Ocean Margin Exchange (OMEX)

Deploying a zooplankton net
Deploying a zooplankton net ©

OMEX aims were to study, measure and model the physical, chemical and biological processes and fluxes happening at the ocean margin — the interface between the open  Atlantic ocean and the European continental shelf. It served as a basis for the development of predictive models of global environmental changes on the oceanic system and, more specifically, on the coastal zone.

Who ran the project?

OMEX was led by the late Professor Wollast from Université Libre de Bruxelles, Belgium and ran from 1993 to 2000. It brought together over 100 scientists from 40 research centres and universities throughout Europe. It was jointly funded by the European Union within the Marine Science and Technology (MAST) programme and contributions from participating countries.

BODC was responsible for the management of all data arising from the project.

Field campaign

The field data campaign of 80 research cruises took place in two of the three project phases along the European continental shelf. The studies included regions of both narrow-shelf and broad-shelf environments.

  • OMEX I was aimed at understanding, evaluating and modelling the processes happening along the northwest European shelf break. It collected extensive physical, chemical and biological measurements.

    A number of sites on the European continental margin were studied. The primary site was at the Goban Spur, to the south west of Cornwall, supported by comparison sites off northern Norway and Iberia. This phase ran from the beginning of April 1993 until the end of December 1995 and collected over 600 individual data sets during 47 research cruise legs.

  • OMEX II-II was a more intensive measurement and modelling study of the exchanges of matter and energy across the northwest Iberian Margin. All the fieldwork from this phase was undertaken in this area between June 1997 and October 1999.

Basic multidisciplinary measurements taken included

  • Physical (e.g. temperature, salinity, optics, current speed and direction)
  • Meteorology
  • Bathymetry
  • Chemical (e.g. nutrients, dissolved oxygen, organic carbon and nitrogen)
  • Biological (e.g. biomass, pigments and production)
  • Geological (sediment traps, cores)

OMEX II-I, also known as the ‘Bridging Phase’, ran from June 1996 until May 1997. This period was used to improve the outputs from OMEX I and to enhance the strategies for OMEX II-II.

How were the data collected?

Measuring equipment deployed during the OMEX cruises included

  • CTD — conductivity, temperature and depth profiles, along with other parameters.
  • Water bottles — water samples at specific depths.
  • Underway — continuous measurements of sea surface data (e.g. salinity, temperature, attenuance, chlorophyll, nutrients), meteorology, navigation and bathymetry.
  • Moored instruments — deployed in the ocean for a period of time and collected at a later stage (e.g. current meters, sediment traps and benthic landers).
  • Towed instruments — towed behind the ship (e.g. Continuous Plankton Recorder (CPR) and the Undulating Oceanographic Recorder (UOR)).
  • Swath and single-beam bathymetry.
  • Sea bed box and multicorers.

Further information about the project may be obtained from the official web site.

Data management goal

Our main goal was to provide harmonised management of the field data, both for the benefit of the project scientists and to ensure that OMEX left a legacy of fully documented archived data for comparative studies in years to come.

The data management challenges presented by OMEX were beyond anything attempted in the marine field before. BODC’s approach to the project's data management, an important element of any large programme, is now viewed internationally as a model for other projects to follow.

The OMEX data set

The data management activities resulted in the release of three CDROM publications

  • OMEX-I Project Data Set, a double CDROM, containing the final OMEX I project data. Published in 1997.
  • OMEX-I Final Report, a single CDROM, containing the final scientific reports written by the projects principal investigators. Published in 1997 but restricted to project participants.
  • OMEX-II Project Data Set, a triple CDROM, containing the final OMEX II project data. Published in 2001.

The data are also held in BODC’s databanks so subsets may also be obtained by request from  the BODC Enquiries Officer.

Ocean Margin Exchange  European Commision Marine Science and Technology