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Titel |
Optics and remote sensing of Bahamian carbonate sediment whitings and potential relationship to wind-driven Langmuir circulation |
VerfasserIn |
H. M. Dierssen, R. C. Zimmerman, D. J. Burdige |
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 ; 6, no. 3 ; Nr. 6, no. 3 (2009-03-31), S.487-500 |
Datensatznummer |
250003541
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Publikation (Nr.) |
copernicus.org/bg-6-487-2009.pdf |
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Zusammenfassung |
Regions of milky white seas or "whitings" periodically occur to the west of
Andros Island along the Great Bahama Bank where the bottom sediment consists
of fine-grained aragonite mud. We present measurements of inherent optical
properties within a sediment whiting patch and discuss the potential for
monitoring the frequency, extent, and quantity of suspended matter from ocean
colour satellite imagery. Sea spectral reflectance measured in situ and
remotely from space revealed highly reflective waters elevated across the
visible spectrum (i.e., "whitened") with a peak at 490 nm. Particulate
backscattering was an order of magnitude higher than that measured at other
stations throughout the region. The whiting also had one of the highest
backscattering ratios measured in natural waters (0.05–0.06) consistent with
water dominated by aragonite particles with a high index of refraction.
Regular periodicity of 40 and 212 s evident in the light attenuation
coefficient over the sampling period indicated patches of fluctuating
turbidity on spatial scales that could be produced from regular rows of
Langmuir cells penetrating the 5-m water column. We suggest that previously
described mechanisms for sediment resuspension in whitings, such as tidal
bursting and fish activity, are not fully consistent with these data and
propose that wind-driven Langmuir cells reaching the full-depth of the water
column may represent a plausible mechanism for sediment resuspension and
subsequent whiting formation. Optics and remote sensing provide important
tools for quantifying the linkages between physical and biogeochemical
processes in these dynamic shallow water ecosystems. |
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