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Measurements of eddy correlation oxygen fluxes in shallow freshwaters: Towards routine applications and analysis
Author(s) -
McGinnis Daniel F.,
Berg Peter,
Brand Andreas,
Lorrai Claudia,
Edmonds Theresa J.,
Wüest Alfred
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2007gl032747
Subject(s) - eddy covariance , oxygen , flux (metallurgy) , environmental science , atmospheric sciences , diurnal cycle , advection , daytime , benthic zone , eddy diffusion , turbulence , chemistry , meteorology , oceanography , geology , physics , ecosystem , thermodynamics , ecology , biology , organic chemistry
Benthic fluxes of dissolved oxygen are measured in a shallow reservoir using the eddy correlation technique. Flux variations depict the diurnal production‐consumption cycle, with daytime oxygen release following the solar radiation trend. The average nighttime uptake of −40 ± 11 mmol m −2 d −1 is in excellent agreement with the rate of −35 ± 3 mmol m −2 d −1 derived from sediment oxygen microprofiles. Separating large‐scale advective and turbulent fluctuations is a crucial and uncertain component of the flux computation and the largest source of error. To compensate for the 2.25 s oxygen sensor response time, the oxygen flux calculations are corrected by only ∼5% using a first‐order spectral enhancement. This work demonstrates that only a slightly faster oxygen sensor would be needed to resolve the entire flux spectrum. The 18 hours of data are the first measurements obtained in a freshwater reservoir that capture the diurnal oxygen production‐consumption cycle.