RRS Discovery DY031
Cruise summary report
| Cruise Info. | |||||
| Ship name (ship code) | RRS Discovery (74EQ) | ||||
| Cruise identifier | DY031 | ||||
| Cruise period | 2015-05-29 — 2015-06-17 | ||||
| Status | Completed | ||||
| Port of departure | Southampton, United Kingdom | ||||
| Port of return | Liverpool, United Kingdom | ||||
| Purpose | Research | ||||
| Objectives | Objectives
- Complete the annual Extended Ellett Line CTD section - Collect water samples for measuring biogeochemical properties including dissolved oxygen, nutrients, carbon and trace metals. - Collect underway measurements of surface currents, surface temperature and salinity, bathymetry, surface meteorology. - Complete epibenthic sled tows at a deep location in the central Rockall Trough. - Launch a seaglider for a related research programme (near Rockall) which will stay in UK or international waters. - Launch a second seaglider for a related research programme (near Iceland) which will operate in Iceland and Greenland waters. - Deploy 2 Met Office Argo floats along the CTD section The Extended Ellett Line is a hydrographic section between Iceland and Scotland that is occupied annually by scientists from the National Oceanography Centre (NOC) and the Scottish Association for Marine Science (SAMS), UK. The measurement programme began as a seasonally-occupied hydrographic section in the Rockall Trough in 1975, building on early surface observations made underway from ocean weather ships. In 1996 the section was extended to Iceland, sampling three basins: the Rockall Trough, the Hatton-Rockall Basin and the Iceland Basin. These three basins form the main routes though which warm saline Atlantic water flows northwards into the Nordic Seas and Arctic Ocean. The section crosses the eastern North Atlantic subpolar gyre; as well as the net northward flow there is a large recirculation of the upper layers as part of the wind-driven gyre. During its passage through the region, the warm saline water is subjected to significant modification by exchange of heat and freshwater with the atmosphere. The two deep basins (Rockall Trough and Iceland Basin) contain southward flowing dense northern overflow waters, and Labrador Sea Water in the intermediate layers. | ||||
| Chief scientist | N Penny Holliday (National Oceanography Centre, Southampton) | ||||
| Project | Extended Ellet line | ||||
| Coordinating body | Natural Environment Research Council (NERC) | ||||
| Cruise report |  (2.58 MB) | ||||
| Ocean/sea areas | |||||
| General | North East Atlantic Ocean (limit 40W) | ||||
| Specific | Rockall Trough, Hatton-Rockall Basin, Iceland Basin. | ||||
| Track charts | (0.12 MB) | ||||
| Measurements | |||||
| Physical oceanography | |||||
| Surface measurements underway (T,S) | Quantity: number of stations = 81 Description: Discrete salinity samples taken from underway system intake. Measured on board. | ||||
| Surface measurements underway (T,S) | Quantity: activity duration in days = 20 Description: Underway thermosalinograph measurements of sea surface temperature, conductivity, transmittance and fluorescence. | ||||
| Water bottle stations | Quantity: number of stations = 82 Description: Discrete salinity samples from CTD bottles. Measured on board. | ||||
| CTD stations | Quantity: number of stations = 85 Description: Standard SBE9/11+ CTD package measuring conductivity, temperature, transmittance, turbidity, fluorescence and oxygen. | ||||
| Transparency (eg transmissometer) | Quantity: number of stations = 85 Description: Standard SBE9/11+ CTD package measuring conductivity, temperature, transmittance, turbidity, fluorescence and oxygen. | ||||
| Transparency (eg transmissometer) | Quantity: activity duration in days = 20 Description: Underway thermosalinograph measurements of sea surface temperature, conductivity, transmittance and fluorescence. | ||||
| Current profiler (eg ADCP) | Quantity: activity duration in days = 15 Description: Underway ADCP measurements, 75 kHz system. | ||||
| Current profiler (eg ADCP) | Quantity: activity duration in days = 15 Description: Underway ADCP measurements, 150 kHz system. | ||||
| Current profiler (eg ADCP) | Quantity: number of stations = 84 Description: Downward looking lowered ADCP measurements, 300kHz system. | ||||
| Chemical oceanography | |||||
| Oxygen | Quantity: number of stations = 82 Description: Discrete dissolved oxygen samples taken from CTD bottles. Measured on board. | ||||
| Oxygen | Quantity: number of stations = 85 Description: Standard SBE9/11+ CTD package measuring conductivity, temperature, transmittance, turbidity, fluorescence and oxygen. | ||||
| Oxygen | Quantity: number of stations = 40 Description: Discrete dissolved inorganic carbon (DIC) and Total Alkalinity (TA) samples taken from underway system intake. Measured on board. | ||||
| Phosphate | Quantity: number of stations = 81 Description: Discrete nutrient samples taken from CTD bottles. Measured on board. | ||||
| Total - P | Quantity: number of stations = 81 Description: Discrete nutrient samples taken from CTD bottles. Measured on board. | ||||
| Nitrate | Quantity: number of stations = 81 Description: Discrete nutrient samples taken from CTD bottles. Measured on board. | ||||
| Nitrite | Quantity: number of stations = 81 Description: Discrete nutrient samples taken from CTD bottles. Measured on board. | ||||
| Total - N | Quantity: number of stations = 81 Description: Discrete nutrient samples taken from CTD bottles. Measured on board. | ||||
| Silicate | Quantity: number of stations = 81 Description: Discrete nutrient samples taken from CTD bottles. Measured on board. | ||||
| Alkalinity | Quantity: number of stations = 80 Description: Discrete Dissolved Inorganic Carbon (DIC) and Total Alkalinity (TA) from CTD bottles. Measured on board. | ||||
| Isotopes | Quantity: number of stations = 10 Description: Discrete oxygen isotope samples from CTD bottles | ||||
| Other chemical oceanographic measurements | Quantity: number of stations = 80 Description: Discrete Dissolved Inorganic Carbon (DIC) and Total Alkalinity (TA) from CTD bottles. Measured on board. | ||||
| Contamination | |||||
| Trace metals | Quantity: number of stations = 10 Description: Discrete trace metal measurements from CTD bottles. Measured on board. | ||||
| Biology and fisheries | |||||
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: number of stations = 85 Description: Standard SBE9/11+ CTD package measuring conductivity, temperature, transmittance, turbidity, fluorescence and oxygen. | ||||
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: number of stations = 42 Description: Discrete chlorophyll samples taken from CTD bottles. Measured on board. | ||||
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: activity duration in days = 20 Description: Underway thermosalinograph measurements of sea surface temperature, conductivity, transmittance and fluorescence. | ||||
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: number of stations = 11 Description: Discrete phytoplankton samples from CTD bottles. | ||||
| Other biological/fisheries measurement | Quantity: number of stations = 5 Description: Epibenthic sled tows. | ||||
| Meteorology | |||||
| Routine standard measurements | Quantity: activity duration in days = 20 Description: Underway meteorology measurements of radiation, air temperature, wind speed and direction, relative humidity and air pressure. | ||||
| Moorings, landers, buoys | |||||
| Physical oceanography | |||||
| Neutrally buoyant floats | 60° 30' 0" N 20° 0' 0" W — Argo float SN 7208 | ||||
| Neutrally buoyant floats | 59° 19' 59" N 18° 10' 0" W — Argo float SN 7207 | ||||
| Other physical oceanographic measurements | 57° 57' 0" N 14° 34' 59" W — Seaglider SG603 | ||||
| Other physical oceanographic measurements | 62° 40' 0" N 19° 40' 0" W — Seaglider SG606 | ||||
| Data held at BODC | Get data | ||||
| Series/Profiles | |||||
| 86 Acoustic doppler current profiler | Reference numbers Horizontal spatial co-ordinates Date and time Vertical spatial coordinates Horizontal platform movement Horizontal velocity of the water column (currents) Reference numbers Horizontal spatial co-ordinates Date and time Vertical spatial coordinates Horizontal platform movement Horizontal velocity of the water column (currents)
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| 158 Bottle station | Reference numbers Vertical spatial coordinates Dissolved oxygen parameters in the water column Phosphate concentration parameters in the water column Silicate concentration parameters in the water column Metadata parameters Nitrate concentration parameters in the water column Quality control flags Reference numbers Vertical spatial coordinates Dissolved oxygen parameters in the water column Phosphate concentration parameters in the water column Silicate concentration parameters in the water column Metadata parameters Nitrate concentration parameters in the water column Quality control flags
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| 85 CTD/STD cast | Reference numbers Transmittance and attenuance of the water column Vertical spatial coordinates Optical backscatter Dissolved oxygen parameters in the water column Temperature of the water column Salinity of the water column Density of the water column Electrical conductivity of the water column Chlorophyll pigment concentrations in water bodies Reference numbers Transmittance and attenuance of the water column Vertical spatial coordinates Optical backscatter Dissolved oxygen parameters in the water column Temperature of the water column Salinity of the water column Density of the water column Electrical conductivity of the water column Chlorophyll pigment concentrations in water bodies
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| 1 Pumped water sample | Horizontal spatial co-ordinates Total dissolved inorganic carbon (TCO2) concentration in the water column Date and time Alkalinity, acidity and pH of the water column Horizontal spatial co-ordinates Total dissolved inorganic carbon (TCO2) concentration in the water column Date and time Alkalinity, acidity and pH of the water column
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| Discrete samples | |||||
| 85 CTD frame plus rosette sampler | Total dissolved inorganic carbon (TCO2) concentration in the water column Phosphate concentration parameters in the water column Salinity of the water column Dissolved oxygen parameters in the water column Silicate concentration parameters in the water column Nitrate concentration parameters in the water column Metadata parameters Alkalinity, acidity and pH of the water column | ||||
| 5 Epibenthic Sledge | |||||
| 147 Sample taken from ship's non-toxic supply | Total dissolved inorganic carbon (TCO2) concentration in the water column Alkalinity, acidity and pH of the water column |
