogenous production in the lake. The lateral hydrological connectivity between the polders and natural rivers and lakes outside limited the free flow of water inside the polders, causing the accumulation of biogenic elements and thus eutrophication. In 2022, under the extreme drought, TP, Chl.a, and phytoplankton abundance in Lake Dongting were higher than the historical level, but TN concentration was lower than the historical level. It is suggested that river-lake relationship restoration, reducing the release of endogenous pollution, and building reserve reservoirs in polders are feasible measures to cope with the stress of extreme drought on water eco-environment. |
| Key words: Lake Dongting phytoplankton drought biogenic element hydrology connectivity polder |
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