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| Titel |
Autonomous, high-resolution observations of particle flux in the oligotrophic ocean |
| VerfasserIn |
M. L. Estapa, K. Buesseler, E. Boss, G. Gerbi |
| 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. 8 ; Nr. 10, no. 8 (2013-08-16), S.5517-5531 |
| Datensatznummer |
250085300
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| Publikation (Nr.) |
 copernicus.org/bg-10-5517-2013.pdf |
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| Zusammenfassung |
| Observational gaps limit our understanding of particle flux attenuation
through the upper mesopelagic because available measurements (sediment traps
and radiochemical tracers) have limited temporal resolution, are
labor-intensive, and require ship support. Here, we conceptually evaluate an
autonomous, optical proxy-based method for high-resolution observations of
particle flux. We present four continuous records of particle flux collected
with autonomous profiling floats in the western Sargasso Sea and the
subtropical North Pacific, as well as one shorter record of depth-resolved
particle flux near the Bermuda Atlantic Time-series Study (BATS) and Oceanic
Flux Program (OFP) sites. These observations illustrate strong variability in
particle flux over very short (~1-day) timescales, but at longer
timescales they reflect patterns of variability previously recorded during
sediment trap time series. While particle flux attenuation at BATS/OFP agreed
with the canonical power-law model when observations were averaged over a
month, flux attenuation was highly variable on timescales of 1–3 days.
Particle fluxes at different depths were decoupled from one another and from
particle concentrations and chlorophyll fluorescence in the
immediately overlying surface water, consistent with horizontal advection of
settling particles. We finally present an approach for calibrating this
optical proxy in units of carbon flux, discuss in detail the related,
inherent physical and optical assumptions, and look forward toward the
requirements for the quantitative application of this method in highly
time-resolved studies of particle export and flux attenuation. |
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