temperature

The effect of temperature, isotopic composition of water and ethanol on the tautomeric equilib- rium of two phenylazonaphtholes that differ by sulphonic group in benzene ring was investigated spectrophotometrically. It was established that enhancement of water structure under decrease of temperature or change of common water to heavy one shifts the azoquinonhydrazone tautomeric equilibrium to more polar hydrazone tautomer.

In the rivers of the Yenisei basin, benthic invertebrates play a major role in feeding most valuable Siberian fish species. This report presents advanced material on zoobenthos of the river Kan (one of the major tributaries of the Yenisei in its middle course). Litho-psammo-rheophilic biocenosis of benthic invertebrates was the most developed, 99 species and forms were recorded there. The total number of zoobenthos was formed from mayflies, caddisflies and chironomids; biomass – from caddisflies and mayflies.