State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Science, Nanjing, 210008, China; University of Chinese Academy of Sciences, Beijing, 100039, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Science, Nanjing, 210008, China.
Sci Total Environ. 2023 Dec 15;904:166715. doi: 10.1016/j.scitotenv.2023.166715. Epub 2023 Sep 4.
Lakes on the Qinghai-Tibet Plateau (QTP) have been subject to multiple environmental pressures from rapid climate change and intensified human activity in recent decades. However, their ecological effects on the lake ecosystem remain largely unclear due to the lack of long-term monitoring data. This study presented the environmental and ecological changes of the lake Yamzhog Yumco (Southern QTP) over the past three decades based on multi-proxy analysis (geochemistry and sedaDNA) on a high-time resolution sediment core. The result showed that the lake exhibited a continuous eutrophication process from 2004 CE, which has accelerated since 2014 CE. The nutrient enrichment was mainly attributed to anthropogenic emissions from the catchment. The sedimentary ancient DNA (sedaDNA) metabarcoding data registered a sensitive response of aquatic communities to the additional nutrient supply. Eukaryotic algae and aquatic invertebrate communities exhibited similar temporal dynamics, characterized by the increase in eutrophic taxa and the decrease in oligotrophic taxa. Change points analysis suggested that lake ecosystems underwent a slight ecological shift in 2003 CE and an abrupt shift in 2012 CE driven by nutrient enrichment. Quantitative analysis revealed that nutrients and human activity accounted for 27.9 % and 21.7 % of the temporal variation in aquatic communities, whereas climate change only explained 6.9 % of the total variation. From a paleolimnological view, our study supported that regional human activity could distinctly alter the nutrient level and aquatic community structure of lake ecosystems in the QTP. Considering that anthropogenic disturbance will continuously increase, it is crucial to strengthen the field monitoring of the lakes on the plateau and make effective management measures to avoid irreversible ecological consequences.
青藏高原上的湖泊在过去几十年中受到了快速气候变化和人类活动加剧的多种环境压力。然而，由于缺乏长期监测数据，它们对湖泊生态系统的生态影响在很大程度上仍不清楚。本研究通过对青藏高原南部 Yamzhog Yumco 湖的一个高时间分辨率沉积岩芯进行多指标分析（地球化学和古 DNA），揭示了过去三十年该湖泊的环境和生态变化。结果表明，自 2014 年以来，湖泊一直处于持续富营养化过程中，且这一过程正在加速。营养物质的富集主要归因于集水区的人为排放。沉积古 DNA（sedaDNA）宏条形码数据记录了水生群落对额外营养供应的敏感响应。真核藻类和水生无脊椎动物群落表现出相似的时间动态，表现为富营养类群增加和贫营养类群减少。变化点分析表明，湖泊生态系统在 2003 年和 2012 年经历了轻微的生态转变和突然的转变，这主要是由营养物质的富集驱动的。定量分析表明，营养物质和人类活动分别解释了水生群落时间变化的 27.9%和 21.7%，而气候变化仅解释了总变化的 6.9%。从古湖泊学的角度来看，本研究支持区域人类活动可以明显改变青藏高原湖泊的营养水平和水生群落结构。考虑到人为干扰将持续增加，加强高原湖泊的实地监测并采取有效的管理措施以避免不可逆转的生态后果至关重要。
