Data compilation of fluxes of sedimenting material from sediment traps in the Atlantic Ocean

The literature on the relative contributions of pelagic calcifying taxa to the global ocean export of CaCO3 is divided. Studies based on deep sediment trap data tend to argue that either foraminifers or coccolithophores, both calcite producers, dominate export. However, the compilations of biomass observations for pteropods, coccolithophores, and foraminifers instead show that pteropods dominate the global ocean calcifier biomass and therefore likely also carbonate export. Here we present a new global ocean biogeochemical model that explicitly represents these three groups of pelagic calcifiers. We synthesize databases of the physiology of the three groups to parameterize the model and then tune the unconstrained parameters to reproduce the observations of calcifier biomass and CaCO3 export. The model can reproduce both these observational databases; however, substantial dissolution of aragonite above the aragonite saturation horizon is required to do so. We estimate a contribution of pteropods to shallow (100 m) export of CaCO3 of at least 33% and to pelagic calcification of up to 89%. The high production‐high dissolution configuration that shows closest agreement with all the observations has a CaCO3 production of 4.7 Pg C/year but CaCO3 export at 100 m of only 0.6 Pg C/year.

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“…Model results have been sampled where there are observations. (black) Observations (Torres Valdés et al, ). (red) Standard model run.…”

Section: Resultsmentioning

confidence: 95%

“…Depth‐averaged sinking flux of CaCO 3 (mg·m −2 ·day −1 ). (a) Observations (Torres Valdés et al, ). (b) Standard model run.…”

Section: Resultsmentioning

confidence: 99%

Large Contribution of Pteropods to Shallow CaCO₃ Export

Buitenhuis

Quéré

Bednaršek

et al. 2019

Global Biogeochemical Cycles

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“…Most of the POM being exported below the surface mixed layer (< 200 m in general) is solubilized and remineralized within the mesopelagic layer, i.e., between depths of 200 and 1000 m (Bishop et al, 1978;Suess, 1980). The shallower the carbon remineralization depth, the more likely CO 2 is to exchange with the atmosphere and hence drive a shorter carbon storage time in the ocean (Volk and Hoffert, 1985;Kwon et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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

Engel¹,

Wagner²,

Moigne³

et al. 2017

Biogeosciences

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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 (O 2 ) minimum zones (OMZs) with suboxic water layers (< 5 µmol O 2 kg −1 ) show a lower carbon flux attenuation compared to welloxygenated waters (> 100 µmol O 2 kg −1 ), supposedly due to reduced heterotrophic activity. This study focuses on sinking particle fluxes through hypoxic mesopelagic waters (< 60 µmol O 2 kg −1 ); these represent ∼ 100 times more ocean volume globally compared to suboxic waters, but they have less been studied. Particle export fluxes and attenuation coefficients were determined in the eastern tropical North Atlantic (ETNA) using two surface-tethered drifting sediment trap arrays with seven trapping depths located between 100 and 600 m. Data on particulate matter fluxes were fitted to the normalized power function F z = F 100 (z/100) −b , with F 100 being the flux at a depth (z) of 100 m and b being the attenuation coefficient. Higher b values suggest stronger flux attenuation and are influenced by factors such as faster degradation at higher temperatures. In this study, b values of organic carbon fluxes varied between 0.74 and 0.80 and were in the intermediate range of previous reports, but lower than expected from seawater temperatures within the upper 500 m. During this study, highest b values were determined for fluxes of particulate hydrolyzable amino acids (PHAA), followed by particulate organic phosphorus (POP), nitrogen (PN), carbon (POC), chlorophyll a (Chl a) and transparent exopolymer particles (TEP), pointing to a sequential degradation of organic matter components during sinking. Our study suggests that in addition to O 2 concentration, organic matter composition co-determines transfer efficiency through the mesopelagic. The magnitude of future carbon export fluxes may therefore also depend on how organic matter quality in the surface ocean changes under influence of warming, acidification and enhanced stratification.

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“…234 Th-based measurements have associated biases accounting for local advection, quantifying particulate adsorption and with variability in the ratio of POC : 234 Th. See the discussions of Buesseler (1991), Buesseler et al (2000), Lee et al (1992), Murray et al (1996), Quay (1997), and van der Loeff et al (2006), for in-depth analyses of these issues. A significant number of studies occurred prior to the launch of SeaWiFS in September 1997 (see Honjo et al, 2008, and references therein).…”

Section: Poc Flux Datamentioning

confidence: 99%

Global ocean particulate organic carbon flux merged with satellite parameters

Mouw

Barnett

McKinley

et al. 2016

Earth Syst. Sci. Data

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Abstract. Particulate organic carbon (POC) flux estimated from POC concentration observations from sediment traps and 234 Th are compiled across the global ocean. The compilation includes six time series locations: CARI-ACO, K2, OSP, BATS, OFP, and HOT. Efficiency of the biological pump of carbon to the deep ocean depends largely on biologically mediated export of carbon from the surface ocean and its remineralization with depth; thus biologically related parameters able to be estimated from satellite observations were merged at the POC observation sites. Satellite parameters include net primary production, percent microplankton, sea surface temperature, photosynthetically active radiation, diffuse attenuation coefficient at 490 nm, euphotic zone depth, and climatological mixed layer depth. Of the observations across the globe, 85 % are concentrated in the Northern Hemisphere with 44 % of the data record overlapping the satellite record. Time series sites accounted for 36 % of the data, while 71 % of the data are measured at ≥ 500 m with the most common deployment depths between 1000 and 1500 m. This data set is valuable for investigations of CO 2 drawdown, carbon export, remineralization, and sequestration. The compiled data can be freely accessed at

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Data compilation of fluxes of sedimenting material from sediment traps in the Atlantic Ocean

Cited by 23 publications

References 53 publications

Large Contribution of Pteropods to Shallow CaCO₃ Export

Large Contribution of Pteropods to Shallow CaCO₃ Export

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

Global ocean particulate organic carbon flux merged with satellite parameters

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Data compilation of fluxes of sedimenting material from sediment traps in the Atlantic Ocean

Cited by 23 publications

References 53 publications

Large Contribution of Pteropods to Shallow CaCO3 Export

Large Contribution of Pteropods to Shallow CaCO3 Export

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

Global ocean particulate organic carbon flux merged with satellite parameters

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Product

Resources

About

Large Contribution of Pteropods to Shallow CaCO₃ Export

Large Contribution of Pteropods to Shallow CaCO₃ Export