@article{fdi:010085342, title = {{E}vidence for enhanced primary production driving significant {CO}2 drawdown associated with the {A}tlantic {ITCZ}}, author = {{I}banhez, {J}. {S}. {P}. and {M}ontes, {M}. {F}. and {L}ef{\`e}vre, {N}athalie}, editor = {}, language = {{ENG}}, abstract = {{T}he intense rainfall associated with the {I}ntertropical {C}onvergence {Z}one ({ITCZ}), a narrow zone of confluence of the northeast and southeast trades, can significantly alter sea surface salinity, the chemistry of inorganic {C} and the resulting sea-air {CO}2 exchange in the tropics. {W}e have analyzed extensive underway data collected from 2008 until 2014 and recorded by an autonomous {CO}2 system installed on a commercial ship that crosses the central tropical {A}tlantic (5 degrees {S} to 15 degrees {N}, 18 degrees {W} to 36 degrees {W}) to disentangle the effects of the {ITCZ} over the carbonate system there. {B}ased on statistically significant linear co-variance of sea surface fugacity of {CO}2 (f{CO}(2sw)) and sea surface salinity in the areas affected by the {ITCZ}, we calculated {CO}2 drawdown rates associated with the impact of the {ITCZ} in the central tropical {A}tlantic ranging from 0.11 +/- 0.02 to 2.35 +/- 0.08 mmol m(-2) d(-1). {T}hese were calculated by comparing the observed f{CO}(2sw) with that expected without surface seawater carbonate system dilution and increase in gas transfer caused by the {ITCZ}. {T}he observed decrease in f{CO}(2sw) associated with the freshening caused by the {ITCZ} is much larger than expected from thermodynamics alone. 59.1 +/- 4.1 % of the total observed {CO}2 drawdown associated with the {ITCZ} cannot be explained by abiotic processes. {I}nstead, we found significant negative correlations between underway sea surface salinity and remote-sensed chlorophyll a in the areas affected by the {ITCZ}. {D}ifferent to other tropical oceanic basins, the tropical {A}tlantic receives large amounts of continental dust originated from {A}frica. {W}et dust deposition driven by the {ITCZ} appears associated with the interannual variability of the {CO}2 drawdown associated with the {ITCZ}. {F}ertilization driven by the {ITCZ} seems to enhance primary production in the otherwise oligotrophic tropical {A}tlantic, thus significantly lowering {CO}2 emissions to the atmosphere.}, keywords = {{T}ropical {A}tlantic ; {O}ceanic carbonate system ; {S}ea-air {CO}2 flux ; {R}ainfall ; {D}iazotrophy ; {ATLANTIQUE} ; {ZONE} {TROPICALE}}, booktitle = {}, journal = {{S}cience of the {T}otal {E}nvironment}, volume = {838}, numero = {4}, pages = {156592 [15 ]}, ISSN = {0048-9697}, year = {2022}, DOI = {10.1016/j.scitotenv.2022.156592}, URL = {https://www.documentation.ird.fr/hor/fdi:010085342}, }