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| Titel |
Characterization of the bio-optical anomaly and diurnal variability of particulate matter, as seen from scattering and backscattering coefficients, in ultra-oligotrophic eddies of the Mediterranean Sea |
| VerfasserIn |
H. Loisel, V. Vantrepotte, K. Norkvist, X. Mériaux, M. Kheireddine, J. Ras, M. Pujo-Pay, Y. Combet, K. Leblanc, G. Dall'Olmo, R. Mauriac, D. Dessailly, T. Moutin |
| 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 ; 8, no. 11 ; Nr. 8, no. 11 (2011-11-14), S.3295-3317 |
| Datensatznummer |
250006201
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| Publikation (Nr.) |
 copernicus.org/bg-8-3295-2011.pdf |
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| Zusammenfassung |
| The variability of inherent optical properties is investigated in the
ultra-oligotrophic waters of the Mediterranean Sea sampled during the BOUM
experiment performed during early summer 2008. Bio-optical relationships
found for ultra-oligotrophic waters of the three anticyclonic gyres sampled
significantly depart from the mean standard relationships provided for the
global ocean, confirming the peculiar character of these Mediterranean
waters. These optical anomalies are diversely related to the specific
biological and environmental conditions occurring in the studied ecosystem.
Specifically, the surface specific phytoplankton absorption coefficient
exhibits values lower than those expected from the general relationships
mainly in relation with a high contribution of relatively large sized
phytoplankton. Conversely, the particulate backscattering coefficient,
bbp, values are much higher than the mean standard values for a given
chlorophyll-a concentration, TChl-a. This feature can presumably be related to the
relevant influence of highly refractive submicrometer particles of Saharan
origin in the surface layer of the water column. The present measurements
also show that the Mediterranean Sea is greener than TChl-a alone indicates, as
already stressed in previous studies. This color anomaly is partly explained
by the estimated colored dissolved organic matter and submicrometer
particles absorption coefficients, and to a greater extent by the high
bbp/TChl-a values assuming that these particles backscatter light similarly in
the green and blue parts of the visible spectrum. The diel variation of both
the particulate matter attenuation and backscattering coefficients were also
investigated specifically. Despite some differences in the timing and the
magnitude of the daily oscillations found for these optical parameters,
potential for the backscattering coefficient daily oscillation to be used,
similarly to that for the attenuation coefficient, as a proxy for estimating
carbon community production budget has been highlighted for the first time.
This result is particularly relevant for present and future geostationary
spatial ocean color missions. |
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