Polycyclic aromatic hydrocarbons (PAHs), and other semivolatile aromatic-like compounds (SALCs), are an important and ubiquitous fraction of organic matter in the environment which fate in the ocean remains uncharacterized. Here, we report a global assessment of the occurrence and atmosphere–ocean fluxes of 64 PAHs analyzed in paired atmospheric and seawater samples from the Atlantic, Pacific and Indian Oceans. The global atmospheric input of PAHs to the ocean is estimated at 0.09 Tg per month, four times greater than the Deepwater Horizon spill. The environmental concentrations of total SALCs were 102–103 times higher, with a relevant contribution of an aromatic unresolved complex mixture. These concentrations drive a global deposition of carbon estimated at 400 Tg C yr-1, around 15% of the oceanic carbon uptake due to CO2. Furthermore, we identify the biological pump and microbial degradation as key sinks of aromatic hydrocarbons in the oceans. Plankton and seawater samples showed lower concentrations of the hydrophobic compounds in the seawater when plankton biomass was higher, consistent with the relevance of the biological pump. However, the mass balance for the global oceans showed that settling fluxes of aromatic hydrocarbons in the water were 2 orders of magnitude lower than atmospheric deposition. This imbalance was even higher for low molecular weight hydrocarbons. These observations show the relevance of PAHs degradation processes in the oligotrophic oceans. Firstly, photochemical degradation may affectc in the photic layer, with negative correlations found between the dissolved concentrations of the lighter PAHs and light. Nevertheless, these correlations were weak explaining the concentrations variability, and the diagnostic ratios used for photochemistry were neither correlated with solar radiation. Alternatively, microbial degradation appeared to be the key factor for the depletion of the bioavailable hydrocarbons. We quantified the relative abundance of PAHs-degrading genes by analyzing the frequency of the alpha and beta subunits of RHD (specific biomarkers of PAH degradation) in the public metagenomic database of the oceanographic expedition Tara Oceans. Degradation genes for PAHs were found to be ubiquitous. The several lines of evidence provided support a relevant microbial degradation of PAHs, and also relevant for the largest SALCs organic carbon pool. It has been reported that large oligotrophic oceanic regions are heterotrophic, requiring sources of allochthonous organic matter. According to this work, degradation of atmospheric inputs of aromatic compounds is quantitatively relevant for the marine carbon cycle, and could help explain the observed heterotrophy of the oligotrophic oceans.