Some time for water sampling. I have been lucky to get some water from the Rosette-sampler which is a set of many bottles in a ring which collects water at different pre-set depths as the samples descends down by a wire through the water. We can see the different water masses which the Rosette-samples passes through since there is a CTD (conductivity, Temperature, Depth) monitor attached to the Rosette (it sits in the middle of the ring of bottles) and since the surface upper mixed water (about 30-100m) have a different conductivity and temperature than the water masses below we can collect water samples from various water masses that carry different chemical and biological signals which we wants to quantify.

Collection of small volume seawater samples:

Compared to ⁹⁹Tc where large volumes usually are required we only need some 1-5 litres for iodine isotopes (¹²⁷I and ¹²⁹I), the 127I only needs a fraction of a millilitre but the artificial 129I is very rare. There is probably only about one ¹²⁹I atom for every 100 billion ¹²⁷I atoms in the water of the Antarctic circumpolar current so we need both to isolate iodine from some litres of water and to use more sophisticated equipment than is used for stable (127I). The equipment used is the same as for carbon-14 determination, Accelerator Mass Spectrometry (AMS).