Effects of Thermal Pollution on the Black Flies of the Irtysh River in Kazakhstan

Abstract

The article describes the impact of thermal pollution of water of the river Irtysh, in its middle reaches, by water used in the technological process of Aksu SRPP Teplaya tributary (Pavlodar region, Republic of Kazakhstan). The temperature of the water coming out of the Aksu SRPP is 4-6 degrees higher which accounts for 18 degrees in mid-May to 23 degrees in mid-June in 2012 and 2015 than in the main channel, which affects the ecology and species diversity of representatives of the family Simulidae (blackflies), order Diptera, whose larvae develop in the waters of the river. Increased water temperature in the Teplaya tributary affects the biology of Simuliidae, reducing the development time of their larval and adult flight summer phases. Adult imago simulid flight in the Teplaya tributary is 36-48 h ahead of adults in the main channel. The sensitive blood-sucking activity of adult Simuliidae is felt by the population from the second decade of May to the end of June. At the same time, the aggressiveness of the adult hatch from the Teplaya tributary was felt on May 13-14 during the observation years, whereas that from the main channel occurred on May 15-17. The article describes the ecological characteristics of the river section where observations were made. The observation orbit includes a section of the Irtysh River with a length of about 40 km (20 km above and below the Aksu SRPP), where there is a noticeable difference in water temperature before the SRPP and after draining the process water. The reasons for changes in biodiversity of Simuliidae and peculiarities of habitats of larval forms of Simuliidae in conditions of "regulated" flooding are discussed.