白洋淀水体pH值时空变异特征及影响机制研究
- Characteristics of spatiotemporal variability of water pH in Baiyangdian and its influence mechanism.
- 基金项目：国家重点研发计划(2022YFC3204003)；鄂尔多斯市科技重大专项（ZD20232315）
- 王云霄
- 中国科学院生态环境研究中心环境水质学国家重点实验室
- 单保庆
- 中国科学院生态环境研究中心环境水质学国家重点实验室
- 张文强
- 中国科学院生态环境研究中心环境水质学国家重点实验室
- 胡博洋
- 河北工程大学能源与环境工程学院;河北工程大学能源与环境工程学院
- 摘要：pH值是水体酸碱度的重要指标，全面了解pH值变化的生物地球化学和物理驱动因素对于预测和减轻pH值变化对水生环境的影响至关重要.基于对白洋淀不同季节、不同生境水体pH值开展的昼夜连续监测，系统分析了pH值时空动态特征，探讨了影响pH值的过程和机制.结果表明，pH值呈昼高夜低的规律性波动，在生态系统代谢旺盛的沉水植物生境，春、夏季pH值在日尺度上呈现“宽幅急变”特征，变幅达2.07（范围为7.88~9.95），且表现出白天分层与夜间混合交替的垂向特征，垂直梯度高达1.51（从表层到底层范围为9.87~8.36）；在水生生态系统中，代谢与碳酸盐缓冲的耦合机制驱动pH值呈现复杂动态，强烈的水生生态系统代谢活动是导致pH值高时空变异性的主要原因，碳酸盐平衡体系在pH值变化过程中发挥着重要的缓冲作用，但其缓冲能力有限，并不能完全抵消代谢导致的pH值变化.研究结果完善了水生生态系统中 pH 值变化机制的理论体系，为解决白洋淀pH极端高值和异常波动提供科学支撑.
- Abstract：pH is an essential indicator of the acidity and alkalinity of water bodies. A comprehensive understanding of its biogeochemical and physical drivers is critical for accurately predicting and mitigating its ecological impacts. Based on continuous diurnal pH monitoring across different seasons and habitats in Baiyangdian Lake, this study systematically analyzed the spatial and temporal dynamics of pH and explored the underlying mechanisms driving its variation. The results showed that pH exhibited regular diurnal fluctuations, with pronounced “wide and rapid” daily changes in submerged plant-dominated habitats during spring and summer. In these zones, the pH varied at rates up to 2.07 units per day (ranging from 7.88 to 9.95), and showed a distinctive vertical profile characterized by daytime stratification and nighttime mixing, with a maximum vertical gradient of 1.51 units (ranging from 9.87 at the surface to 8.36 at the bottom). The pH dynamics in aquatic ecosystems are regulated by the coupling of ecosystem metabolic processes and the carbonate buffering system. Strong metabolic activity is the primary driver of high spatiotemporal variability in pH, while the carbonate equilibrium system provides a buffering effect that mitigates, but does not fully counterbalance, these changes. This study refines the theoretical understanding of pH variation mechanisms in freshwater ecosystems and provides a scientific basis for managing extreme pH events and abnormal fluctuations in Baiyangdian Lake.
