Net Additions of Recalcitrant Dissolved Organic Carbon in the Deep Atlantic Ocean

• Published in: Global Biogeochemical Cycles
• Main Authors: Romera-Castillo, Cristina, Álvarez, Marta, Pelegrí, Josep Lluís, Hansell, Dennis A., Álvarez-Salgado, Xosé Antón
• Other Authors: Ministerio de Economía y Competitividad (España)
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Geophysical Union 2019
• Subjects: Cierva; North Atlantic
• Online Access: http://hdl.handle.net/10261/193458; https://doi.org/10.1029/2018GB006162; https://doi.org/10.13039/501100003329

12 pages, 5 figures, 2 tables Most dissolved organic carbon (DOC) sequestered in the deep ocean has residence times of decades to thousands of years, with clear implications for climate regulation, though some net removal is typically observed with increasing water mass age. Here, a high‐quality‐high‐resolution data set has allowed us to identify net additions of recalcitrant DOC in specific water masses of the deep South Atlantic. Overall, the South Atlantic is a net source of recalcitrant DOC, adding 0.027 ± 0.019 Pg C/year, while the North Atlantic is a net sink that removes 0.298 ± 0.141 Pg C/year. We find that the balance of addition/removal of recalcitrant DOC depends not only on the origin but also on the temperature, age, and depth of the water masses that circulate and mix in the Atlantic Ocean. Future changes in the water mass composition and circulation patterns due to climate change would eventually affect that balance, altering the carbon cycle C. R.‐C. was supported by a Juan de la Cierva‐ Incorporación Postdoctoral Fellowship (IJCI‐2015‐23357) from the Spanish “Ministerio de Economía y Competitividad” and XAA‐S by the Spanish MINECO Grant CTM2015‐ 69392‐C3‐2‐R. Data collection on U.S. CLIVAR sections and involvement by C. R.‐C. and D. A. H. were supported by U.S. NSF OCE1436748 Peer reviewed