Remote and Local Monitoring of Water Reservoir Eutrophication

Abstract

The work addresses the problem of water body eutrophication and approaches to monitoring this process. It describes key biophysical and chemical markers of water object eutrophication, including the content of chlorophyll-a, suspended solids, and nutrients in water, as well as volatile molecular markers of eutrophication which can be present in air near the water surface. The comparative analysis of experimental, process-based, and theoretical models of this process is performed. Since the volume and quality of experimental data significantly affect the predictive accuracy of eutrophication models, we focus on techniques for accumulating these data, including remote and local sensing of water body parameters. Among the latter, laser gas analysis techniques for detecting volatile markers of eutrophication near water surface are considered. Based on a literature review, a list of the most informative volatile molecular markers of eutrophication emitted from the water surface into the atmosphere has been compiled, i.e., carbon dioxide (CO₂), hydrogen sulfide (H₂S), methane (CH₄), nitric oxide (N₂O), geosmin, and 2-methylisoborneol. The importance of monitoring the phosphorus derivative phosphine (PH₃) is noted, since it is an indicator of the phosphorus cycle and a potential greenhouse gas. The lack of data on its sources and processes of synthesis is emphasized. Based on data on quantum spectral transitions, recommendations are provided for recording PH₃ and other volatile markers of eutrophication near the water–air interface using IR gas absorption spectroscopy.