Reply to Qin et al.: Consistency of monitoring data is key to explain the long-term nationwide trend of nutrients in lakes.

We appreciate the response to our recent publication in PNAS (1). Qin et al. (2) state that they found a different total nitrogen/total phosphorus (TN/TP) trend over time by using a different dataset and argue that this difference was mainly caused by a difference in field sample pretreatment and biogeochemical processes.\n\nFirst, the focus of this study is the impact of anthropogenic nutrient discharges on nutrient concentrations in the lakes on a nationwide scale. To our best knowledge, the dataset generated by the National Environmental Monitoring Center (NEMC) is by far the most consistent dataset for assessment of long-term nationwide trends of surface water quality, and this … \n\n[↵][1]1To whom correspondence may be addressed. Email: Yan.Lin{at}niva.no or dongxin{at}tsinghua.edu.cn.\n\n [1]: #xref-corresp-1-1