North Atlantic Western Boundary Currents Are Intense Dissolved Organic Carbon Streams

• Published in: Frontiers in Marine Science
• Main Authors: Fontela, Marcos, Pérez, Fiz F., Mercier, Herlé, Lherminier, Pascale
• Other Authors: Ministerio de Economía y Competitividad (España), European Commission
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media 2020
• Subjects: Dissolved organic carbon; North Atlantic; Carbon budgets; Carbon dioxide; Biogeochemistry; Atlantic Meridional Overturning Circulation; Greenland; Mid-Atlantic Ridge; Reykjanes; East Greenland; east greenland current; north atlantic current
• Online Access: http://hdl.handle.net/10261/233556; https://doi.org/10.3389/fmars.2020.593757; https://doi.org/10.13039/501100003329; https://doi.org/10.13039/501100000780

10 pages, 5 figures.-- This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) In the North Atlantic, there are two main western boundary currents related to the Atlantic Meridional Overturning Circulation (AMOC): the Gulf Stream flowing northward and the Deep Western Boundary Current (DWBC) flowing southward. Here we analyze data from the OVIDE section (GO-SHIP A25 Portugal-Greenland 40–60°N) that crosses the DWBC and the northward extension of the Gulf Stream, the North Atlantic Current. We show that North Atlantic western boundary currents play a key role in the transport of dissolved organic matter, specifically dissolved organic carbon (DOC). Revisited transports and budgets of DOC with new available data identify the eastern Subpolar North Atlantic (eSPNA) as an important source of locally produced organic matter for the North Atlantic and a key region in the supply of bioavailable DOC to the deep ocean. The East Greenland Current, and its upstream source the East Reykjanes Ridge Current on the eastern flank of the mid-Atlantic ridge, are export pathways of bioavailable DOC toward subtropical latitudes. The fast overturning and subsequent remineralization of DOC produced in the autotrophic eSPNA explains up to 38% of the total oxygen consumption in the deep North Atlantic between the OVIDE section and 24°N. Carbon budgets that do not take into account this organic remineralization process overestimates the natural uptake of carbon dioxide (CO2) from the atmosphere by one third. The inclusion of DOC transports in regional carbon budgets reconciles the estimates of CO2 uptake in the North Atlantic between model and observations For this work MF was funded by the Spanish Ministry of Economy and Competitiveness (BES-2014-070449) supported by the Spanish Government and co-funded by the Fondo Europeo de Desarrollo Regional 2007–2012 (FEDER) and by Portuguese national funds from FCT – Foundation for Science and Technology through project ...