Jiang Wenting, Dai Zhijun, Mei Xuefei, Long Chuqi, Binh Nguyen An, Van Cong Mai, Cheng Jinping
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China.
State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062, China; Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China.
Sci Total Environ. 2024 Mar 20;917:170444. doi: 10.1016/j.scitotenv.2024.170444. Epub 2024 Jan 28.
Lakes, as vital components of the Earth's ecosystem with crucial roles in global biogeochemical cycles, are experiencing pervasive and irreparable worldwide losses due to natural factors and intensive anthropogenic interferences. In this study, we investigated the long-term dynamic patterns of the Tonle Sap Lake, the largest freshwater lake in the Mekong River Basin, using a series of hydrological data and remote sensing images between 2000 and 2020. Our findings revealed a significant decline in the annual average water level of the lake by approximately 2.1 m over 20 years, accompanied by an annual average reduction in surface area of about 1400 km. The Tonle Sap Lake exhibited episodic declines in water level and surface area, characterized by the absence of flooding during the flood season and increasing aridity during the dry season. Furthermore, the shoreline of the lake has significantly advanced towards the lake in the northwestern and southern regions during the dry season, primarily due to sedimentation-induced shallowing of the lake edge depth and decreased water levels. In contrast, lake shorelines in the eastern region remained relatively stable due to the constructed embankments for the protection of the cultivated farmland. While the seasonal fluctuations of the Tonle Sap Lake are regulated by regional precipitation in the Mekong River Basin, the prolonged shrinking of the lake can be mainly ascribed to intensive anthropogenic activities. The interception of dams along the upper Mekong River has resulted in a decrease in the inflow to Tonle Sap Lake, exacerbating its shrinkage. Moreover, there are minor impacts from agricultural land expansion and irrigation on the lake. This study highlights the driving forces behind the evolution of Tonle Sap Lake, providing valuable information for lake managers to develop strategies aimed at conserving and restoring the ecological integrity of the Tonle Sap Lake.
湖泊作为地球生态系统的重要组成部分，在全球生物地球化学循环中发挥着关键作用，但由于自然因素和强烈的人为干扰，正面临着全球范围内普遍且不可修复的损失。在本研究中，我们利用2000年至2020年期间的一系列水文数据和遥感图像，对湄公河流域最大的淡水湖洞里萨湖的长期动态模式进行了调查。我们的研究结果显示，该湖的年平均水位在20年里显著下降了约2.1米，同时湖面面积年平均减少约1400平方千米。洞里萨湖的水位和湖面面积呈现出阶段性下降，其特征是雨季无洪水，旱季干旱加剧。此外，在旱季，该湖北部和南部地区的湖岸线明显向湖中心推进，这主要是由于湖岸边缘深度因泥沙淤积而变浅以及水位下降所致。相比之下，由于修建了保护耕地的堤坝，东部地区的湖岸线相对稳定。虽然洞里萨湖的季节性波动受湄公河流域区域降水的调节，但湖泊的长期萎缩主要可归因于强烈的人为活动。湄公河上游大坝的拦截导致流入洞里萨湖的水量减少，加剧了其萎缩。此外，农业用地扩张和灌溉对湖泊也有轻微影响。本研究突出了洞里萨湖演变背后的驱动因素，为湖泊管理者制定旨在保护和恢复洞里萨湖生态完整性的策略提供了有价值的信息。
