色素法による湖水の還元層の研究

抄録

As is well known some of the eutrophic lakes develop anerobic layer during the summer. In the present study this layer was studied on six Japanese lakes making use of the idea of redox potential. For measuring the gradients of reduction intensity in the anerobic layer leucobase of indigo carmine was used, with the result that this method conveniently enalbes the determination of the vertical distribution of reduction power in the anerobic layer. The data obtained showed that the reduction power of water rapidly increases at the upper lmeter of anerobic layer, and from this downwards it increases gradually. It was also remarkable that the reduction of indigo carmine was observed in the presence of a trace of molecular oxygen. This may probably be due to the presence of some reducing agents such as Fe••, Ma••, SH₂, which may reduce indigo carmine before oxidizing itself by taking molecular oxygen.