Chironomid Fauna of the Lakes from the Pechora River Basin (Bolshezemelskaia Tundra, Northern Russia): Ecology and Reconstruction of Recent Ecological Changes in the Region
L. B. NAZAROVA1,2,3, E. SELFA4, S. J. BROOKS4, N. SOLOVIEVA5,6, L. S. SYRYKH7,3, V. A. DAUVALTER8
1Potsdam University, 14476, Potsdam-Golm, Karl-Liebknecht str., 24-25
2Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, 14473, Potsdam, Telegrafenberg, A43
3Kazan (Volga) Federal University, 420008, Kazan, Kremlyovskaya str., 18
4The Natural History Museum, SW7 5BD, London, Cromwell Road
5University College London, WC1H 0AP, London, Bedford Way, 26
6Higher Colleges of Technology, PO BOX 7947, Sharjah
7Herzen State Pedagogical University of Russia, 191186, St. Petersburg, emb. Moika, 48
8Institute of the North Industrial Ecology Problems KSC RAS, 184209, Apatity, Akademgorodok, Fersman str., 14А
Keywords: бассейн р. Печора, озера, хирономиды, температура, глубина, континентальность, Российская Арктика, river Pechora basin, lakes, chironomids, temperature, depth, continentality, Russian Arctic
Abstract
We investigated chironomid fauna of surface sediments and a short sediment core (lake Bolshoy Kharbey) from Pechora river basin, Northern Russia. Twenty three investigated lakes have thermokarst, glacial or floodplain origin and are characterised by low mineralization, mostly hydrocarbon-calcium type of water and low concentration of biogenic elements. Most of the lakes have circumneutral pH around >7 and only two lakes are slightly more acidic with pH > 6. In the modern sediments we identified 96 chironomid taxa. Distribution of chironomids in the studied region is driven by continentality, mean T July and рН. Chironomid communities from the core of the B. Kharbey lake demonstrate the highest similarity with the fauna of the deeper lakes of the glacial origin. The glacial lakes have the highest indices of continentality and the lowest winter temperatures within the investigated data set. The chironomid fauna of the glacial lakes is composed of the profundal, oligotrophic and cold-stenotherm taxa. The fauna of the floodplain and thermokarst lakes is more closely related to T July and is composed of littoral and phytophilic taxa of meso- or eutrophic waters and moderate temperature conditions. The fauna of the acidic thermokarst lakes considerably differs from the other lakes. Chironomid communities here are represented by acidophilous taxa, and by the littoral and shallow water acid-tolerant taxa, that apparently, also can tolerate acidification. Studied sediment record covers ca last 250 years. The reconstructed T July during the entire period remain slightly below the modern temperatures. From 1970 reconstructed T July shows steady increase. The reconstructed water depths (WDs) of the lake are higher than today till 1980. The highest WDs are reconstructed for ca 1970. After that the WDs gradually decrease to the modern level. Changes of the WDs are most probably related to changes in the precipitation rate.
|
