Enhanced mercury reduction in the South Atlantic Ocean during carbon remineralization. (May 2022)

• Record Type: Journal Article
• Authors: Živković, Igor; Humphreys, Matthew P.; Achterberg, Eric P.; Dumousseaud, Cynthia; Woodward, E. Malcolm S.; Bojanić, Natalia; Šolić, Mladen; Bratkič, Arne; Kotnik, Jože; Vahčič, Mitja; Obu Vazner, Kristina; Begu, Ermira; Fajon, Vesna; Shlyapnikov, Yaroslav; Horvat, Milena
• Is Part Of: Marine pollution bulletin. Volume 178(2022)
• Publication Date: 2022-05
• Subjects: Mercury -- Dissolved gaseous mercury -- Dissolved inorganic carbon -- South Atlantic Ocean -- Organic matter remineralization; Marine pollution -- Periodicals; Marine Biology -- Periodicals; Water Pollution -- Periodicals; Mer -- Pollution -- Périodiques; Publications périodiques; Pollution des mers; Lutte antipollution; Electronic journals; 363.7394
• DOI: 10.1016/j.marpolbul.2022.113644
• Languages: English
• ISSNs: 0025-326X

Abstract

Abstract: Mercury (Hg) in seawater is subject to interconversions via (photo)chemical and (micro)biological processes that determine the extent of dissolved gaseous mercury (DGM) (re)emission and the production of monomethylmercury. We investigated Hg speciation in the South Atlantic Ocean on a GEOTRACES cruise along a 40°S section between December 2011 and January 2012 (354 samples collected at 24 stations from surface to 5250 m maximum depth). Using statistical analysis, concentrations of methylated mercury (MeHg, geometric mean 35.4 fmol L −1 ) were related to seawater temperature, salinity, and fluorescence. DGM concentrations (geometric mean 0.17 pmol L −1 ) were related to water column depth, concentrations of macronutrients and dissolved inorganic carbon (DIC). The first-ever observed linear correlation between DGM and DIC obtained from high-resolution data indicates possible DGM production by organic matter remineralization via biological or dark abiotic reactions. DGM concentrations projected from literature DIC data using the newly discovered DGM–DIC relationship agreed with published DGM observations. Graphical abstract: Unlabelled Image Highlights: Dissolved gaseous mercury can be calculated from modeled dissolved inorganic carbon. Modeled dissolved gaseous mercury agrees well with worldwide observations. Dissolved gaseous mercury is related to depth and macronutrients concentrations.