Coupling nitrogen removal and watershed management to improve global lake water quality
Xing Yan, Yongqiu Xia, Xu Zhao, Chaopu Ti, Longlong Xia, Scott X. Chang, Xiaoyuan Yan, Xiaoyuan Yan, Xiaoyuan Yan
Abstract
Abstract Lakes play a vital role in nitrogen (N) removal and water quality improvement, yet their efficiency varies due to differing watershed N input and lake characteristics, complicating management efforts. Here we established the N budget for 5768 global lakes using a remote sensing model. We found that watershed N input reduction and lake water quality improvement are nonlinearly related and depends on lake N removal efficiency. A 30% reduction in N loading in watersheds with high N removal efficiencies can improve cumulative water quality by over 70%. Stricter reduction could accelerate achieving water quality goal (≤1 mg N L –1 ), shortening the time by up to 30 years for most lakes. However, heavily polluted lakes with low N removal efficiencies (50 of 534 lakes with >1 mg N L –1 ) may not achieve the UN’s clean water SDG by 2030, even with a 100% N input reduction. Our research highlights the need for targeted N management strategies to improve global lake water quality.