Expedice 2015

Strange Water Values and Red Plants in Ironfree Water

Close to our camp was the water hole Glen Helen. On the walk to the actual water hole we saw crystallised salt in the riverbed where water was once flowing. An analysis of the water showed a high salinity with a conductance of 5230 microsiemens/cm, a general hardness of over 36 and a carbonate hardness of 11 °dKH. These values made us curious, so we also determined the potassium content, which exceeded 15 mg/l. Due to the high salt content we unpacked the saltwater tests and determined the calcium and magnesium levels with these tests, which in normal freshwater wouldn’t indicate anything because of the too low values. The results were a surprise. The Ca content and the KG content were below 180 mg/l. Since the KH had only 11 °dKH, Ca, K, and MG seemed to be bound to other partners than to carbonates. Which ones these were, exactly, we weren’t able to measure. Really astonishing was the fact that a Cryptocoryne species with wonderful red leaf colouring was flourishing in water with no measurable iron. The low water temperature of only 22.3 °C indicated that an underground source was feeding the water hole here as well. The next morning we took the opportunity to view the region from a helicopter. Here it became apparent that the original waters were drying out more and more, but their salt deposits were still clearly visible, even from a great height.