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RRS James Cook JC191

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS James Cook (740H)
Cruise identifierJC191
Cruise period2020-01-19 — 2020-03-01
StatusCompleted
Port of departureFort Lauderdale, United States
Port of returnSanta Cruz de Tenerife, Spain
PurposeResearch
ObjectivesA hydrographic section across the North Atlantic Ocean at a nominal latitude of 24°N was occupied by the RRS James Cook (cruise identifier: JC191) from 19 January to 1 March, 2020. The ship departed from Port Everglades, USA, completing a total of 135 CTD stations over the Florida Straits, the western basin, Mid-Atlantic Ridge, and eastern basin, before ending the cruise in Santa Cruz de Tenerife, Spain. The main objectives of the JC191 research expedition was to collect physical-, chemical-, and biological-ocean data with the purpose of estimating heat, freshwater and carbon budgets on low frequency time scales. All CTD stations had measurements from a CTD rosette equipped with temperature, conductivity, pressure, oxygen sensors, in addition to water captured from 24 niskin bottles fired at varying intervals throughout the full depth water column. The water from the niskin bottles was analysed for dissolved oxygen, carbon (DIC/TA), nutrients, and conductivity. Water for methane (CH4), C14, C13, and pigments (filtered) was collected for onshore analysis. The CTD rosette was also equipped with 2 RBR loggers measuring conductivity, temperature and pressure (up to 6,000m), and a lowered Acoustic Doppler Current Profiler (LADCP) making full depth velocity measurements. The 135 CTD stations include 2 carbon blank stations, and 2 bulk water stations for incubations. In addition to the CTD stations, the RRS James Cook has an underway system, which includes an intake for surface water to be pumped into the water bottle annex and the deck lab; two vessel mounted ADCPs (VMADCPs). A thermosalinograph and a fluorometer, installed in the water bottle annex, continually recorded conductivity, temperature and fluorescence. Water from the CTD was collected to calibrate the ship's underway TSG. The VMADCPs, 75Hz and 150HZ, mounted on the drop keel record ocean velocities in roughly the top 300- and 600-m, respectively. Surface carbon and methane measurements were also recorded from the underway systems, and surface meteorological variables were monitored via the meteorological sampling system and the pumped water underway system. Finally bathymetric data were recorded an EA640 echosounder and a Kongsberg EM122 multibeam, both of which are mounted on the ship's hull. Last, 5 Deep Apex Argo floats measuring conductivity, temperature, pressure and oxygen (except for one float not equipped with an optode) were deployed in the western basin.
Chief scientistAlejandra Sanchez-Franks (National Oceanography Centre, Southampton)
Cruise reportRRS James Cook JC191 cruise report jc191.pdf (33.45 MB) 
Ocean/sea areas 
GeneralNorth Atlantic Ocean
Measurements 
Physical oceanography 
Surface measurements underway (T,S)Quantity: activity duration in days = 43
Description: Underway pumped seawater physical parameters. Parameters: salinity, temperature, beam transmission, fluorescence
Water bottle stationsQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to determine carbon parameters (DIC, TA)
Water bottle stationsQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to determine inorganic nutrient concentration. Analysed with segmented flow autoanalyser and colourimetric detection.
Water bottle stationsQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to calibrate CTD conductivity sensor. Analysed using an autosalinometer standardized with a sea water standard.
Water bottle stationsQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to calibrate CTD oxygen sensor. Analysed using a dissolved oxygen analyser with automatic end-point detection.
CTD stationsQuantity: number of stations = 135
Description: SeaBird 9/11. 234 CTD casts total. Parameters: temperature, salinity, pressure, oxygen, fluorescence, beam transmission, turbidity; altimeter, water velocities
Current profiler (eg ADCP)Quantity: number of stations = 135
Description: LADCP
Current profiler (eg ADCP)Quantity: activity duration in days = 43
Description: 150 and 75kHz vessel-mounted ADCP surveys
Chemical oceanography 
OxygenQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to calibrate CTD oxygen sensor. Analysed using a dissolved oxygen analyser with automatic end-point detection.
Carbon dioxideQuantity: activity duration in days = 43
Description: Underway pCO2
Carbon dioxideQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to determine carbon parameters (DIC, TA)
Other dissolved gasesQuantity: number of stations = 70
Description: Discrete water samples collected for analysis dissolved methane for shoreside analysis
PhosphateQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to determine inorganic nutrient concentration. Analysed with segmented flow autoanalyser and colourimetric detection.
NitrateQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to determine inorganic nutrient concentration. Analysed with segmented flow autoanalyser and colourimetric detection.
NitriteQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to determine inorganic nutrient concentration. Analysed with segmented flow autoanalyser and colourimetric detection.
SilicateQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to determine inorganic nutrient concentration. Analysed with segmented flow autoanalyser and colourimetric detection.
AlkalinityQuantity: number of stations = 135
Description: Discrete water samples collected from CTD bottles to determine carbon parameters (DIC, TA)
IsotopesQuantity: number of stations = 19
Description: Carbon isoptopes 14C for shoreside analysis
Biology and fisheries 
Phytoplankton pigs (eg chlorophyll, fluorescence)Quantity: number of stations = 47
Description: Discrete water samples collected for particulate and dissolved organic carbon (POC/DOC), Nitrogen (PON/DON), phosphurus (POP/DOP) and chlorophyll a.
Particulate organic matter (inc POC, PON)Quantity: number of stations = 47
Description: Discrete water samples collected for particulate and dissolved organic carbon (POC/DOC), Nitrogen (PON/DON), phosphurus (POP/DOP) and chlorophyll a.
Dissolved organic matter (inc DOC)Quantity: number of stations = 47
Description: Discrete water samples collected for particulate and dissolved organic carbon (POC/DOC), Nitrogen (PON/DON), phosphurus (POP/DOP) and chlorophyll a.
Meteorology 
Routine standard measurementsQuantity: activity duration in days = 43
Description: Underway Meteorology. Parameters: air temperature, air humidity, wind speed, wind direction, atmospheric pressure, TIR, PAR
Moorings, landers, buoys 
Physical oceanography 
Neutrally buoyant floats
Neutrally buoyant floats
Neutrally buoyant floats
Neutrally buoyant floats
Neutrally buoyant floats