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| Titel |
Physical and biogeochemical controls on light attenuation in a eutrophic, back-barrier estuary |
| VerfasserIn |
N. K. Ganju, J. L. Miselis, A. L. Aretxabaleta |
| 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 ; 11, no. 24 ; Nr. 11, no. 24 (2014-12-17), S.7193-7205 |
| Datensatznummer |
250117743
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| Publikation (Nr.) |
 copernicus.org/bg-11-7193-2014.pdf |
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| Zusammenfassung |
| Light attenuation is a critical parameter governing the ecological function
of shallow estuaries. In these systems primary production is often dominated
by benthic macroalgae and seagrass; thus light penetration to the bed is of
primary importance. We quantified light attenuation in three seagrass
meadows in Barnegat Bay, New Jersey, a shallow eutrophic back-barrier
estuary; two of the sites were located within designated Ecologically
Sensitive Areas (ESAs). We sequentially deployed instrumentation measuring
photosynthetically active radiation, chlorophyll a (chl a) fluorescence,
dissolved organic matter fluorescence (fDOM; a proxy for colored dissolved organic matter
(CDOM)
absorbance), turbidity, pressure, and water velocity at 10 min intervals
over 3-week periods at each site. At the southernmost site, where
sediment availability was highest, light attenuation was highest and
dominated by turbidity and to a lesser extent chl a and CDOM. At the central
site, chl a dominated followed by turbidity and CDOM, and at the
northernmost site turbidity and CDOM contributed equally to light
attenuation. At a given site, the temporal variability of light attenuation exceeded the difference in median light attenuation between the three sites.
Vessel wakes, anecdotally implicated in increasing sediment resuspension,
did not contribute to local resuspension within the seagrass beds, though
frequent vessel wakes were observed in the channels. With regards to light
attenuation and water clarity, physical and biogeochemical variables appear
to outweigh any regulation of boat traffic within the ESAs. |
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