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Effects on the benthic diffusive boundary layer imposed by microelectrodes
Author(s) -
Nøhr Glud Ronnie,
Gundersen Jens Kristian,
Revsbech Niels Peter,
Jørgensen Bo Barker
Publication year - 1994
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.1994.39.2.0462
Subject(s) - microelectrode , benthic zone , sediment , layer (electronics) , boundary layer , concentration gradient , diffusion , flux (metallurgy) , materials science , geology , mineralogy , oceanography , chemistry , soil science , electrode , nanotechnology , geomorphology , physics , mechanics , metallurgy , thermodynamics
Oxygen microgradients and fluxes were studied in a 0.3–0.6‐mm‐thick diffusive boundary layer (DBL) of aquatic sediments by the use of O 2 microelectrodes with sensing tips of 5 µ m. One microelectrode was introduced vertically from above while another was introduced along the same vertical axis from below, thus penetrating up through the sediment. Microelectrodes introduced from below did not alter the DBL, but those introduced from above reduced its thickness by 25–45%. The effect was detected even when the microsensor tip was situated >1 mm above the sediment surface. The reduction of the DBL resulted in steepening the O 2 gradient. In typical coastal sediments, the microelectrode thereby increased the diffusive O 2 flux by 8%; in a highly sulfidic sediment the increase was 59%.