Cruise inventory

RRS Charles Darwin CD139

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Charles Darwin (74AB)
Cruise identifierCD139
Cruise period2002-03-01 — 2002-04-15
StatusCompleted
Port of departureDurban, South Africa
Port of returnFremantle, Australia
PurposeResearch
ObjectivesA modern hydrographic section was made across the Indian Ocean at a latitude of about 32° S during a 46-day voyage from Durban to Fremantle aboard RRS Charles Darwin in March-April 2002.
The principal goal of this work was to measure the flows of mass, heat, freshwater, inorganic and organic nutrients, and carbon dioxide across the southern boundary of the Indian Ocean in order to determine the meridional overturning circulation for the Indian Ocean, to define the heat, freshwater, nutrient and carbon transports across 32° S and to produce overall physical and biogeochemical budgets for the Indian Ocean.
A second goal was to examine the climate variability in ocean circulation from comparisons of these new measurements with previous surveys in 1936, 1965, 1987 and 1995. A total of 146 hydrographic stations was made along this transoceanic section.
At each station an instrument package consisting principally of a CTD, 3 Lowered ADCPs and 24 10-litre sampling bottles was lowered from the surface down to the ocean bottom to measure temperature, salinity, oxygen and eastward and northward current profiles throughout the water column. On the way back to the surface, 24 water samples were collected at various depths and these samples were analysed on board ship for salinity and oxygen (to calibrate the continuous electronic profiles), for inorganic nutrients, constituents of the carbon system, and chlorofluorocarbons. Samples were also collected and stored for later, shore-based analyses of helium, tritium, and organic nutrients.
Throughout the cruise velocity data in the upper few hundred metres of the water column were provided by an ADCP mounted in the ship's hull, meteorological variables were monitored and samples of air and rainfall were periodically collected. In addition, 25 Argo floats were launched along the section to provide continuing profiles over the next 5 years.
Chief scientistHarry L Bryden (University of Southampton School of Ocean and Earth Science)
Cruise reportRRS Charles Darwin CD139 cruise report cd139.pdf — access key 'C' (4.12 MB) 
Ocean/sea areas 
GeneralIndian Ocean
Track chartsRRS Charles Darwin CD139 cruise track — cd139trk.pdf (00 MB) 
Measurements 
Physical oceanography 
CTD stationsQuantity: number of stations = 146
Description: CTD, water samplers, oxygen sensors, altimeter, x3 LADCPs
Geochemical tracers (eg freons)Quantity: number of samples = 2100
Description: Water for analysis of Chlorofluorocarbon
Chemical oceanography 
Carbon dioxideQuantity: number of stations = 146
Description: CO2 component analysis (pH, alkalinity, total inorganic carbon)
Other dissolved gasesQuantity: number of stations = 24
Description: Analysis of Helium and Tritium
PhosphateQuantity: number of stations = 146
Description: Skalar San Plus autoanalysis of phosphate, nitrate, nitrite, silicate
NitrateQuantity: number of stations = 146
Description: Skalar San Plus autoanalysis of phosphate, nitrate, nitrite, silicate
NitriteQuantity: number of stations = 146
Description: Skalar San Plus autoanalysis of phosphate, nitrate, nitrite, silicate
SilicateQuantity: number of stations = 146
Description: Skalar San Plus autoanalysis of phosphate, nitrate, nitrite, silicate
AlkalinityQuantity: number of stations = 146
Description: CO2 component analysis (pH, alkalinity, total inorganic carbon)
pHQuantity: number of stations = 146
Description: CO2 component analysis (pH, alkalinity, total inorganic carbon)
Biology and fisheries 
Phytoplankton pigs (eg chlorophyll, fluorescence)Quantity: number of stations = 45
Description: GFF filtered chlorophyll samples for HPLC
Data held at BODC 
Discrete samples 
146  CTD frame plus rosette samplerRadioactivity in the water column
Stable isotope enrichment in the water column
Density of the water column
Chlorophyll pigment concentrations in water bodies
Dissolved noble gas concentration parameters in the water column
Metadata parameters
Silicate concentration parameters in the water column
Vertical spatial coordinates
Alkalinity, acidity and pH of the water column
Other halocarbon concentrations in water bodies
Salinity of the water column
Chlorofluorocarbon concentrations in the water column
Total dissolved inorganic carbon (TCO2) concentration in the water column
Nitrate concentration parameters in the water column
Temperature of the water column
Dissolved oxygen parameters in the water column
Phosphate concentration parameters in the water column