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RRS James Cook JC159

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS James Cook (740H)
Cruise identifierJC159
Cruise period2018-02-28 — 2018-04-10
StatusCompleted
Port of departureRio de Janeiro, Brazil
Port of returnCape Town, South Africa
PurposeResearch
ObjectivesA Hydrographic section was occupied at a nominal latitude of 24°S in the Atlantic Ocean during March and April 2018 on Cruise JC159 of RRS James Cook. The primary objective of this cruise was to measure ocean physical, chemical and biological parameters in order to establish regional budgets of heat, freshwater and carbon, and to infer decadal variability. In addition, 371 Niskin Bottles were sampled for microplastics, reflecting increasing awareness of plastics pollution in the oceans.

A total of 121 CTD/LADCP stations were conducted, including one test station and two CFC bottle blank stations. In addition to temperature, salinity and oxygen profiles from the sensors on the CTD package, water samples from a 24 x 20 litre rosette were analysed for the following parameters at all stations: salinity; dissolved oxygen; inorganic nutrients; alkalinity and dissolved inorganic carbon; CFCs. Samples were collected for shore analysis for oxygen and carbon isotopes (del-18O, del13C and del-14C). Samples were collected and filtered for pigments (shore analysis) at 44 stations and for microplastics at 45 stations. 8 Argo floats were deployed, including two Bio-PROVOR floats and 2 Deep ARVORs.

In addition, samples were collected from the ships’ underway system to calibrate and compliment the data continually collected by the TSG (thermosalinograph). Full depth velocity measurements were made at every station by LADCP (Lowered Acoustic Doppler Current Profiler) mounted on the frame of the rosette. Throughout the cruise, velocity data in the upper few hundred metres of the water column were collected by the ship’s VMADCP (Vessel Mounted Acoustic Doppler Current Profiler) transducers (75Hz and 150Hz) mounted on one of the two drop keels. Meteorological variables were monitored using the onboard surface water and meteorological sampling system (SURFMET). Bathymetric data were collected using the Kongsberg EM122 multibeam system and the EA640 echo sounder.
Chief scientistBrian A King (National Oceanography Centre, Southampton)
ProjectOcean Regulation of Climate by Heat and Carbon Sequestration and Transports (ORCHESTRA)
Cruise reportRRS James Cook JC159 cruise report jc159.pdf (34.50 MB) 
Ocean/sea areas 
GeneralSouth Atlantic Ocean
Track chartsRRS James Cook JC159 cruise track — jc159trk.pdf (1.18 MB) 
Measurements 
Physical oceanography 
CTD stationsQuantity: number of deployments = 125
Description: CTD casts, using Sea-Bird Electronics 9+ with dual temperature/conductivity sensors, dissolved oxygen, transmissometer, fluorometer, PAR sensor. Downward- and upward-looking 300-kHz lowered ADCPs were used on all 60 stations
Subsurface temperature and salinity measurementsQuantity: activity duration in days = 42
Description: Routine underway measurements of temperature, salinity, transparency, and chlorophyll fluorescence
Current profiler (eg ADCP)Quantity: number of deployments = 125
Description: CTD casts, using Sea-Bird Electronics 9+ with dual temperature/conductivity sensors, dissolved oxygen, transmissometer, fluorometer, PAR sensor. Downward- and upward-looking 300-kHz lowered ADCPs
Current profiler (eg ADCP)Quantity: activity duration in days = 42
Description: Current profiles from vessel-mounted ADCP
Neutrally buoyant floatsQuantity: number of deployments = 8
Description: Argo floats deployments
Other physical oceanographic measurementsQuantity: number of samples = 197
Description: Samples collected from non-toxic underway supply for salinity calibration
Chemical oceanography 
OxygenQuantity: number of samples = 310
Description: Samples for dissolved Oxygen analysis used to calibrate the CTD
Other dissolved gasesQuantity: number of samples = 100
Description: Samples collected for CFC and SF6 analysis
PhosphateQuantity: number of samples = 2616
Description: Samples collected for macro-nutrient analysis from 115 hydrographic stations
NitrateQuantity: number of samples = 2616
Description: Samples collected for macro-nutrient analysis from 115 hydrographic stations
NitriteQuantity: number of samples = 2616
Description: Samples collected for macro-nutrient analysis from 115 hydrographic stations
SilicateQuantity: number of samples = 2616
Description: Samples collected for macro-nutrient analysis from 115 hydrographic stations
AlkalinityQuantity: number of samples = 3035
Description: Samples collected for DIC and TA analysis
RadioactivityQuantity: number of deployments = 124
Description: Samples collected for Radiocarbon analysis
IsotopesQuantity: number of samples = 2784
Description: Samples collected for 18O and 13C analysis
Other chemical oceanographic measurementsQuantity: number of samples = 3035
Description: Samples collected for DIC and TA analysis
Contamination 
Other contaminant measurementsQuantity: number of samples = 45
Description: Samples collected from CTD bottles and non-toxic underway flow for microplastics determination
Biology and fisheries 
PhytoplanktonQuantity: number of deployments = 44
Description: Samples collected for Phytoplankton identification and biomass determination
Data held at BODC Get data
Discrete samples 
123  CTD frame plus rosette sampler