Anthropogenic CO2 changes in the Equatorial Atlantic Ocean. (May 2015)

• Record Type: Journal Article
• Authors: Fajar, N.M.; Guallart, E.F.; Steinfeldt, R.; Ríos, A.F.; Pelegrí, J.L.; Pelejero, C.; Calvo, E.; Pérez, F.F.
• Is Part Of: Progress in oceanography. Volume 134(2015:May)
• Page Start: 256
• Page End: 270
• Publication Date: 2015-05
• Subjects: Oceanography -- Periodicals; 551.4605
• DOI: 10.1016/j.pocean.2015.02.004
• Languages: English
• ISSNs: 0079-6611

Abstract

Highlights: Anthropogenic CO2 inventories in the Equatorial Atlantic range from 45 to 59 mol m −2 in 2010. Noticeable C ant increment (0.18 ± 0.03 μmol kg −1 y −1 ) and eastward extension in the 1000–2000 m horizon. Changes in circulation patterns produce a faster C ant storage rates than the expected in a steady state ocean. Abstract: Methods based on CO2 and chlorofluorocarbon (CFC) data are used to describe and evaluate the anthropogenic CO2 ( C ant ) concentrations, C ant specific inventories, and C ant storage rates in the Equatorial Atlantic Ocean. The C ant variability in the water masses is evaluated from the comparison of two hydrographic sections along 7.5°N carried out in 1993 and 2010. During both cruises, high C ant concentrations are detected in the upper layers, with values decreasing progressively towards the deep layers. Overall, the C ant concentrations increase from 1993 to 2010, with a large increment in the upper North Atlantic Deep Water layer of about 0.18 ± 0.03 μmol kg −1 y −1 . In 2010, the C ant inventory along the whole section amounts to 58.9 ± 2.2 and 45.1 ± 2.0 mol m −2 using CO2 and CFC based methods, respectively, with most C ant accumulating in the western basin. Considering the time elapsed between the two cruises, C ant storage rates of 1.01 ± 0.18 and 0.75 ± 0.17 mol m −2 y −1 (CO2 and CFC based methods, respectively) are obtained. Below ∼1000 m, these rates follow the pace expected from a progressive increase of C ant at steady state; above ∼1000 m, C ant increases faster, mainly due to the retreat of the Antarctic Intermediate Waters.