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Using noble gases to analyze the efficiency of artificial aeration in Lake Hallwil, Switzerland
Author(s) -
Holzner C. P.,
Tomonaga Y.,
Stöckli A.,
Denecke N.,
Kipfer R.
Publication year - 2012
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2012wr012030
Subject(s) - aeration , noble gas , anoxic waters , supersaturation , eutrophication , environmental science , stratification (seeds) , oxygen , water body , environmental chemistry , environmental engineering , hydrology (agriculture) , chemistry , geology , nutrient , geotechnical engineering , seed dormancy , botany , germination , organic chemistry , dormancy , biology
Eutrophic Lake Hallwil (Switzerland) is equipped with an artificial aeration system to prevent anoxic conditions developing in the deep water during stratification in summer. The aeration system consists of diffusers releasing oxygen‐rich gas containing noble gases into the deep water at the bottom of the lake. The deep water is strongly supersaturated with He, Ne, and Ar, while Kr and Xe are present at concentrations corresponding to their respective atmospheric equilibria. The observed noble gas excesses are related to the operation of the aeration system and to the composition of the injected aeration gas. We show how noble gas data were used successfully to estimate the fraction of the injected aeration gas that effectively remains dissolved in the water body. In particular, as the physical properties of Ar (e.g., atomic mass, solubility, diffusion coefficient) are similar to those of oxygen, the measured noble gas concentrations allow the efficiency of the aeration system to be quantified.