The data set comprises hydrographic and biogeochemical and biological measurements including temperature, salinity, currents, chlorophyll, dissolved organic and inorganic carbon and nitrogen, suspended matter concentrations, nutrients, plankton and fish. The results of primary production experiments are also included. The data were collected from the Bristol Channel, Severn Estuary, Celtic Sea and Plymouth Sound between 1971 and 1983. Measurements were taken over a series of more than 100 cruises, many with more than 50 stations. The most intensive sampling took place before 1975. The original data were collated and stored at Institute for Marine Environmental Research (IMER), which became Plymouth Marine Laboratory in 1988. As this is a large and important data set, which was previously held in an inaccessible format, it was selected for long-term archival at BODC as part of the NERC SEEDCORN programme. The data have been extracted, loaded into a relational database and are available on CD-ROM.

The dataset comprises physical, biogeochemical and biological measurements of water column properties. Hydrographic profiles of water temperature, salinity, fluorescence, turbidity, attenuance, dissolved oxygen and photosynthetically active radiation were collected, and were supplemented by measurements of surface ocean (temperature, salinity, fluorescence, attenuance) and meteorological (air pressure, air temperature, humidity, wind, irradiance) properties, as well as bathymetry. A comprehensive water sampling program provided biogeochemical data including measurements of dimethyl sulphide (DMS), dimethylsulphionopropionate (DMSP), nutrients, halocarbons, methylamines, pigments, radiogeochemistry and dissolved organic carbon (DOC). Biological data were also collected, including samples of viruses, bacteria, phytoplankton, micro- and mesozooplankton. Currents throughout the water column were measured both at fixed locations and across the study area, while Lagrangian experiments provided further current data. The datqa were collected in the northern North Sea between 5th June 1999 and 1st July 1999 during RRS Discovery cruise D241. Hydrographic profiles were collected using a conductivity-temperature-depth (CTD) package with attached auxiliary sensors, an undulating oceanographic recorder (UOR), a vessel-mounted acoustic Doppler current profiler (ADCP), moored ADCP and temperature sensors, and a suite of standard underway hydrographic and meteorological sensors. Water samples for biogeochemical and biological analyses were collected from both the underway system and CTD bottles, while nets were deployed to collect zooplankton samples. Plankton samples were supplemented by respiration experiments conducted during the cruise. The Lagrangian current data were gathered from four drifters and a tracer experiment where the distribution of sulphur hexafluoride (SF6) released from the ship was monitored via water samples collected from the CTD and the underway system. A survey of the region was carried out in order to locate an Emiliania huxleyi bloom suitable for the study and the chosen bloom was labelled with the SF6 tracer. The biogeochemical process study followed the patch as it drifted in a SE direction and was eventually subducted under Norweigian coastal water on 26 June. The study aimed to investigate DMS biogeochemistry within a coccolithophore bloom. The research was organised by NERC's Plymouth Marine Laboratory and involved the University of East Anglia, Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Marine Biological Association, Defence Research Agency, and Southampton Oceanography Centre. Data management support for the project is provided by the British Oceanographic Data Centre (BODC). The dataset is available on CD-ROM and can be requested from BODC.

The data set comprises a diverse collection of physical, chemical and biological measurements, encompassing over 1000 parameters. There are data from over 1650 conductivity-temperature-depth (CTD)/rosette stations, over 300 core profiles, over 370 sediment trap samples and much, much more. Most of this effort was directed at the region of the east Atlantic margin between La Chapelle Bank and the Goban Spur (between France and Ireland). In addition, there were two secondary areas of interest: the Norwegian Shelf Break just off Tromso and the Iberian Margin, either off Vigo or in the vicinity of the Tagus estuary. Measurements were collected from April 1993 until the end of December 1995 during 55 research cruise legs. Data were collected using a variety of equipment and techniques, including expendable bathythermography (XBTs), CTDs and oceanographic undulators with auxiliary sensors. These hydrographic profiles were accompanied by net hauls, plankton recorder deployments, sediment cores and comprehensive water and air sampling programmes during which a wide variety of chemical and biological parameters were measured. The station data were supplemented by underway measurements of oceanographic and meteorological properties. Results from production and trace metal experiments are also included in the dataset, as are bathymetric data from the British Oceanographic Data Centre (BODC) GEBCO digital Atlas, air-sea flux measurements and data from moored instruments and benthic landers that were deployed for periods from a few weeks to a year. The dataset also includes imagery from satellites, water column and seabed photography, scanning electron micrographs and X-ray photographs. FORTRAN source code for biogeochemical models developed during OMEX I is also included. The aim of the project was to study biogeochemical processes at the shelf break and to quantify the fluxes of material between the shelf and the open ocean. OMEX I involved scientists from 30 institutions in 10 countries. BODC is assembling the data sets collected during OMEX I into its database system and the data are also available on CD-ROM.