Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea
In recent decades, the central North Sea has been experiencing a general trend of decreasing dissolved oxygen (O<sub>2</sub>) levels during summer. To understand potential causes driving lower O<sub>2</sub>, we investigated a 3-day period of summertime turbulence and O<sub...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-03-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/1609/2016/bg-13-1609-2016.pdf |
| _version_ | 1819145429295562752 |
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| author | L. Rovelli M. Dengler M. Schmidt S. Sommer P. Linke D. F. McGinnis |
| author_facet | L. Rovelli M. Dengler M. Schmidt S. Sommer P. Linke D. F. McGinnis |
| author_sort | L. Rovelli |
| collection | DOAJ |
| description | In recent decades, the central North Sea has been experiencing a general
trend of decreasing dissolved oxygen (O<sub>2</sub>) levels during summer. To
understand potential causes driving lower O<sub>2</sub>, we investigated a
3-day period of summertime turbulence and O<sub>2</sub> dynamics in the
thermocline and bottom boundary layer (BBL). The study focuses on coupling
biogeochemical with physical transport processes to identify key drivers of
the O<sub>2</sub> and organic carbon turnover within the BBL. Combining our flux
observations with an analytical process-oriented approach, we resolve
drivers that ultimately contribute to determining the BBL O<sub>2</sub> levels. We
report substantial turbulent O<sub>2</sub> fluxes from the thermocline into the
otherwise isolated bottom water attributed to the presence of a baroclinic
near-inertial wave. This contribution to the local bottom water O<sub>2</sub> and
carbon budgets has been largely overlooked and is shown to play a role in
promoting high carbon turnover in the bottom water while simultaneously
maintaining high O<sub>2</sub> concentrations. This process may become suppressed
with warming climate and stronger stratification, conditions which could
promote migrating algal species that potentially shift the O<sub>2</sub>
production zone higher up within the thermocline. |
| first_indexed | 2024-12-22T12:57:53Z |
| format | Article |
| id | doaj.art-ba2d7e35307c4db2ab35c0d4e9d514c2 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-22T12:57:53Z |
| publishDate | 2016-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-ba2d7e35307c4db2ab35c0d4e9d514c22022-12-21T18:25:03ZengCopernicus PublicationsBiogeosciences1726-41701726-41892016-03-011351609162010.5194/bg-13-1609-2016Thermocline mixing and vertical oxygen fluxes in the stratified central North SeaL. Rovelli0M. Dengler1M. Schmidt2S. Sommer3P. Linke4D. F. McGinnis5GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, GermanyGEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, GermanyIn recent decades, the central North Sea has been experiencing a general trend of decreasing dissolved oxygen (O<sub>2</sub>) levels during summer. To understand potential causes driving lower O<sub>2</sub>, we investigated a 3-day period of summertime turbulence and O<sub>2</sub> dynamics in the thermocline and bottom boundary layer (BBL). The study focuses on coupling biogeochemical with physical transport processes to identify key drivers of the O<sub>2</sub> and organic carbon turnover within the BBL. Combining our flux observations with an analytical process-oriented approach, we resolve drivers that ultimately contribute to determining the BBL O<sub>2</sub> levels. We report substantial turbulent O<sub>2</sub> fluxes from the thermocline into the otherwise isolated bottom water attributed to the presence of a baroclinic near-inertial wave. This contribution to the local bottom water O<sub>2</sub> and carbon budgets has been largely overlooked and is shown to play a role in promoting high carbon turnover in the bottom water while simultaneously maintaining high O<sub>2</sub> concentrations. This process may become suppressed with warming climate and stronger stratification, conditions which could promote migrating algal species that potentially shift the O<sub>2</sub> production zone higher up within the thermocline.http://www.biogeosciences.net/13/1609/2016/bg-13-1609-2016.pdf |
| spellingShingle | L. Rovelli M. Dengler M. Schmidt S. Sommer P. Linke D. F. McGinnis Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea Biogeosciences |
| title | Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea |
| title_full | Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea |
| title_fullStr | Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea |
| title_full_unstemmed | Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea |
| title_short | Thermocline mixing and vertical oxygen fluxes in the stratified central North Sea |
| title_sort | thermocline mixing and vertical oxygen fluxes in the stratified central north sea |
| url | http://www.biogeosciences.net/13/1609/2016/bg-13-1609-2016.pdf |
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