This dataset consists of 20 CTD cast profiles from 20 stations in the Whittard Canyon and Haig Fras marine conservation zones, as part of the CodeMAP (Complex Deep-sea Environments: Mapping habitat heterogeneity As Proxy for biodiversity) project. These data were collected aboard the RRS James Cook cruise JC125 (Chief Scientist Veerle Huvenne), which departed and returned to Southampton from 09 August 2015 to 12 September 2015. The cruise was conducted to carry out habitat mapping work in the Whittard Canyon and Haig Fras to obtain a better insight in the biodiversity patterns, benthic habitat distributions and sediment transportation processes of submarine canyons. The CTD profile data collected supports data from marine geology, ecology, remote sensing and underwater vehicle technology to establish an integrated, statistically robust, and fully 3D methodology to map complex deep-sea habitats. Parameters measured from the CTD profiles include: pressure, depth, temperature, practical salinity, dissolved oxygen, chlorophyll-a fluorescence, transmittance, attenuance and turbidity. Data were collected using a ship deployed stainless steel CTD frame mounted with the following equipment: Sea-Bird 911plus CTD System, Digiquartz pressure sensor, Sea-Bird 3plus premium temperature sensor, Sea-Bird 4C conductivity sensor, Sea-Bird 43 dissolved oxygen sensor, WET Labs ECO BB(RT)D backscattering sensor, Chelsea Technologies Group Aquatracka III fluorometer, Chelsea Technologies Group Alphatracka II transmissometer (25 cm path length). The CTD data were received by the British Oceanographic Data Centre (BODC) having been binned into 2 m depth profiles for the downcast. The data have been processed and quality controlled using in-house BODC procedures and are available to download from the BODC website. Funding was provided by the European Research Council to CodeMAP (Grant No 258482).

This dataset contains particle flux analyses and current measurements collected from sediment traps and associated moored current meter instrumentation. Four McLane sediment traps were deployed in the Iceland Basin (by the Ocean Weather Station India) in a mesoscale array around 60 degrees N 20 degrees W to sample particle flux time series between November 2006 - July 2007 and August 2007 - June 2008. Sediment traps were deployed with Aanderaa RCM8 current meters 15 m below the traps, recording current speed and direction once an hour. The sediment traps were initially deployed during RRS Discovery cruise D312 and recovered on RRS Discovery cruise D321. For the second deployment period the traps were deployed on RRS Discovery cruise D321 and recovered on RRS Discovery cruise D340. The first sediment traps were prepared for analysis by scientists shortly after recovery. The second deployment samples were stored in the dark at 4 degrees Celsius until 2016 and were subsequently analysed. All sediment trap samples are preserved with formalin and hence should not be affected by long time storage. The samples were analysed for mass flux, particulate organic carbon (POC) and nitrogen (PON) flux, calcium carbonate flux, biogenic silica flux (including dissolved contribution for deployment 2), strontium flux (including Acantharian cyst fractions for deployment 1 and 2 and particulate fractions for deployment 2). The samples from the latter part of deployment 2 are thought to have severely under collected and so those data are flagged. The dataset was produced for the purposes of calculating sediment fluxes in the Iceland Basin and was funded by the Natural Environment Research Council (NERC) - Oceans 2025 Programme (Grant number NE/L002531/1).

The dataset comprises chlorophyll-a concentrations from water samples taken during RRS James Clark Ross cruise JR304, from 15/11/2014 - 17/12/2014. The cruise sailed from Punta Arenas, Chile, returning to Stanley, Falkland Islands. Samples were taken during transit to Signy Island (South Orkneys), and then up through the Scotia Sea to BAS survey sites P2 and P3 as well as near South Georgia and in the Western Core Box survey area to the north of the island of South Georgia. 112 samples were collected from the ship’s uncontaminated underway supply, with an intake at approximately 6 m depth, every two hours during transit periods. 103 samples were collected, using a rosette sampler, from the upper 1000m during CTD (conductivity, temperature and depth probe) deployments. Each 300ml sample was filtered through a 0.8μm pore size, 25mm diameter, MPF300 filter, rinsed with milliQ water, placed in an eppendorf tube and stored at -20°C for later analysis. Samples were extracted in 90 % acetone for 22-24 hours at 4°C and measured on a Trilogy Turner Designs 7200 lab fluorometer calibrated with a pure chlorophyll-a standard (Sigma, UK) and set up following the method of Welschmeyer (1994). Data have not been adjusted for blanks. The data set was from the annual Western Core Box Cruise run by British Antarctic Survey (BAS). Data were collected to support the PhD of Anna Belcher and provide seasonal context for the cruise in terms of the primary production in the surface ocean. Chlorophyll samples were taken by Jenny Thomas (BAS), Gabi Stowasser (BAS), Sophie Fielding(BAS), Vicky Peck (BAS), Jess Gardner (University of East Anglia and BAS), Cecilia Liszka (BAS), Manon Duret (National Oceanography Centre, NOC), Anna Belcher (NOC), Anna Mikis (Cardiff University) , Marianne Wootton (Sir Alistair Hardy Foundation for Ocean Science), Sebastien Floter (GEOMAR Kiel). Chlorophyll samples were analysed aboard the R.R.S. James Clark Ross by Manon Duret and Anna Belcher from NOC.

The dataset comprises 92 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, from across the North East Atlantic Ocean (limit 40W) area specifically Rockall Trough, Hatton Bank, Iceland Basin and the Ellett Line. The data were collected during July and August of 2007. 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 National Oceanography Centre, Southampton as part of the Oceans 2025 programme.

The dataset comprises 10 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, and 40 moored CTDs from across the North Atlantic Ocean area specifically the Subtropical North Atlantic, during May and June 2006. 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 National Oceanography Centre, Southampton as part of the Rapid Climate Change Programme.

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.

The Carbon Uptake and Seasonal Traits in Antarctic Remineralisation Depth (CUSTARD) data set comprises hydrographic data, including measurements of temperature, salinity and currents, complemented by bathymetric, meteorological and nutrient data. All the observational data from the project were collected at, and south of, the Ocean Observatories Initiative (OOI) Global Southern Ocean Array, located south-west of Chile. Data collection activities span from November 2018 to January 2020 over 3 cruises (DY096, DY111 and DY112). The main aim of the CUSTARD project is to quantify the seasonal drivers of carbon fluxes in a region of the Southern Ocean upper limb, and estimate how long different quantities of carbon are kept out of the atmosphere based on the water flow routes at the observed remineralisation depths. The lead grant was funded by the NERC grant reference NE/P021247/1 with child grants NE/P021328/1, NE/P021336/1, NE/P021263/1. NE/P021247/1 was held at the National Oceanography Centre, led by Adrian Martin. Child grants were lead by Mark Moore of University of Southampton, Simon Ussher of University of Plymouth and Dorothee Bakker of University of East Anglia respectively.

This dataset comprises 25 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, during 18 August to 5 September 2006 between St Johns, Canada and the southern tip of Greenland. 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 National Oceanography Centre, Southampton as part of the Rapid Climate Change programme.

This dataset comprises 6 hydrographic data profiles, collected by a conductivity-temperature-depth (CTD) sensor package, during November 2005 between 28.9N, 15.9W and 23.8N, 24.1W, approximately. 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 National Oceanography Centre, Southampton as part of the Rapid Climate Change programme.

This dataset contains CTD, chlorophyll, and phytoplankton abundance and biomass data gathered through analysis of discrete water samples collected from multiple sailings of the RV Callista. The data were collected offshore of Falmouth, UK to explore the seasonally stratified waters of the Western English Channel in June and July 2013. Discrete water samples were taken with CTD profiles to examine the phytoplankton communities of subsurface chlorophyll maxima. Phytoplankton taxa/groups were identified, counted, and converted to a measure of biomass to analyse phyotplankton communities to determine if subsurface chlorophyll maximum thin layers (<5m thick) have a distinct phytoplankton community structure to that of broader maxima. The data were collected by Michelle Barnett as part of her PhD study funded by the Graduate School of the National Oceanography Centre, Southampton.