Brezonik, Patrick LHozalski, Raymond M.Finlay, Jacques C2019-01-152019-01-152019-01-15https://hdl.handle.net/11299/201562The data are in an Excel spreadsheet with rows representing data for a given lake collected on a specific date. Columns provide lake name or unique lake identifier, sampling date, aquatic ecoregion for the lake, results for CDOM (a440), chlorophyll, Secchi depth, and total suspended solids concentrations, and logarithms of the values for the four water quality variables.This file contains approximately 1460 records on four water quality variables measured on near-surface water samples of lakes in Minnesota (primarily) and also in Wisconsin and Michigan collected by our research group from 2014 to 2017 and similar data collected by the Minnesota Pollution Control Agency in its annual lake water quality assessment program from 2015 to 2017. The variables are Secchi depth (SD), colored dissolved organic matter (CDOM) measured as the Napierian light absorption coefficient at 440 nm, chlorophyll-a, and total suspended solids concentrations. The database was used for a published paper to analyze the effects of CDOM on SD and show that high CDOM levels limit light penetration and thus SD in colored lakes.CC0 1.0 Universalhttp://creativecommons.org/publicdomain/zero/1.0/lakes, water clarity, Secchi depth, CDOM, colored dissolved organic matter, suspended solids, chlorophyll, trophic state, ecoregionsDatasethttps://doi.org/10.13020/01WT-JG66