Primary productivity

Determination of primary production using an on deck incubator. Samples were collected from 3 different depths: including the surface, max chl-a and 1% light level (120m)

Phytoplankton pigments (eg chloroph

Collection of phytoplankton pigments for HPLC analysis from 6 depths between the surface and 200m

Dissolved organic matter (inc DOC)

Organic carbon is the main element of dissolved organic matter and marine dissolved organic carbon (DOC) consitutes one of the largest reservoir of reduced carbon on the Earth surface. DOC is operationally defined as the size fraction < 0.7 micrometer. DOC was determined across the entire water column (12 depths) along the cruise transect. Seawater samples were filtered and stored in pre-combusted glass ampoules (at ph 2)

Pelagic bacteria/micro-organisms

Samples for the enumeration of microbes were taken throughout the water column for heterotropic prokaryotes and in the upper 200m for pico-nanophytoplankton (<20 micrometer). Unfiltered seawater samples were fixed with glutaraldehyde (1% final conc), shock-frozen and are stored at -80°C until flow cytometric analyses

Phytoplankton

Nitrogen fixation and net primary production was measured in surface waters at 48 stations using the isotope tagging method (13C/15N). Seawater was taken from Niskin bottles or from the continuous clean pumping system. The samples were inoculated with 15N2 and 13C-HCO3-, incubated for 24 hours in deck incubators and then filtered on GF/F filters. The filters will be analysed by mass spectrometry (EA-IRMS)

Particulate organic matter (inc POC

Collection of filtered seawater for determination of particulate organic matter from 6 depths between the surface and 200m

Biochemical meas. (eg,lipids,amino

Dark community respiration and bacterial respiration (fraction-size <0,8µm) was investigated in constrasting productivity regimes in the Indian sector of the Southern Ocean and in Subtropical waters. Seawater samples for incubation experiments were collected from surface waters at 12 different locations. Samples for cell abundance (phytoplankton, bacteria and HNF), activity (bacteria) and dissolved inorganic carbon were taken in parallel to continious O2 consumption measurements with optodes

Current profiler (eg ADCP)

Oceanic current profiles during stations obtained from L-ADCP instruments mounted on the standard rosette. 1 or 2 profiles by station

Surface corer

A monocorer was attached 20 m below the in situ pumps at several stations, but only six sediment cores were retrieved succesfully. The cores were immediately sliced with plastic plates in 0.2 to 0.5 cm slices and stored frozen at -20°C. The supernatant water was also sampled for measurements of trace element concentrations, including Hg measured on board. The samples will be shipped first to UBO and then to AMU for analyses of trace metals, Hg speciation and stable lead isotope analyses

Multi-beam echosounding

During the exploration of the South West Indian Ridge to detect the possible presence of hydrothermal sources, we previously explored the area with a resolution of 15 m using the Marion Dufresne SMF

Water bottle stations

Niskin bottles

CTD stations

We have carried out 99 deployments of the standard CTD with 22 Niskin cylinders and equipped with 2 LADCP (300 KhZ uplooker and 150 KHZ downlooker and T, S oxygen, fluorimeter, turbidimeter, PAR and altimeter sensors); 40 deployments of the clean CTD with 24 GO-FLO cylinders and equipped with T, S oxygen, fluorimeter, turbidimeter, PAR and altimeter sensors. We have also carried out about ten casts of large-volume water sampling for Be analysis, with dedicated CTD (SBE 19)

Optics (eg underwater light levels)

Measurements of photochemical efficiency by fast repetition rate fluorometry

Oxygen

Sampling in surface waters every 8h to correct the continuous data obtained with an Aanderaa optode. O2 concentrations in the water column were measured using a Sea-Bird oxygen sensor fixed on the standard and clean rosette. Samples were collected at most stations on the standard CTD to correct the sensor data. Ten samples were also collected on two clean casts. Samples were measured onboard within 3 days following the Winkler titration method.

Phosphate

Phosphate concentration

Nitrate

Nitrate concentration

Silicate

Silicic acid concentration

Alkalinity

Surface seawater from the MD pumping system was measured every 25 minutes. Water column samples were also collected from the Niskin bottles at 50 stations. Total CO2 and total alkalinity were measured simultaneously, onboard, following a potentiometric titration method in a closed cell.

Trace elements

Dissolved and particulate trace elements were collected usin the clean CTD and sampled in the clean van. The following dissolved trace elements will be analysed: Fe, Al, Mn, Cu, Co, Zn, Cd, Pb and Mo at LEMAR. For particulate trace elements, the following elements will be analyzed: Fe, Pb, Al, Ti, Mn, Cd, Co, Cd, Zn, Sr, Mo, V, Zr, Y, Ba, P, Cu at LEMAR. Samples for Ga will be analysed by A. Shiller (USA). Samples for cations will be analyzed by Z. Steiner in Kiel (Germany). Ligands by Liverpool

Radioactivity

Seawater samples were collected for the analysis of radium (223Ra, 224Ra, 226Ra, 228Ra), actinium (227Ac), and thorium (228Th). These radionuclides will be used to constrain vertical and horizontal mixing, and to trace water masses. A RaDeCC system (Radium Delayed Coincidence Counter) was used onboard to perform 223Ra and 224Ra analysis. The other radionuclides will be measured onshore by gamma spectrometry and radon emanation

Isotopes

Isotopes of Protactinium, Thorium and Actinium - Samples taken at all long stations and some specific ones (in currents such as Fawn Trough) - Average volumes: 10L per Ac sample, 2L filtered for Pa/Th samples - Pa/Th: Transport tracers and chemical element wells in the ocean - D/P exchange in the water column - Ac: tracer of vertical diffusion in deep waters

Surface measurements underway (T,S)

Sea surface temperature was measured using a SBE38 sensor at the beginning of the pumping system. Sea surface salinity was calculated from conductivity measured using a SBE21 thermosalinograph and in situ temperature from the SBE38 sensor. Surface seawater samples were collected every 8h to measure salinity using a Guidline salinometer

Carbon dioxide

Fugacity of CO2: Underway seasurface measurements using an infra-red analyser

Ammonia

Collection of unfiltered seawater for the determination of Ammonia concentrations between the surface and 300m

Atmospheric chemistry

Aerosol samples were collected on a 24-48 hour integrated basis using high volume aerosol samplers deployed on the flying bridge (above the ship's bridge. Samples were collected for total trace elements, berylium-7, and aerosol mercury and micro-plastics

Suspended matter

Using in-situ pumps, we took 'trace metal and thorium' from the ISP cast: 1) 99 particulate samples on QMA filters (1um mesh size) superimposed on Petex filters of different mesh sizes (5um and 50um) for the analysis of POC, PN, 234Th, delta15N, delta14C, biomarkers, BSi, LSi, POP, Al, Ca, Na and Hg. 2) 85 particulate samples on Supor filters (0.8um mesh) for the analysis of trace metal concentrations, Zn, Ni and Si isotopes, proteins, etc.

Trace metals

On board measurements of total mercury and dissolved gaseous mercury of seawater samples collected by trace metal clean rosette and GeoFish. Measurements were done by oxide-reduction of mercury and subsequently analysis by purge and trap cold vapor atomic fluorescence spectrometry