Abstract
Mesoscale eddies are abundant in the global oceans and known to affect
marine biogeochemistry. Understanding their cumulative impact on the
air-sea carbon dioxide (CO2) flux is likely important
for quantifying the ocean carbon sink. Here, observations and Lagrangian
tracking are used to estimate the air-sea CO2 flux of 67
long lived (i.e. > 1 year) mesoscale eddies in the South
Atlantic Ocean over a 16 year period. We find that anticyclonic eddies
originating from the Agulhas retroflection and cyclonic eddies
originating from the Benguela upwelling act as net CO2
sinks over their lifetimes. In combination, the eddies significantly
enhanced the CO2 sink into the South Atlantic Ocean by
0.08 ± 0.01%. Although this modification appears small, long lived
eddies account for just ~0.4% of global ocean eddies
and eddy activity is increasing; therefore, explicitly resolving eddy
processes within all models used to assess the ocean carbon sink would
appear critical.