The dataset comprises a diverse set of physical, chemical and biological data including: bacteria, carbon, chlorophyll, dissolved gases, light levels, nutrients, phytoplankton, productivity, respiration, salinity, temperature, trace elements and zooplankton. Measurements were gathered from the North Atlantic and Norwegian fjord waters between 1971 and 1998. The data arise from three sources: biological and hydrographic data collected between 1971 and 1975 at Ocean Weather Ship (OWS) India in the North Atlantic; conductivity-temperature-depth (CTD) casts, water samples, net samples and meteorological data from the four week Bergen Mesocosm experiment at Espegrend Marine Biological Field Station (Norway) in 1995; and the six week RRS Discovery cruise 221 to the North East Atlantic in 1996, where physical, chemical and biological data were collected. The data were collected using a variety of methods including: more than 500 CTD and SeaSoar profiles; nearly 1000 water bottle samples; over 600 net hauls; over 450 Secchi disk deployments; nearly 4000 multisizer samples; 23 production experiments; four drifting buoy tracks and 40 days of weather observations. The PRIME programme aimed to lay the basis for mathematical models to describe the role of plankton in biogeochemical fluxes within the oceans which have implications for climate regulation. The project was hosted by the School of Ocean Sciences, University of Wales, Bangor. Data management was undertaken by the British Oceanographic Data Centre and over 95% of the data collected are now assembled on a CD-ROM. The data are accompanied by an extensive users' guide (covering sampling protocol documentation), the structures used to store the data, and the data interrogation tools.

The programme involved two major fieldwork activities: a deep ocean research cruise and a programme of freshwater studies. The marine component of the dataset generated a total of 430 distinct variables, quantifying the meteorology, hydrography, chemistry, biogeochemistry, and the microbial plankton (bacteria, phytoplankton and microzooplankton) biomass, taxonomic composition along the 5500 km cruise track in the Indian Ocean during August-September 2001. Measurements were mainly made on water samples collected either from the sea surface while the ship was underway or from a range of depths during conductivity-temperatue-depth (CTD) and water sampling stations at each of 11 sites occupied in the Indian Ocean. The maximum depth sampled at open ocean sites ranged from 300 to 3000 m. Short sections of 300 m deep CTD and fluorescence profiles were also obtained using a moving vessel profiler (MVP). The freshwater component of the dataset generated variables from Priest Pot in the Lake District and from a range of other freshwater sites around the UK. It contains underpinning weekly time-series measurements characterising the physical, chemical and biological condition of the water column at the Priest Pot sampling site between 2002-2004, together with data from studies focused on the seasonal and spatial dynamics of viruses, bacteria and picophytoplankton, trace metal distribution and the ubiquity of microbial protists. The database also contains 376 gene sequences from genetic material extracted from environmental samples. The programme was a 5-year Thematic Programme funded by the Natural Environment Research Council (NERC) and the purpose of the study was to improve understanding of aquatic microbial biodiversity, with the emphasis on community interactions, ecosystem function (e.g. biogeochemical cycling of carbon and nutrients, and the potential for biotechnological exploitation. The programme involved scientists from the Plymouth Marine Laboratory, the National Oceanography Centre Southampton, University of Cardiff School of Biosciences, University of Cardiff School of Earth and Ocean Sciences, University of Warwick School of Biological Sciences, University of Newcastle School of Civil Engineering and Geosciences, University of Bristol School of Biological Sciences, University of Oxford Department of Zoology, University of Liverpool School of Biological Sciences, University of Stirling School of Biological and Environmental Sciences, the Marine Biological Association of the UK, Lancaster University Department of Environmental Science and the Centre for Ecology and Hydrology (CEH) Lancaster and Dorset.

The data set comprises hydrographic, biogeochemical and biological data, including measurements of temperature, salinity and attenuance, plus concentrations of parameters such as nutrients, pigments, urea, hydrocarbons, sedimentation flux, sulphur and dissolved carbon. Analyses of bacterial, zooplankton and phytoplankton communities were also undertaken. The oceanographic data were supplemented by measurements of surface meteorological parameters. Data were collected across three repeated sections: one along the Gulf of Oman; a section at 67deg East from 8 to 14.5deg North; and a major section from 8deg North, 67 deg East to the coast of Oman. Other one-off sections were also traversed in the Arabian Sea and Gulf of Oman areas. Measurements were collected during two cruises: one between 27 August and the 4 October 1994 and the other between the 16 November and the 19 December 1994. Sections were covered by underway surface ocean measurements (one minute sampling of multiple parameters providing some 5 million measurements) complemented by a total of 21 CTD/water-bottle stations, 14 of which were repeated. ARABESQUE was organised by the Plymouth Marine Laboratory of NERC's Centre for Coastal and Marine Sciences and involved the University of Wales, Bangor; Queen's University of Belfast; University of East Anglia; University of Edinburgh; University of Newcastle; the Bedford Institute of Oceanography, Canada; the Max Planck Institute for Limnology, Germany and the Sultan Qaboos University, Oman. Data management support for the project was provided by the British Oceanographic Data Centre. All data collected as part of the project were lodged with BODC who had responsibility for assembling, calibrating, quality controlling and fully documenting the data. BODC checked for instrument spikes or malfunction, values beyond the calibration range, unreasonable ratios of chemical constituents and unreasonable deviations from climatological means. Data were assembled into a relational database, complete with supporting documentation and a user manual. The full data set has been published by BODC on CD-ROM complete with user interface.