Latitudinal variability in dissolved black carbon isotopic composition in Atlantic surface waters compared to atmospheric pyrogenic carbon inputs
Résumé
The main sources of pyrogenic carbon (PyC) to the ocean are rivers and aerosols. The Atlantic Ocean not only receives substantial riverine inputs but also substantial atmospheric PyC inputs from massive grassland wildfires. The Atlantic Ocean thus constitutes an ideal test bench to assess the impact of atmospheric PyC inputs on the dissolved black carbon (DBC) concentration and isotopic composition in open ocean surface waters. Here we show the DBC distribution in surface waters along a latitudinal transect across the Atlantic Ocean. This latitudinal transect includes areas subject to large inputs of atmospheric PyC from Africa. We quantified and characterized the stable carbon isotopic composition of DBC using the benzene polycarboxylic acid (B6CA and B5CA) method and compared the observed results with satellite estimates of PyC to assess the contribution of aeolian inputs to the oceanic DBC.