The European Science Foundation's (ESF) European Collaborative Research (Eurocores) programme Euromarc helps plan international marine coring expeditions.
It also helps prepare IODPs (Intergrated Ocean Drilling Programmes) or Images (International Marine Past Global Change Study).
The programme consists of seven collaborative research projects with principal investigators from nine countries.
Thick marine sediment sections are used to make reconstructions of the meridional overturning circulation in high and low latitudes and of the spatial and temporal structure of the interglacial peaks and demises.
Fossil reef and carbonate mounds cores are extracted to reconstruct sea-level and environmental changes.
Sediment traps help investigate current ocean dynamics and sediment fluxes.
Hydrothermal processes of deep biosphere at mid-ocean ridges are also explored.
A site survey cruise will often precede the main cruise to identify the best spots for coring and get the drill-sites approved by bodies such as IODP.
A multi-beam echo sounder system maps the topography of the seafloor, which is like a fanlike beam covering a huge swath of the seafloor.
Sediment penetrating systems shoot signals with varying energy pulses and wave lengths that hit the bottom and are differently reflected, depending on the density of the layers, giving a detailed impression of the layering of the sediments.
Autonomous underwater vehicles are often used for more local surveys.
Gilbert Camoin from CNRS in Aix-en-Provence, chair of Euromarc's scientific committee and project leader of CHECREEF (The Last Deglacial Sea-Level and Climatic Changes) investigates coral reefs in Tahiti and the Great Barrier Reef.
He said: 'To make sure we won't damage any living ecosystem, we drop an underwater camera to see the nature of the seafloor just around the potential drilling site.' The regulations for drilling are strict and pictures are taken before and afterwards.
Camoin said: 'There is no impact at all, when you pull up the pipes, the hole just collapses and it's even impossible to find it again.' On the main cruise, the coring itself takes place as well as first measurements and part of the sampling.
The cores are extracted in different ways, at different water depths and of different lengths, depending on the sediments and the objectives.
Short cores of less than 1.5m are often used to drill coral reefs, long cores are needed if there are high sedimentation rates going back in time.
Box coring and the multicores instrument take surface samples.
With the multicores instrument, even the water above the sediment is captured.
Once a core is on board, its dimensions are measured.
Longer cores are cut into segments, then split into two halves, the archive half and the working half, and the first preliminary, non-destructive on-site analyses are made, such as the core description including photos, microbial activity tests and the measurement of the physical properties in a multi-sensor core logger.
The cores are then stored and cooled in containers before undergoing more sampling procedures.
On the cruises, the expeditions are up to two months long and research is carried out around the clock: the members of the scientific crew do two four-hour shifts a day.
Amocint had five teachers on board that participated in the 'Teachers at Sea' programme of EGU-IPEV (European Geoscience Union-Institut Paul-Emile Victor).
As not all techniques can be run on board, the sampling is either done in the individual labs or as a joint activity in the form of a science sampling party, as happened in Bremen.
The scientists receive numerous sampling requests from their community and have to divide their labour.
If the cores are sampled in different labs, the results are usually shared to avoid duplicate sampling.
Good recovery of the cores in marine coring and drilling is essential: sometimes the sediment is lost when pulling out the core and when the core-catcher at the bottom doesn't shut.
