作者：Leng, P., Zhao, F., Tong, Y. & Kong, X.

Shallow lakes are biogeochemical hotspots that play a disproportionate role in global carbon cycles, yet surface oxygen (O2) dynamics-critical for estimating metabolic activity and CO2 fluxes-remain poorly characterized across spatial and temporal scales. While most studies emphasize temporal and vertical variations, horizontal heterogeneity across lake surfaces is often overlooked. To address this gap, we compiled high-frequency, multisite surface O2 monitoring data throughout 2021 in two large shallow lakes-the temperate Lake Hulun and the subtropical Lake Taihu. By partitioning horizontal spatial and temporal O2 variance, we found that single-site sampling misestimated lake-wide O2 concentrations by up to 29% and metabolic rates by up to 147%. Seasonal changes were the dominant driver of O2 dynamics, introducing even greater errors (34-35%), while daily variability contributed 13-20% uncertainty, highlighting the limitations of infrequent sampling. Environmental controls operated at distinct scales: spatial O2 heterogeneity was shaped by ecosystem respiration and algal gradients; seasonal variations were driven primarily by temperature and metabolic cycles; and daily (diel) fluctuations were governed by the interplay between production and respiration, moderated by carbonate buffering. Horizontal heterogeneity consistently distorted lake-wide metabolic estimates, underscoring the need to integrate spatial O2 data into ecosystem models to reduce errors in lake metabolism estimates. High-resolution spatiotemporal monitoring and targeted seasonal sampling are imperative to constrain uncertainties in lake metabolism and carbon flux estimates under climate change.

浅水湖泊是生物地球化学热点，在全球碳循环中发挥着不成比例的重要作用。然而，对评估代谢活动和二氧化碳通量至关重要的表层溶解氧动态，其时空尺度特征仍缺乏充分认识。多数研究强调时间和垂直方向的变化，湖面水平方向上的异质性却常被忽视。为弥补这一不足，我们整理了2021年全年在两个大型浅水湖泊——温带呼伦湖和亚热带太湖——采集的高频、多站点表层溶解氧监测数据。通过对溶解氧的水平空间与时间方差进行划分，我们发现，单点采样对全湖溶解氧浓度的错误估计最高可达29%，对代谢速率的错误估计最高可达147%。季节变化是溶解氧动态的主导驱动因素，带来甚至更大的误差（34–35%），而日间变异性则贡献了13–20%的不确定性，凸显了低频采样的局限性。环境控制因素在不同尺度上发挥作用：空间上的溶解氧异质性由生态系统呼吸和藻类梯度塑造；季节变化主要由温度和代谢周期驱动；昼夜波动则取决于生产与呼吸的相互作用，并受碳酸盐缓冲作用的调节。水平异质性持续扭曲全湖代谢估算，这凸显了将空间溶解氧数据整合到生态系统模型中，以减少湖泊代谢估算误差的必要性。高分辨率的时空监测和针对性的季节性采样，对于约束气候变化背景下湖泊代谢和碳通量估算的不确定性至关重要。

（来源：Water Research 2026  DOI: 10.1016/j.watres.2026.125391）