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Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics

Abstract.

"The sinking of organic particles produced in the upper sunlit layers of the ocean forms an important limb of the oceanic biological pump, which impacts the sequestration of carbon and resupply of nutrients in the mesopelagic ocean. Particles raining out from the upper ocean undergo remineralization by bacteria colonized on their surface and interior, leading to an attenuation in the sinking flux of organic matter with depth. [...]"

Source: Scientific Reports
Authors: Melissa M. Omand et al.
DOI: 10.1038/s41598-020-60424-5

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Air–sea fluxes of greenhouse gases and oxygen in the northern Benguela Current region during upwelling events

Abstract.

"Ground-based atmospheric observations of CO2δ(O2∕N2), N2O, and CH4 were used to make estimates of the air–sea fluxes of these species from the Lüderitz and Walvis Bay upwelling cells in the northern Benguela region, during upwelling events. Average flux densities (±1σ) were 0.65±0.4 µmol m−2 s−1 for CO2, −5.1±2.5 µmol m−2 s−1 for O2 (as APO), 0.61±0.5 nmol m−2 s−1 for N2O, and 4.8±6.3 nmol m−2 s−1 for CH4. A comparison of our top-down (i.e., inferred from atmospheric anomalies) flux estimates with shipboard-based measurements showed that the two approaches agreed within ±55 % on average, though the degree of agreement varied by species and was best for CO2. [...]"

Source: Biogeosciences
Authors: Eric J. Morgan et al.
DOI: 10.5194/bg-16-4065-2019

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Particulate matter flux interception in oceanic mesoscale eddies by the polychaete Poeobius sp.

Abstract.

"Gelatinous zooplankton hold key functions in the ocean and have been shown to significantly influence the transport of organic carbon to the deep sea. We discovered a gelatinous, flux‐feeding polychaete of the genus Poeobius in very high abundances in a mesoscale eddy in the tropical Atlantic Ocean, where it co‐occurred with extremely low particle concentrations. Subsequent analysis of an extensive in situ imaging dataset revealed that Poeobius sp. occurred sporadically between 5°S–20°N and 16°W–46°W in the upper 1000 m. [...]"

Source: Limnology and Oceanography
Authors: Svenja Christiansen et al.
DOI: 10.1002/lno.10926

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Particle export fluxes to the oxygen minimum zone of the eastern tropical North Atlantic

Abstract.  

"In the ocean, sinking of particulate organic matter (POM) drives carbon export from the euphotic zone and supplies nutrition to mesopelagic communities, the feeding and degradation activities of which in turn lead to export flux attenuation. Oxygen (O2) minimum zones (OMZs) with suboxic water layers (< 5 µmol O2 kg−1) show a lower carbon flux attenuation compared to well-oxygenated waters (> 100 µmol O2 kg−1), supposedly due to reduced heterotrophic activity. [...]"

Source: Biogeosciences 14
Authors: Anja Engel et al.
DOI: 10.5194/bg-14-1825-2017

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