‘Ultra Low Level’ Tritium Measurements

To demonstrate the capability of the system a tritium profile from the Weddell Sea (Antarctica) is shown in Fig. 21. These measurements clearly show that in the southern hemisphere the structure of the tritium profiles can be only resolved by measurement of tritium via 3He ingrowth. The good agreement of the duplicate samples is evidence for the overall reproducibility of the measurements. The nonzero values in the tritium minimum are expected from the turnover times of the water masses of the Weddell Sea and can not be interpreted as an offset in our measurements.