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Concentration of alkanes in the water column

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  • This dataset comprises 120 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, during November - December 1994 from stations in the Gulf of Oman and the Arabian Sea. A complete list of all data parameters are described by the SeaDataNet Parameter Discovery Vocabulary (PDV) keywords assigned in this metadata record. The data were collected by the Plymouth Marine Laboratory as part of the ARABESQUE project.

  • This dataset comprises hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, in April 1989 from stations covering the southern North Sea (south of 56N). A complete list of all data parameters are described by the SeaDataNet Parameter Discovery Vocabulary (PDV) keywords assigned in this metadata record. The data were collected by the University of Southampton Department of Oceanography as part of the North Sea Project Blooms/Chemistry Process Study.

  • This dataset comprises 39 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, during November - December 1992 from the Bellingshausen Sea, Southern Ocean. A complete list of all data parameters are described by the SeaDataNet Parameter Discovery Vocabulary (PDV) keywords assigned in this metadata record. The data were collected by the James Rennell Centre for Ocean Circulation as part of the Biogeochemical Ocean Flux Study (BOFS).

  • This dataset comprises 167 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, during August - October 1994 from stations from the Straits of Hormuz to the Murray Ridge in the Gulf of Oman and the Arabian Sea. A complete list of all data parameters are described by the SeaDataNet Parameter Discovery Vocabulary (PDV) keywords assigned in this metadata record. The data were collected by the Plymouth Marine Laboratory as part of the ARABESQUE project.

  • The dataset comprises concentration of gas hydrates beneath the seabed, in the water column and, atmosphere along with the topography of the sea floor. Data were collected in the Arctic Ocean off the NorthWestern coast of Svalbard across the continental margin between 78 and 80 North and 4 and 11 East. The data were collected during cruise JR211 which, over two legs, took place between 23rd August 2008 and 24th September 2008. Geophysical and geological techniques were used to detect methane hydrate beneath the seafloor and to investigate features trough which methane escapes to the seafloor. The seabed was imaged and mapped using a multibeam sonar (Simrad EM120), an echosounder (Simrad EK60), TOBI deep-towed sidescan sonar (30 kHz), widescan sidescan sonar (100 and 350 kHz). The sedimentary layers and geological structures beneath the seabed were imaged with the 7 kHz profiler in TOBI, a TOPAS sub-bottom acoustic profiler and multichannel seismic reflaction (96 channels with 6.25 m group spacing) using two air guns in true GI mode 45/105 cu.in. More accurate information on seismic velocity was obtained by deploying ocean-bottom seismometers on the seabed which contained 3 Sercel L-28 4.5 Hz geophones and a High Tech HTI-90-U hydrophone. Sediment samples were obtained using a piston corer, a gravity corer and, a box corer. Water chemistry was measured from discrete samples taken from bottles attached to the conductivity-temperature-depth (CTD) sensor package and continuously from the ship's seawater supply. Methane concentration was measured on-board using a headspace technique. Air samples were collected at 12 hour intervals. Sampling occurred on the Navigation Bridge deck and the side of the ship upwind of the ships emissions was chosen each time. Additional samples were also collected close to the ship's funnel, to check for contamination, and from the gas released by the cores when in an inert atmosphere (N2). Analysis of methane mixing ratio is performed by Gas Chromatography - Flame Ionisation Detector (GC-FID) and the stable carbon isotopic composition of methane is analysed using a continuous flow Gas Chromatography - Isotope Ratio Mass Spectrometry (GC-IRMS) system. Almost half of the Earth's carbon is stored in gas hydrates and related shallow gas deposits. Numerical models predict that this reservoir is highly mobile and that escaping gas has a significant potential to accelerate climate change releasing as much as 2000 Gt of methane over a short period of time. As methane is a potent greenhouse gas it would course further global warming. Arctic gas hydrates are most vulnerable to future climate change because (1) it is predicted that temperatures will increase faster in the Arctic than in low latitudes (2) the intercept of the gas hydrate stability zone with the seabed is within the reach of fast warming surface waters and (3) the water column above the vulnerable zone of gas hydrates is smaller than in warmer oceans facilitating more efficient transport of greenhouse gases to the atmosphere. This information will allow a detailed assessment of the mobility of Arctic gas hydrates and it will significantly decrease the uncertainties involved in climate modelling. The data were collected by the National Oceanographic Centre, Southampton with Professor Tim Minshull as the principal scientist on-board.

  • This data set comprises hydrographic measurements including temperature, salinity, fluorescence, attenuance, dissolved oxygen concentrations and current velocities. Water samples were also collected for salinity and geochemical analysis, and the data set also includes bathymetric, sediment and upper ocean turbulence measurements. The data were collected over six Science Missions at the Strait of Sicily, West Coast of Scotland (Loch Etive and Loch Fyne), North-East Scotland and Shetland Islands, North Weddell Sea, Isles of Scilly, Southern North Sea (Norfolk Bank) over the period 19 April 1999 – 25 May 2001. The data were collected by both shipboard sensors and those attached to the Autosub (Autonomous Underwater Vehicle) package. Shipboard data collection included deployment of a conductivity-temperature-depth (CTD) package with attached auxiliary sensors. Lowered acoustic Dopper current profilers (LADCPs) were also attached to the CTD frame, while discrete water samples were collected from the CTD stations. Oceanographic, bathymetric and sediment data were collected along the ship’s track. Autosub measurements included standard environmental parameters and acoustic instruments were used to measure ocean bottom relief at high resolution. A camera was also attached to the vehicle, permitting the collection of detailed photographs of the seabed. The broad aims of the Autosub Programme are the collection of interdisciplinary data sets that cannot be obtained by research ships, and demonstration to the scientific and wider user community of the usefulness of an AUV. Investigators: David A Smeed, Kate Stansfield, Julian Overnell, Kenny D Black, Peter Statham, Chris German, Andrew S. Brierley, Paul G. Fernandes, Mark A. Brandon, Alex Cunningham, Peter Burkill, Glen Tarran, Prof. Mike Collins, Dr George Voulgaris, Dr John Trowbridge, Dr Eugene Terray, Steve A Thorpe and Thomas Osborn. The British Oceanographic Data Centre holds the Autosub navigation files, CTD and ADCP data for each of the missions listed above. The data are contained as high resolution time series. The data are presently being processed and have not been fully quality controlled. The Autosub science missions brought together researchers and engineers from a number of UK institutions, with the project being coordinated by the National Oceanography Centre, Southampton.

  • This dataset comprises 69 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, during May - June 2003 along the Atlantic Meridional Transect (AMT), a distance of almost 13,500 km, from the Falkland Islands to the UK. A complete list of all data parameters are described by the SeaDataNet Parameter Discovery Vocabulary (PDV) keywords assigned in this metadata record. The data were collected by the University of East Anglia School of Environmental Sciences as part of the Atlantic Meridional Transect (Phase 2) programme.

  • The data set comprises measurement of physical and biological oceanographic parameters initially collected as part of the Plankton Monitoring Programme at Station L4 from 1988 onwards. Station L4 located in the English Channel, 10 nautical miles south-west of Plymouth, is one of a series of hydrographic stations in the Western English Channel which have been the basis of a series of hydrographic surveys carried out during the 20th Century by scientists at the Marine Biological Association in Plymouth. In May 2002 sampling expanded to include Station E1, approximately 25 nautical miles south-west of Plymouth. Plankton Monitoring began through the work of the Plymouth Marine Laboratory (PML) Zooplankton Group. A long term time-series of weekly observations has been established by exploiting the activities of the PML small boats (Sepia, Squilla and Plymouth Quest) in a opportunistic way as by-product of their other sampling activities, for example the collection live plankton, sea-water, trawling for fish and squid. Initially no formal research programme or long term funding for the Plankton Monitoring existed but the series was included in NERC Oceans 2025 funding as a Sustained Observatory and continues to be funded under NERC National Capability. The programme has evolved to be known as the Western Channel Observatory (WCO). Although every attempt has been made to standardise methodology and achieve data consistency it is important to recognize that the varied personnel and research objectives that have contributed to this dataset may impact on the nature of the data set.

  • The dataset comprises hydrographic data, including salinity, temperature, depth, dissolved oxygen, transmittance (for suspended sediment), chlorophyll, irradiance, and current velocities. Both oceanographic and benthic measurements of nutrients (nitrate, nitrite, silicate, phosphate and ammonium), phytoplankton and zooplankton abundance, dissolved and particulate trace metals, primary and bacterial production, sulphur compounds and halocarbons were collected, as well as atmospheric physical and chemical measurements. The data were collected in the North Sea between August 1988 and October 1990 over a series of 38 cruises on RRS Challenger. Oceanographic measurements were taken using hydrographic profilers, moored instruments and shipboard underway systems. Underway meteorological data were also collected in addition to a comprehensive atmospheric sampling programme. Both continuous and discrete water samples were collected, providing biogeochemical and biological data. These were supplemented by net hauls. Benthic processes were investigated with sediment cores taken on eight survey cruises at six sites of varied character, three being in the area of summer stratification. Water and benthic sample analyses were supplemented by results of seabed and shipboard incubation experiments. The North Sea Project evolved from a NERC review of shelf seas research, which identified the need for a concerted multidisciplinary study of circulation, transport and production. The Proudman Oceanographic Laboratory (POL), now the National Oceanography Centre (NOC) hosted the project. It involved over 200 scientists and support staff from the Natural Environment Research Council (NERC), the Ministry of Agriculture, Fisheries and Food (MAFF - now DEFRA) and other academic institutes. The data are held at the British Oceanographic Data Centre and are available on CD-ROM.

  • The dataset comprises hydrographic profiles (temperature, salinity, oxygen, fluorometer, transmissometer, irradiance) and along track measurements (bathymetry, surface meteorology, sea surface hydrography), with discrete measurements including water chemistry (organic and inorganic nutrients, particulate organic carbon and nitrogen, dissolved gases, trace metals), biology (phytoplankton, zooplankton, primary production, community respiration, chlorophyll, pigments) and atmospheric particulates (major ions, organics and trace metals). Data have been collected from meridional transects of the Atlantic Ocean (between the UK and the Falkland Islands, South Africa or South America) from 1995 to the present day. The Atlantic Meridional Transect (AMT) programme aims to study the factors determining the ecological and biogeochemical variability of planktonic ecosystems in the tropical and temperate Atlantic Ocean, and their links to atmospheric processes. The majority of the data are available to academia for re-use and re-purpose but data from recent cruises may be subject to a moratorium which allows first use for data originators. The AMT is coordinated by Andy Rees (AMT Principal Investigator) and Miss Dawn Ashby (AMT Project Officer) at the Plymouth Marine Laboratory (PML) in conjunction with the National Oceanography Centre. Since its inception the programme has involved researchers from several different countries and has acted as a platform for national and international collaboration. Data are managed by the British Oceanographic Data Centre.