| 2009~2018年太湖湖泛强度变化及其影响因素 |
| 摘要点击 1636 全文点击 817 投稿时间：2020-04-21 修订日期：2020-05-18 |
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| 中文关键词 太湖 湖泛 蓝藻水华 气象条件 环境效应 防控途径 |
| 英文关键词 Lake Taihu black water event(BWF) cyanobacterial bloom meteorological condition environmental effect control countermeasure |
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| 中文摘要 |
| 基于2009~2018年的每年4~10月对太湖湖泛易发区的逐日巡查成果，以及相关太湖气象、水文、水质和水华监测资料的综合分析，揭示了太湖湖泛发生的环境条件及年际差异性特征，分析了影响太湖湖泛强度年际变化的因素及防控途径.结果表明，2009~2018年10 a中太湖共发生大小湖泛事件75次，平均湖泛面积1.35 km2，最大面积9.20 km2，平均持续时间3 d，最长持续16 d；湖泛发生引起了水体有机质、氮和磷等水质指标明显增高；湖泛的发生均在水温20℃以上，发生首日均处在5~9月；年际湖泛强度变化较大，2017年湖泛强度最大，2018年次之，而2014年湖泛强度最小；年际湖泛强度与蓝藻水华强度及5~9月的湖水平均温度显著正相关，而与水体营养盐等指标关系不密切，表明年际气候条件的波动对湖泛情势影响很大；湖泛的形成与河口区蓝藻水华的堆积关系密切：除了5次草源性湖泛外，70次藻源性湖泛均发生在入湖河口附近水域，河口区的底泥污染状况及底泥悬浮状况可能对湖泛的发生具有促进作用.根据形成湖泛的腐烂物质、来源、发生地点和持续时间的不同，可将湖泛分为藻源性湖泛和草源性湖泛这2种类型，藻源性湖泛又可分为港源型、迁移型和原发型这3种.结果表明，控制蓝藻水华强度是降低湖泛风险的根本途径，而避免河口区蓝藻水华过度堆积及厌氧分解的措施，如对蓝藻水华的及时打捞、工程措施形成的局部流场改变、蓝藻水华的离岸打捞工程和滨岸水华堆积区的应急曝气工程，以及河口区的污染底泥疏浚等工程措施，是降低湖泛发生风险的工程措施选项. |
| 英文摘要 |
| Using daily survey and monitoring "black water event" (BWE) results in the sensitive area of Lake Taihu from April to October, 2009-2018, as well as the BWE analyzed data for relative meteorological, hydrological, chemical, and algal bloom conditions, the characteristics and yearly differences of BWEs were summarized. A BWE control strategy was suggested. There were 75 BWE occurrences detected in the past 10 years. The average area of a BWE was 1.35 km2, with a maximum area of 9.20 km2. The BWEs lasted for an average of three days, while the longest lasted 16 days. The BWEs significantly increased organic matter, total nitrogen, total phosphorus, ammonia, and sulfate, among others. All the BWEs occurred at water temperatures over 20℃. All the BWE occurrences started between May and September. The yearly BWE intensity (BWEI) varied significantly among years, with the strongest intensity in 2017 and the second strongest in 2018. The BWEI was significantly positively related to yearly algal bloom intensity (ABI) and average daily water temperature from May to September, while there was no significant relationship with major nutrient indicators. This suggests that climatic variation among years will significantly influence the risk of a BWE in Lake Taihu. The occurrence of a BWE was significantly influenced by a polluted river mouth. Almost all the BWEs occurred near river mouths, except for five macrophyte-related BWEs. This suggests that sediment pollution and its resuspension could be strongly related to the occurrence of a BWE. When considering degradation factors, a BWE could be classified as an algal-related BWE and a macrophyte-related BWE. The algal-related BWE could be further classified into three types:river-related BWE, bloom transport BWE, and local origin BWE. This research suggests that algal bloom control will be the fundamental countermeasure to decrease the risk of a BWE. Bloom abatement treatments, including mechanical bloom cleaning, water current adjustment engineering, coast-away bloom cleaning engineering, mechanical aeration treatment, and sediment dredging near river mouths would be effective methods to abate the risk of a BWE. |
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