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| Titel |
UV/PAR radiation and DOM properties in surface coastal waters of the Canadian shelf of the Beaufort Sea during summer 2009 |
| VerfasserIn |
J. Para, B. Charrière, A. Matsuoka, W. L. Miller, J. F. Rontani, R. Sempéré |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 4 ; Nr. 10, no. 4 (2013-04-26), S.2761-2774 |
| Datensatznummer |
250018219
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| Publikation (Nr.) |
 copernicus.org/bg-10-2761-2013.pdf |
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| Zusammenfassung |
| Surface waters from the Beaufort Sea in the Arctic Ocean were evaluated for
dissolved organic carbon (DOC), and optical characteristics including UV
(ultraviolet) radiation and PAR (photosynthetically active radiation) diffuse
attenuation (Kd), and chromophoric and fluorescent dissolved
organic matter (CDOM and FDOM) as part of the MALINA field campaign (30 July
to 27 August). Spectral absorption coefficients (aCDOM (350 nm)
(m−1)) were significantly correlated to both diffuse attenuation
coefficients (Kd) in the UV-A and UV-B and to DOC concentrations.
This indicates CDOM as the dominant attenuator of both UV and PAR solar
radiation and suggests its use as an optical proxy for DOC concentrations in
this region. While the Mackenzie input is the main driver of CDOM dynamics in
low salinity waters, locally, primary production can create significant
increases in CDOM. Extrapolating CDOM to DOC relationships, we estimate that
∼16% of the DOC in the Mackenzie River does not absorb radiation
at 350 nm. The discharges of DOC and its chromophoric subset (CDOM) by the
Mackenzie River during the MALINA cruise are estimated as ∼0.22 TgC
and 0.18 TgC, respectively. Three dissolved fluorescent components (C1–C3)
were identified by fluorescence excitation/emission matrix spectroscopy
(EEMS) and parallel factor (PARAFAC) analysis. Our results showed an aquatic
dissolved organic matter (DOM) component (C1), probably produced in the
numerous lakes of the watershed, that co-dominated with a terrestrial
humic-like component (C2) in the Mackenzie Delta Sector. This aquatic DOM
could partially explain the high CDOM spectral slopes observed in the
Beaufort Sea. |
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