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Hydrogen, carbon monoxide, and methane dynamics in Lake Constance
Author(s) -
Schmidt Ursula,
Conrad Ralf
Publication year - 1993
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1993.38.6.1214
Subject(s) - epilimnion , profundal zone , environmental chemistry , environmental science , methane , hypolimnion , chemistry , eutrophication , littoral zone , oceanography , geology , nutrient , organic chemistry
The vertical distributions of dissolved H 2 , CO, and CH 4 and bacterial production (thymidine incorporation) were measured throughout 1987 in Lake Constance (Bodensee) and again in 1988 at a station in a small bight in the lake. Lake waters were supersaturated with respect to atmospheric H 2 , CO, and CH 4 , especially in the epilimnion; concentrations in the surface water showed a significant ( P < 0.05) positive correlation with either autotrophic picoplankton, primary production, Chl a, pheophytin, or bacterial production. Dissolved H 2 and CO did not exhibit a distinct seasonal pattern, but dissolved CH 4 regularly increased during stratification and decreased in winter. Vertical profiles showed that surface maxima of CH 4 were not due to diffusion from methanogenic profundal sediment. Lateral transects and epilimnetic mass balance indicated that CH 4 may have originated from methanogenic littoral sediments along the shoreline and may also have been produced in oxic epilimnetic water by unknown processes. The water samples contained microbes able to oxidize H 2 , CO, and CH 4 , but threshold concentrations required to sustain oxidation usually were higher than actual in situ concentrations of these gases. We therefore inferred that epilimnetic production of the gases was balanced by evasion to the atmosphere. With the stagnant film model, we determined that the mean residence times of the gases in the epilimniom were on the order of 2–16 d.