Technical note: Measurements and data analysis of sediment–water oxygen flux using a new dual-optode eddy covariance instrument
Sediment–water oxygen fluxes are widely used as a proxy for organic carbon production and mineralization at the seafloor. In situ fluxes can be measured non-invasively with the aquatic eddy covariance technique, but a critical requirement is that the sensors of the instrument are able to correctly c...
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Published in | Biogeosciences Vol. 17; no. 17; pp. 4459 - 4476 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Katlenburg-Lindau
Copernicus GmbH
07.09.2020
Copernicus Publications |
Subjects | |
Online Access | Get full text |
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Summary: | Sediment–water oxygen fluxes are widely used as a proxy for
organic carbon production and mineralization at the seafloor. In situ fluxes
can be measured non-invasively with the aquatic eddy covariance technique,
but a critical requirement is that the sensors of the instrument are able to
correctly capture the high-frequency variations in dissolved oxygen
concentration and vertical velocity. Even small changes in sensor
characteristics during deployment as caused, e.g. by biofouling can result in
erroneous flux data. Here we present a dual-optode eddy covariance
instrument (2OEC) with two fast oxygen fibre sensors and document how
erroneous flux interpretations and data loss can effectively be reduced by
this hardware and a new data analysis approach. With deployments over a
carbonate sandy sediment in the Florida Keys and comparison with parallel
benthic advection chamber incubations, we demonstrate the improved data
quality and data reliability facilitated by the instrument and associated
data processing. Short-term changes in flux that are dubious in measurements
with single oxygen sensor instruments can be confirmed or rejected with the
2OEC and in our deployments provided new insights into the temporal dynamics
of benthic oxygen flux in permeable carbonate sands. Under steady
conditions, representative benthic flux data can be generated with the 2OEC
within a couple of hours, making this technique suitable for mapping
sediment–water, intra-water column, or atmosphere–water fluxes. |
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ISSN: | 1726-4189 1726-4170 1726-4189 |
DOI: | 10.5194/bg-17-4459-2020 |