Departure of the French PEACETIME cruise in the Mediterranean Sea

The PEACETIME* cruise will depart on May 10 from La Seyne (France) for a 33 days cruise. Onboard the French oceanographic research vessel Pourquoi Pas ?, there will be a team of 40 scientists who will study the impact of atmospheric deposition on the ocean. This international and multidisciplinary scientific team will travel the central and western Mediterranean in search of atmospheric deposition of Saharan dust. Their aim is to study processes at the interface between the atmosphere and the ocean in this region of the world where atmospheric input plays a key role as a nutrient source for the marine biosphere. This campaign will allow to better understand how atmospheric deposition affects the functioning of the pelagic ecosystem in order to more accurately predict the future of biodiversity in the Mediterranean.

On board, the scientific team will combine in situ observations in the atmosphere and ocean with process studies in the water column. This will allow to characterize the chemical, biological and physical properties of the atmosphere, the marine surface micro-layer, and the deeper layers of the Mediterranean.

In order to optimize the chances of observing a deposition of Saharan dust in situ during the cruise, the cruise track is in a zone where the probability of this type of event is greatest. In the event of such an occurrence, the vessel will be diverted from its original transect to the identified deposit area. Another specific features of this campaign is to embark “climatic reactors” that are devices reproducing on a small scale the air-sea exchanges under current and future environmental conditions (acidification and increase of the temperature of the sea water).

This coordinated multidisciplinary effort will better characterize the impact of atmospheric deposition in the ocean and their feedback to the atmosphere in a nutrient-poor system such as the Mediterranean Sea. PEACETIME is a GEOTRACES Process-study (GApr09).

*PEACETIME: ProcEss studies at the Air-sEa Interface after dust deposition in the MEditerranean sea


Figures: (Left) The route of the PEACETIME oceanographic campaign in the central and western Mediterranean is indicated on this map as well as the planned observation stations. Click here to view the figure larger. (Right) Illustration of an event of transport of Saharan dust in the western Mediterranean, part of which is deposited at sea (seen by a satellite, NASA image).

Follow PEACETIME at: 

  • Web site:
  • Twitter: @peacetimecruise

Coordinators and Chief Scientist:

  • Cécile Guieu, CNRS Research Director, Laboratoire Océanographique de Villefranche-sur-Mer (LOV), France. 
  • Karine Desboeufs, Professor, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA)/Université Paris Diderot, Université Paris-Est Créteil.