The impacts of ocean acidification on marine trace gases and the implications for atmospheric chemistry and climate
Résumé
Surface ocean biogeochemistry and photochemistry regulate ocean–atmosphere fluxes of tracegases critical for Earth’s atmospheric chemistry and climate. The oceanic processes governingthese fluxes are often sensitive to the changes in ocean pH (orpCO2) accompanying oceanacidification (OA), with potential for future climate feedbacks. Here, we review currentunderstanding (from observational, experimental and model studies) on the impact of OAon marine sources of key climate-active trace gases, including dimethyl sulfide (DMS), nitrousoxide (N2O), ammonia and halocarbons. We focus on DMS, for which available information isconsiderably greater than for other trace gases. We highlight OA-sensitive regions such as polaroceans and upwelling systems, and discuss the combined effect of multiple climate stressors(ocean warming and deoxygenation) on trace gas fluxes. To unravel the biological mechanismsresponsible for trace gas production, and to detect adaptation, we propose combining processrate measurements of trace gases with longer term experiments using both model organismsin the laboratory and natural planktonic communities in the field. Future ocean observationsof trace gases should be routinely accompanied by measurements of two components of thecarbonate system to improve our understanding of howin situcarbonate chemistry influencestrace gas production. Together, this will lead to improvements in current process modelcapabilities and more reliable predictions of future global marine trace gas fluxes.
Origine : Publication financée par une institution
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