title: Determination of Trophic State Changes with Diel Dissolved Oxygen: A Case Study in a Shallow Lake.
abstract: Current trophic state indices (TSI) have been reported to have limitations in assessing changes in eutrophication status of shallow waters. This study aimed to use intensive measurements on dissolved oxygen (DO) to improve the determination of tropic state changes. The authors deployed an environment monitoring buoy in a eutrophic shallow lake and recorded water temperature, DO, and chlorophyll-a concentrations at 15-minute intervals for two 1-year periods: from August 2008 to July 2009 and from August 2013 to July 2014. In addition, they recorded water levels over the same periods and collected water samples for nutrient analysis. The authors analyzed the high-time resolution DO records, compared the diel DO trends between the two 1-year periods, and proposed a new TSI using DO. They found that analyzing the change in diel DO ranges can improve commonly used methods for classifying trophic states and assessing the change of eutrophication status of waterbodies.
authors.affiliation: School of Renewable Natural Resources, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Xu
authors.forename: Y Jun
authors.initials: YJ
authors.lastname: Xu
mesh_terms: D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D005068:Eutrophication; D060106:Lakes / Q000032:analysis*; D010100:Oxygen / Q000032:analysis*; D012621:Seasons
chemical_list: D002734:Chlorophyll; D010100:Oxygen; D000077194:Chlorophyll A