The Mediterranean Sea is submitted to a continuous atmospheric flux of particles coming from anthropogenic activities as well as to pulsed fluxes of particles coming particularly from the Sahara Desert as well as from forest fires. These particles get transported through the atmosphere and get deposited on coastal and open ocean surface. To date, most studies on the impact of aerosol deposition on marine ecosystems in the Mediterranean Sea have focused on Saharan dust. The flux and impact of anthropogenic aerosols has so far been poorly explored although its importance as a source of mineral nutrients to the surface ocean has been recognized. Generally speaking, the combustion of organic matter releases to the atmosphere diverse organic compounds such as hydrocarbons, organic acids or ceto-acids which effect on marine ecosystems remains unknown.
The main goals of PARTICULE are to quantify the atmospheric flux of anthropogenic particles and derived organic matter and to assess their fate in the marine water column in PACA region.
The project is co-funded by PACA region, Labex OT-Med and MERMEX for the acquisition of atmospheric and seawater sampling devices. Aerosol sampling is being conducted continuously at the Endoume station for analyzing organic compounds including phthalates, organic acids and hydrocarbons. In addition, a one-year survey of the stoichiometric ratios and enzymatic activities in organic matter from atmospheric deposition has just started (MOOSE atmospheric station at Frioul Island, NW Mediterranean Sea). Experimental simulations of aerosol inputs to coastal seawater will be launched soon in order to follow the fate of aerosol-derived organic compounds in the water column under controlled conditions.
The research activities of PARTICULE are included in WP4 of MERMEX (Air-Sea interactions) and WP5 of CHARMEX (Atmospheric deposition of elements of biogeochemical interest), participating to the intention of OT-Med to significantly contribute to the meta-program MISTRALS launched by the French national research structures working on the Mediterranean region. This proposal also aims at contributing to the priorities of the Labex OT-Med, particularly the WP1 “Understanding and evaluating Mediterranean climatic changes and natural hazards” which includes an action on air-sea interactions with a focus on the effects of changes in aerosol deposition on biogeochemical processes.