The impacts of ocean acidification on marine trace gases and the implications for atmospheric chemistry and climate

• Published in: Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
• Main Authors: Hopkins, Frances E., Suntharalingam, Parvadha, Gehlen, Marion, Andrews, Oliver, Archer, Stephen D., Bopp, Laurent, Buitenhuis, Erik, Dadou, Isabelle, Duce, Robert, Goris, Nadine, Jickells, Tim, Johnson, Martin, Keng, Fiona, Law, Cliff S., Lee, Kitack, Liss, Peter S., Lizotte, Martine, Malin, Gillian, Murrell, J. Colin, Naik, Hema, Rees, Andrew P., Schwinger, Jörg, Williamson, Philip
• Other Authors: Norges Forskningsråd, Ministry of Education Malaya, New Zealand CARIM, Scientific Committee on Ocean Research, National Research Foundation of Korea, Natural Environment Research Council, MTES/FRB Acidoscope, Natural Sciences and Engineering Research Council of Canada, Phase II Higher Institution Centre of Excellence Fund, Ministry of Education Malaysia, H2020 Environment, Universiti Malaya
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 2020
• Subjects: Ocean acidification
• Online Access: http://dx.doi.org/10.1098/rspa.2019.0769; https://royalsocietypublishing.org/doi/pdf/10.1098/rspa.2019.0769; https://royalsocietypublishing.org/doi/full-xml/10.1098/rspa.2019.0769

Surface ocean biogeochemistry and photochemistry regulate ocean–atmosphere fluxes of trace gases critical for Earth's atmospheric chemistry and climate. The oceanic processes governing these fluxes are often sensitive to the changes in ocean pH (or p CO 2 ) accompanying ocean acidification (OA), with potential for future climate feedbacks. Here, we review current understanding (from observational, experimental and model studies) on the impact of OA on marine sources of key climate-active trace gases, including dimethyl sulfide (DMS), nitrous oxide (N 2 O), ammonia and halocarbons. We focus on DMS, for which available information is considerably greater than for other trace gases. We highlight OA-sensitive regions such as polar oceans and upwelling systems, and discuss the combined effect of multiple climate stressors (ocean warming and deoxygenation) on trace gas fluxes. To unravel the biological mechanisms responsible for trace gas production, and to detect adaptation, we propose combining process rate measurements of trace gases with longer term experiments using both model organisms in the laboratory and natural planktonic communities in the field. Future ocean observations of trace gases should be routinely accompanied by measurements of two components of the carbonate system to improve our understanding of how in situ carbonate chemistry influences trace gas production. Together, this will lead to improvements in current process model capabilities and more reliable predictions of future global marine trace gas fluxes.