We conducted microcosm incubation experiments in contrasting biogeochemical areas of the South Indian Ocean and Indian sector of the Southern Ocean to determine the phytoplankton response to aerosol related nutrient release. Dry depositions of 2 mg.L-1 of dust from Patagonia or 25 mg.L-1 of ash from the Icelandic stratovolcano Eyjafjallajökull were added to trace metal clean incubations of surface seawater, along with nutrients (Si, Fe, N or P) at five stations. We interpreted the biological response based on abiotic experiments of aerosols nutrient release. We showed that both types of aerosols increased significantly the primary production by resolving some main local nutrient limitations of the Southern Ocean, at least for iron and to a lesser extend for silicon. Phytoplanktonic communities reacted differently to the additions; however added nutrients/aerosols were mostly beneficial for diatom growth, responsible for 40 to 100 % of the algal biomass increase, depending on the region and aerosols. Nonetheless, the aerosols did not relieve main N limitation of the LNLC area, as neither dust nor ash released significant amounts of NOx. According to these findings, characteristic localized high deposition of volcanic eruptions be of equal or higher importance to phytoplankton compared to desert dust, despite ashes’ lower nutrient solubility to the ocean.