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Title: Carbon export and fate beneath a dynamic upwelled filament off the California coast
Abstract. To understand the vertical variations in carbon fluxes inbiologically productive waters, four autonomous carbon flux explorers(CFEs), ship-lowered CTD-interfaced particle-sensitive transmissometer andscattering sensors, and surface-drogued sediment traps were deployed in afilament of offshore flowing, recently upwelled water, during the June 2017California Current Ecosystem – Long Term Ecological Research process study.The Lagrangian CFEs operating at depths from 100–500 m yielded carbon fluxand its partitioning with size from 30 µm–1 cm at three intensivestudy locations within the filament and in waters outside the filament. Sizeanalysis codes intended to enable long-term CFE operations independent ofships are described. Different particle classes (anchovy pellets, copepodpellets, and > 1000 µm aggregates) dominated the 100–150 mfluxes during successive stages of the filament evolution as it progressedoffshore. Fluxes were very high at all locations in the filament; below150 m, flux was invariant or increased with depth at the two locationscloser to the coast. Martin curve b factors (± denotes 95 %confidence intervals) for total particulate carbon flux were +0.37 ± 0.59, +0.85 ± 0.31, −0.24 ± 0.68, and −0.45 ± 0.70 at thethree successively occupied locations within the plume, and in transitionalwaters. Interestingly, the flux profiles for all particles< 400 µm were a much closer fit to the canonical Martinprofile (b−0.86); however, most (typically > 90 %) ofthe particle flux was carried by > 1000 µm sized aggregateswhich increased with depth. Mechanisms more » to explain the factor of 3 fluxincrease between 150 and 500 m at the mid-plume location are investigated. « less
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3053 to 3086
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National Science Foundation
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