Nutrients in ice. Some data from a highmountain lake

Summary

In connection with hydrographical investigations in a high mountain lake the ice was also analysed. These analyses indicated relatively high content of nutrients (PO₄, NO₃ + NO₂, and NH₄) in the ice, and the most surprising feature was the content of PO₄ and its irregular, vertical as well as horizontal, distribution.

Freezing experiments in the laboratory showed that waters from the lake increased in PO₄ content after completely freezing in a sample bottle. These experiments indicate that PO₄ can be released from some organic substances during the freezing process, and that this phenomenon also applies to the ice frozen on the lake.

On the basis of hydrographical research just after the spring thaw, the relatively great amount of PO₄ in the ice of the lake (and probably also in the ice of the drainage area) seems to have a great influence on the PO₄ content of the water masses.