Low export flux of particulate organic carbon in the central Arctic Ocean as revealed by234Th:238U disequilibrium

Particulate organic carbon (POC) is one of main component of carbon cycle in the Ocean. In this study an attempt to construct a picture of the distribution and fluxes of POC in the Arctic Ocean adjusting for interchange with the Pacific and Atlantic Oceans has been made. The specificity of this construction is associated with an irregular distribution of POC measurements and complicated structure and hydrodynamics of the waters masses. To overcome these difficulties, Multiple Linear Regression technic (MLR) was performed to test the significant relation between POC, temperature, salinity, as well depth, horizon, latitude and offshore distance. The mapping of POC distribution and its fluxes was carrying out at 38 horizons from 5 to 4150 m (resolution 1°×1°). Data on temperature, salinity, meridional and zonal components of current velocities were obtained from ORA S4 database (Integrated Climate Data Center, http://icdc.cen.uni-hamburg.de/las). The import-export of POC between the Arctic, Atlantic and Pacific Oceans as well as between Arctic Seas was precomputed by summer fluxes. The import of POC in the Arctic Ocean is estimated to be 38±8Tg Cyr-1, and the export is -9.5±4.4Tg Cyr-1.

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Export flux of particulate organic carbon from the central equatorial Pacific determined using a combined drifting trap-234Th approach

Deep Sea Research Part II Topical Studies in Oceanography ◽

10.1016/0967-0645(96)00036-7 ◽

1996 ◽

Vol 43 (4-6) ◽

pp. 1095-1132 ◽

Cited By ~ 167

Author(s):

James W. Murray ◽

Jennifer Young ◽

Jan Newton ◽

John Dunne ◽

Thomas Chapin ◽

...

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

Equatorial Pacific ◽

Export Flux ◽

Central Equatorial Pacific

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Summertime Chlorophyll a and Particulate Organic Carbon Standing Stocks in Surface Waters of the Fram Strait and the Arctic Ocean (1991–2015)

Frontiers in Marine Science ◽

10.3389/fmars.2020.00350 ◽

2020 ◽

Vol 7 ◽

Author(s):

Eva-Maria Nöthig ◽

Simon Ramondenc ◽

Antonie Haas ◽

Laura Hehemann ◽

Andreas Walter ◽

...

Keyword(s):

Organic Carbon ◽

Arctic Ocean ◽

Particulate Organic Carbon ◽

Chlorophyll A ◽

Surface Waters ◽

The Arctic ◽

Fram Strait ◽

The Arctic Ocean ◽

Standing Stocks

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The export flux of particulate organic carbon derived from <sup>210</sup>Po∕<sup>210</sup>Pb disequilibria along the North Atlantic GEOTRACES GA01 transect: GEOVIDE cruise

Biogeosciences ◽

10.5194/bg-16-309-2019 ◽

2019 ◽

Vol 16 (2) ◽

pp. 309-327 ◽

Cited By ~ 3

Author(s):

Yi Tang ◽

Nolwenn Lemaitre ◽

Maxi Castrillejo ◽

Montserrat Roca-Martí ◽

Pere Masqué ◽

...

Keyword(s):

Organic Carbon ◽

Particulate Organic Carbon ◽

North Atlantic ◽

Study Region ◽

Vertical Advection ◽

Export Flux ◽

The North ◽

Iberian Basin ◽

Poc Export ◽

The North Atlantic

Abstract. The disequilibrium between 210Po activity and 210Pb activity in seawater samples was determined along the GEOTRACES GA01 transect in the North Atlantic during the GEOVIDE cruise (May–June 2014). A steady-state model was used to quantify vertical export of particulate 210Po. Vertical advection was incorporated into one version of the model using time-averaged vertical velocity, which had substantial variance. This resulted in large uncertainties for the 210Po export flux in this model, suggesting that those calculations of 210Po export fluxes should be used with great care. Despite the large uncertainties, there is no question that the deficits of 210Po in the Iberian Basin and at the Greenland Shelf have been strongly affected by vertical advection. Using the export flux of 210Po and the particulate organic carbon (POC) to 210Po ratio of total (> 1 µm) particles, we determined the POC export fluxes along the transect. Both the magnitude and efficiency of the estimated POC export flux from the surface ocean varied spatially within our study region. Export fluxes of POC ranged from negligible to 10 mmol C m−2 d−1, with enhanced POC export in the Labrador Sea. The cruise track was characterized by overall low POC export relative to net primary production (export efficiency < 1 %–15 %), but relatively high export efficiencies were seen in the basins where diatoms dominated the phytoplankton community. The particularly low export efficiencies in the Iberian Basin, on the other hand, were explained by the dominance of smaller phytoplankton, such as cyanobacteria or coccolithophores. POC fluxes estimated from the 210Po∕210Pb and 234Th∕238U disequilibria agreed within a factor of 3 along the transect, with higher POC estimates generally derived from 234Th. The differences were attributed to integration timescales and the history of bloom events.

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