The depth profiles reveal that benzene concentrations were generally higher in the top 75 m, along with elevated Chl a concentrations. The benzene profiles displayed concentrations of around 10 pmol dm -3 in the upper 200 m in low Chl a casts, and on average around 20 pmol dm -3 and 30 pmol dm -3 in the upper 75 m in the medium and high Chl a casts, respectively. Chl a and benzene depth profiles showed remarkable co-variation with depth across Chl a regimes.