Carbon exchange between a shelf sea and the ocean: The Hebrides Shelf, west of Scotland
Painter, S.C.; Hartman, S.E.; Kivimäe, C.; Salt, L.A.; Clargo, N.M.; Bozec, Y.; Daniels, C.J.; Jones, S.C.; Hemsley, V.S.; Munns, L.R.; Allen, S.R. (2016). Carbon exchange between a shelf sea and the ocean: The Hebrides Shelf, west of Scotland. Journal of Geophysical Research-Oceans 121: 4522–4544. dx.doi.org/10.1002/2015JC011599
In: Journal of Geophysical Research-Oceans. AMER GEOPHYSICAL UNION: Washington. ISSN 2169-9275; e-ISSN 2169-9291, more
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| Authors | | Top |
- Painter, S.C.
- Hartman, S.E.
- Kivimäe, C.
- Salt, L.A.
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- Clargo, N.M., more
- Bozec, Y.
- Daniels, C.J.
- Jones, S.C.
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- Hemsley, V.S.
- Munns, L.R.
- Allen, S.R.
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| Abstract |
Global mass balance calculations indicate the majority of particulate organic carbon (POC)exported from shelf seas is transferred via downslope exchange processes. Here we demonstrate thedownslope flux of POC from the Hebrides Shelf is approximately 3- to 5-fold larger per unit length/areathan the global mean. To reach this conclusion, we quantified the offshore transport of particulate anddissolved carbon fractions via the ‘‘Ekman Drain,’’ a strong downwelling feature of the NW European Shelfcirculation, and subsequently compared these fluxes to simultaneous regional air-sea CO2fluxes andonshore wind-driven Ekman fluxes to constrain the carbon dynamics of this shelf. Along the shelf break, weestimate a mean offshelf total carbon (dissolved 1 particulate) flux of 4.2 tonnes C m21d21compared to anonshelf flux of 4.5 tonnes C m21d21. Organic carbon represented 3.3% of the onshelf carbon flux but 6.4%of the offshelf flux indicating net organic carbon export. Dissolved organic carbon represented 95% andPOC 5% of the exported organic carbon pool. When scaled along the shelf break the total offshelf POC flux(0.007 Tg C d21) was found to be 3 times larger than the regional air-sea CO2ingassing flux (0.0021 Tg Cd21), an order of magnitude larger than the particulate inorganic carbon flux (0.0003 Tg C d21) but farsmaller than the DIC (2.03 Tg C d21) or DOC (0.13 Tg C d21) fluxes. Significant spatial heterogeneity in theEkman drain transport confirms that offshelf carbon fluxes via this mechanism are also spatially heterogeneous |
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