Particulate organic carbon export across the Antarctic Circumpolar Current at 10°E Differences between north and south of the Antarctic Polar Front
Puigcorbé, Viena (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Roca Martí, Montserrat (Universitat Autònoma de Barcelona. Institut de Ciència i Tecnologia Ambientals)
Masqué Barri, Pere (Universitat Autònoma de Barcelona. Departament de Física)
Benitez-Nelson, Claudia (University of South Carolina. Department of Earth & Ocean Sciences)
Rutgers v. d. Loeff, Michiel (Helmholtz Centre for Polar and Marine Research. Alfred Wegener Institute)
Laglera, Luis Miguel (Universitat de les Illes Balears. Departament de Química)
Bracher, Astrid (University of Bremen. Institute of Environmental Physics)
Cheah, Wee (Academia Sinica. Research Center for Environmental Changes)
Strass, Volker H. (Helmholtz Centre for Polar and Marine Research. Alfred Wegener Institute)
Hoppema, Mario (Helmholtz Centre for Polar and Marine Research. Alfred Wegener Institute)
Santos-Echeandía, Juan (Instituto de Investigaciones Marinas - CSIC)
Hunt, Brian P.V. (University of British Columbia. Department of Earth, Ocean and Atmospheric Sciences)
Pakhomov, Evgeny A. (University of British Columbia. Department of Earth, Ocean and Atmospheric Sciences)
Klaas, Christine (Helmholtz Centre for Polar and Marine Research. Alfred Wegener Institute)

Date:	2017
Abstract:	The vertical distribution of 234Th was measured along the 10°E meridian between 44°S and 53°S in the Antarctic Circumpolar Current (ACC) during the austral summer of 2012. The overarching goal of this work was to estimate particulate organic carbon (POC) export across three fronts: the Sub-Antarctic Front (SAF), the Antarctic Polar Front (APF) and the Southern Polar Front (SPF). Steady state export fluxes of 234Th in the upper 100 m ranged from 1600 to 2600 dpm m-2 d-1, decreasing with increasing latitude. Using large particle (>53 μm) C/234Th ratios, the 234Th-derived POC fluxes at 100 m ranged from 25 to 41 mmol C m-2 d-1. Observed C/234Th ratios decreased with increasing depth north of the APF while south of the APF, ratios remained similar or even increased with depth. These changes in C/234Th ratios are likely due to differences in the food web. Indeed, satellite images, together with macronutrients and dissolved iron concentrations suggest two different planktonic community structures north and south of the APF. Our results indicate that higher ratios of POC flux at 100 m to primary production occurred in nanophytoplankton dominated surface waters, where primary production rates were lower. Satellite images prior to the expedition suggest that the higher export efficiencies obtained in the northern half of the transect may be the result of the decoupling between production and export (Buesseler 1998). Transfer efficiencies to 400 m, i. e. the fraction of exported POC that reached 400 m, were found to be higher south of the APF, where diatoms were dominant and salps largely abundant. This suggests different remineralization pathways of sinking particles, influencing the transfer efficiency of exported POC to depth.
Grants:	Ministerio de Ciencia e Innovación CTM2011-14027-E Generalitat de Catalunya 2014/SGR-1365 Ministerio de Educación, Cultura y Deporte AP2009-4733 Ministerio de Educación, Cultura y Deporte AP2010-2510 Ministerio de Ciencia e Innovación CGL2010-11846-E
Note:	Unidad de excelencia María de Maeztu MdM-2015-0552
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, i la comunicació pública de l'obra, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original. No es permet la creació d'obres derivades.
Language:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Subject:	Antarctic Circumpolar Current ; Export efficiency ; Particulate organic carbon export ; Plankton community ; Polar Front ; Southern Ocean ; Thorium ; Transfer efficiency
Published in:	Deep-Sea Research Part II: Topical Studies in Oceanography, Vol. 138 (April 2017) , p. 86-101, ISSN 0967-0645

DOI: 10.1016/j.dsr2.2016.05.016

Postprint 37 p, 406.4 KB

The record appears in these collections:
Research literature > UAB research groups literature > Research Centres and Groups (research output) > Experimental sciences > Institut de Ciència i Tecnologia Ambientals (ICTA)
Articles > Research articles
Articles > Published articles