Phaeopigment concentrations in sediment
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The dataset contains hydrographic, biogeochemical and biological measurements of ocean and seabed sediment properties. Hydrographic profiles provided measurements of temperature, salinity, dissolved oxygen and fluorescence to accompany biogeochemical and biological samples, including concentrations of nutrients, particulate organic carbon (POC) and particulate organic nitrogen (PON). Emphasis was placed on the collection of benthic data, with numerous core samples being collected and analysed for pigments, biomarkers, lipids and other organic compounds. Samples were also collected and analysed for Holothurian species, while a large volume in situ filtration system was used to measure biogeochemical variables including POC and PON, and particulate iron. Station data were supplemented by continuous underway measurements of bathymetry, current velocities, sea surface salinity, temperature, fluorescence and beam attenuation across the survey area. These were accompanied by underway measurements of surface meteorological parameters including irradiance, air temperature, humidity, sea level pressure and wind velocities. The data were collected across the Crozet Plateau in the Southern Indian Ocean between 1st December 2005 and 14th January 2006 on RRS Discovery cruise D300. Data collection focused on four sites, with repeated hydrographic profiles, water and sediment samples collected at each location. In total, 89 instrumentation deployments were carried out at the four stations, including a conductivity-temperature-depth (CTD) package and a Megacorer (for sediment sampling). The underway system utilised a hull-mounted acoustic Doppler current profiler (ADCP) as well as a thermosalinograph and other standard surface hydrographic and meteorological instruments. Further data were collected using a variety of equipment including an otter trawl (net) and submersible cameras but these data are currently held by the data originators and are undergoing processing so are not included in the parameter and instrument lists above. The principal objective of Benthic CROZEX was to assess the manner in which biogeochemical composition and flux of organic matter to the deep-sea floor drives benthic community structure, dynamics and diversity at sites with contrasting primary production regimes. Investigators from British Antarctic Survey (BAS), Natural History Museum (NHM), National Oceanographic Centre (NOC) and the National University of Ireland, Galway (NUIG) were involved. Data management is being undertaken by the British Oceanographic Data Centre (BODC) but data processing is ongoing and various data are yet to be submitted to BODC.
The dataset includes a wide range of physical, chemical and biological oceanographic parameters. Physical hydrographic measurements include temperature, salinity, optical backscatter, current velocities and turbulence, while biogeochemical measurements in the water column include dissolved oxygen, organic carbon and nitrogen, and nutrients. Biogeochemical parameters were also measured in sediment cores, while phytoplankton and zooplankton data were also collected. The marine data were supplemented by meteorological measurements including temperature, pressure, irradiance and wind. The experimental phase of the project was undertaken in the North Sea between 1998 and 1999, and data were collected at two contrasting sites: Northern North Sea (NNS, 59deg 20.0E, 1deg 00.0E) and Southern North Sea (SNS, 52deg 15.0N, 4deg 17.0E). At both locations measurements were concentrated at a central position with additional measurements being made to estimate horizontal gradients. Moored instruments were deployed at NNS from September - November 1998 and at SNS from March - May 1999. Each experiment was supported by intensive measurement series made from oceanographic ships and involving turbulence dissipation profiler, conductivity-temperature-depth (CTD) profilers, particle size profilers, optical profilers, benthic sampling and water bottle sampling. PROVESS is an interdisciplinary study of the vertical fluxes of properties through the water column and the surface and bottom boundary layers with the aim of improving understanding and quantification of vertical exchange processes in the water column. Scientists from 18 institutions distributed in 8 European countries participated in the fieldwork and modelling parts of the programme and was co-ordinated by John Howarth of the Proudman Oceanographic Laboratory. The British Oceanographic Data Centre (BODC) is responsible for assembling the data collected during the project into a comprehensive data set. The data has been organised onto a CD-ROM product available through BODC.
The data set comprises a diverse collection of physical, chemical and biological measurements, encompassing well over 1000 parameters. There are data from over 1000 conductivity-temperature-depth (CTD)/rosette stations, over 440 core profiles, over 180 sediment trap samples, over 140 net hauls and much, much more. The primary study area was a box extending to the base of the slope from Vigo to Cap Finistere. However, data are included from both further offshore (filament tracking) and from the Portuguese Margin. Measurements were taken from November 1996 to October 1999 during 33 cruise legs, involving research vessels from seven nations. Data were collected using a variety of equipment and techniques, including expendable bathythermographs (XBTs), turbulence probes, CTDs and oceanographic undulators with auxiliary sensors. These hydrographic profiles were accompanied by net hauls, plankton recorder deployments, sediment cores and a comprehensive water 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 phosphate uptake experiments are also included in the dataset, as are bathymetric data from multibeam (swath) surveys, coastal upwelling measurements and data from moored instruments and benthic landers. The dataset also includes imagery from satellites, seabed photography and X-ray photographs of core samples. The aim of the project was study biogeochemical processes at the shelf break and to quantify the fluxes of material between the shelf and the open ocean. The project brought together over 100 scientists from 40 research centres and universities throughout Europe. The British Oceanographic Data Centre (BODC) is assembling the data sets collected during OMEX II into its project database system and the data set is also available on CD-ROM.