Фитопланктон горных озёр Прибайкалья и Забайкалья

Abstract

A brief description of phytoplankton in the alpine lakes located westward and eastward Lake Baikal within the Baikalian rift zone is given. These lakes are mostly virgin so they could be used as a pure background with almost absence of the anthropogenic activity. In each lake, its peculiar algoflora was formed reflecting climatic, landscape, lake's basin shape, and drainage area conditions. The phytoplankton were mainly consisted of green, chrysophyte, and diatom algae. The species and subspecies diversity was found in a low number of genera not in all one. The baikalian endemic diatoms A. baicalensis (K. Meyer) Sim., Сyclotella baicalensis, C. minuta, Stephanodiscus meyeri, and spore-forming A. islandica (this form of the alga is known to dwell in the lake Khanka and the river Amur, Far East, only), as well as dinoflagellate Gymnodinium baicalense var. minor, have been found there. In most lakes, the relict alga Pliocaenicus costatus, wide-spread in ancient times from Europe to the Kamchatka peninsula, has been observed also. Sets of the dominant species were monodominant. On number and biomass, diatoms were dominant in 59% of the lakes, bluegreen algae and chrysophytes in 15%, green algae in 9%, and dinophytes in 2%. The biomasses varied mainly 50 to 100 mg·m-3, sometimes during the open water period 300 to 600 мгꞏм-3 and 800 мгꞏм-3 in shallows. The phytoplankton exhibited three peaks in their seasonal development and autumn one was maximal. The composition and development of the phytoplankton in the alpine lakes within the Baikalian rift zone testify to their virgin states without acidification.