A framework to develop joint nutrient criteria for lake eutrophication management in eutrophic lakes

Nutrient criteria provide the numeric basis for lake eutrophication management. However, there are two obstacles that can hinder effective application of nutrient criteria, including 1) although total phosphorus (TP) and nitrogen (TN) might co-limit phytoplankton biomass in eutrophic lakes, their often developed independently; 2) linkage between percentile-based compliance assessment method chlorophyll a (CHL; as measure biomass) has not been well established. To resolve these obstacles, we propose novel analytical framework development, by which joint using quantile regression (QR). We demonstrated steps necessary to utilize this approach TP, TN, CHL data from Lake Dianchi, hypereutrophic located southwestern China. First, built candidate QR models quantify nutrient-CHL relationship at six quantiles. Next, conducted sequential Wald test select “best” model each quantile. Finally, visualized surface contour map. The map effectively illustrated showing TP TN criterion. In addition, based on QR, it was easy deduce met requirement assessment. further found could help selection an efficient load reduction strategy watershed. proposed be generalized other systems may facilitate site-specific