Mari Xavier auteur aut IRD Lefèvre Jérôme auteur aut IRD Torréton Jean-Pascal auteur aut IRD Bettarel Yvan auteur aut IRD Pringault Olivier auteur aut IRD Rochelle Newall Emma auteur aut IRD Marchesiello Patrick auteur aut IRD Menkès Christophe auteur aut IRD Rodier Martine auteur aut IRD Migon C. auteur aut IRD Motegi C. auteur aut IRD Weinbauer M. G. auteur aut IRD Legendre L. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Large amounts of soot are continuously deposited on the global ocean. Even though significant concentrations of soot particles are found in marine waters, the effects of these aerosols on ocean ecosystems are currently unknown. Using a combination of in situ and experimental data, and results from an atmospheric transport model, we show that the deposition of soot particles from an oil-fired power plant impacted biogeochemical properties and the functioning of the pelagic ecosystem in tropical oligotrophic oceanic waters off New Caledonia. Deposition was followed by a major increase in the volume concentration of suspended particles, a change in the particle size spectra that resulted from a stimulation of aggregation processes, a 5% decrease in the concentration of dissolved organic carbon (DOC), a decreases of 33 and 23% in viral and free bacterial abundances, respectively, and a factor similar to 2 increase in the activity of particle-attached bacteria suggesting that soot introduced in the system favored bacterial growth. These patterns were confirmed by experiments with natural seawater conducted with both soot aerosols collected in the study area and standard diesel soot. The data suggest a strong impact of soot deposition on ocean surface particles, DOC, and microbial processes, at least near emission hot spots. specialized NOUVELLE CALEDONIE 032 036 28 7 662-678 2014 0886-6236 https://www.documentation.ird.fr/hor/fdi:010062483 10.1002/2014gb004878 0886-6236 [F B010062483] https://www.documentation.ird.fr/hor/fdi:010062483 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers15-08/010062483.pdf IRD - Base Horizon / Pleins textes 2014-10-02 2021-04-07 fdi:010062483 fre