Yenisei River
Yenisei River in Russia viewed from satellite. Source: NASA
The Yenisei River rises in Mongolia and discharges to the Kara Sea. Also known by the name Yenisei-Angara River System, the catchment area ranks the Yenisei Basin as the fifth largest drainage area on Earth, at 2,580,000 square kilometres. Under a strong continental climatic influence, the basin is subject to very wide seasonal temperature variations, with some locations such as Krasnoyarsk subject to summer temperatures regularly exceeding 30 degrees Celsius and winter temperatures typically below minus 30 degrees Celsius; moreover, northern portions of the catchment attain winter extremes below 60 degrees Celsius, while southern reaches are frequently above 40 degrees Celsius in summer.
Yenisei River basin, Siberia. Source: K.Musser
Since the industrialization of the region by the communist Soviet government beginning in the 1950s the Yenisei and other major Siberian rivers have become the most polluted of the Arctic discharging rivers.
Contents
Geological history
During the most recent Ice Age during the Weichselian Glaciation, ice sheeting prevented the current discharge of the Yenisei to the Kara Sea, through formation of the Barents-Kara Ice Sheet. Consequently during the recent peak of glacial advance around 80,000 years ago, the Yenisei flowed southward to contribute to the vast West Siberian Glacial Lake.
Hydrology
Conventionally the Yenisei is divided into three principal reaches.
- The upper Yenisei consists of the portion of the river extending from the headwaters to the Tuba River.
- The middle Yenisei runs from the Tuba confluence to the inflow from the Angara River, the uppermost reach of which feeds Lake Baikal.
- The lower Yenisei extends from the Angara confluence to the discharge at the Kara Sea.
The middle Yenisei has been stripped of most of its natural environment, through construction of the massive Krasnoyarsk hydroelectric power plant in 1967 and extensive concomitant industrial and miltary development during the communist era leading to large scale water pollution.
Below Krasnoyarsk the steep Yeniseikiy Kryazh Mountains are a dominant feature of the right bank all the way to the confluence with the Angara. Further downstream beyond the inflow with the Nizhnyaya Tunguska River, the Yenisei width ranges from two to five kilometres, then forming a braided channel form.
The Yenisei has an average water depth of 14 metres over its entire course; in winter, the totality of the surface of the northern reaches are completely frozen for many months. Flow in the Yenisei River is subject to flooding in the spring and summer, propelled by high seasonal rainfall and snowmelt. Sediment load of the river temporally tracks high flows, such that the greatest silt loads are carried in the spring and early summer; however, most of the sediment deposition occurs in the lower.
The Siberian Arctic rivers are the most polluted Arctic inflows, discharging over one hundred times the pesticide and herbicide loads of North American and Scandinavian rivers. This trend was initiated with the communist regime and its program of centrally planned large scale military and industrial use of the Yenisei River.
Considerable heavy metal discharges occur from the Yenisei to the Kara Sea, notably copper and nickel, whose concentrations can be traced back to peaks during the 1970s and 1980s, when the Soviet Government utilized many industrial sites along the Yenisei for military and industrial development during the Cold War. Further legacy of this Soviet era is considerable radioactive sediment at the bottom of the middle and lower Yenisei.
Aquatic biota
Siberian sturgeons are native to the Yenisei. Source: Citron/Creative Commons Notable native demersal fish species in the Yenisei River include the 200 centimeter (cm) long Siberian sturgeon (Acipenser baerii), the 85 cm tench (Tinca tinca), the 125 cm sterlet sturgeon (Acipenser ruthenus) and the 35 cm Arctic flounder (Liopsetta glacialis).
Example native benthopelagic fish species in the Yenisei Basin are the 19 cm Siberian gudgeon (Gobio cynocephalus) and the 14 cm stone sculpin (Paracottus knerii).
More than 100 taxa of benthic invertebrates have been identified in the stretch of the Yenisei between the mouth of the Angara and the Krasnoyarsk hydroelectric plant; moreover, there is evidence of invasion of Lake Baikal benthic inverebrates downriver reaching as far as Krasnoyarsk, expanding their historic range and leading to ecological disruption in the Yenisei. Notably, the amphipods Gmeloides fasciatus and Philolimnogammarus viridis have migrated downriver and have become dominant benthic alien species not only in the mainstem Yenisei, but also in certain tributaries such as the Kan River.
Terrestrial ecoregions
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East of the mouth of the Yenisei is located the Taimyr central Siberian tundra. This ecoregion has frozen ground for the majority of the year. In the northern reach on the Taimyr Peninsula is the only location outside of North America where muskox are found; this mammal was extirpated in Asia around the time of Christ, but has recently been successfully reintroduced.
West of the mouth of the Yenisei is situated the Yamai-Gydan tundra. This tundra ecoregion of western Siberian tundra extends to the Ural Mountains at the west. Mapped boundaries of the Yamai-Gydan tundra correspond to the montane and lowland tundra of the Yamalagydanskaya vegetation province.
South of the Yamai-Gydan tundra ecoregion lies a vast coniferousforest ecoregion known as the West Siberian taiga, that extends from the Urals to the Yenisei River. In general, the ecoregion boundaries correspond to Kurnaev’s taiga in the Western Siberian province from the Ural Mountains to the Yenisei River. However, Kurnaev’s taiga east of the Yenisei River was attached to the East Siberian taiga ecoregion, since the Yenisei is considered a significant biogeographic boundary in most sources. This ecoregion contains both boreal forests and Arctic taiga.
East of the Yenisei the companion ecoregion to the West Siberian taiga is the East Siberian taiga ecoregion, which is one of the most expansive on Earth. The East Siberian taiga spans more than twenty latitudinal degrees and over fifty longitudinal degrees, ranging as far east as the Lena River. Larch forests are dominant due to their ability to tolerate the broad temperature extremes. As is the case of the West Siberian taiga, the east counterpart is relatively stable and intact, largely due to the sparse population of the region.
There are many endemics at the species and genus levels in the East Siberian taiga. Central Yakutia is considered one of the endemism centers in Siberia. The flora of eastern Siberia manifest over 2300 species. Flora of vascular plants of Central Siberian plateau include 1010 species. More than 650 species have been found in Olekminskij Zapovednik alone. Endemics of Cental Yakutia include: Adenophora jacutica and Polygonum amgense. Other eastern Siberia endemics found here are: Megadenia bardunovii, Oxytropis calva, O. leucantha, Viola alexandroviana, Senecio lenensis, Salix saposhnikovii, Juncus longirostris, Gastrolychnis angustifolia ssp. tenella, Caltha serotina,Papaver variegatum, Draba sambykii, Thymus evenkiensis, Potentilla jacutica, Artemisia czekanowskiana. Endangered plant species include: Cypripedium macranthon, Calypso bulbosa, Orchis militaris and Cotoneaster lucidus. Avian species include the hooded crow (corvus cornix), Arctic warbler (Phylloscopus borealis) and the blackheaded greenfinch (Carduelis ambigua).
Prehistory
Paleolithic peoples inhabited the banks of the Yenisei near present day Krasnoyarsk, leaving archaeological finds of Mousterian stone tools and bones of a number of regionally extinct megafauna, including Elephas primigenius, Rhinoceros tichorhinus, Bos primigenius, Bos priscus, Equus caballus, as well as the regionally surviving species of Rangifer tarandus.
Ancient nomadic tribes subsisted near the banks of the Yenisei, whose present day survivors include the Ket and Yugh peoples. It is also worthwhile to note that ice bridge immigrants arriving in North America around 15,000 years ago are likely to have come from Siberia, possibly from the Yenisei basin.
References
- A.P.Abaimov, J.A.Lesinski, O.Martinsson, and L.I.Milyutin. 1998. Variability and ecology of Siberian larch species. Swedish University of Agricultural Sciences. Department of Silviculture. Report 43.
- Fishbase. 2010. Species in the Yenisei
- M.I.Gladyshev and A.V.Moskvichev. 2001. Baikal Invaders Have Become Dominant in the Upper Yenisei Benthofauna. Doklady Biological Sciences Volume 383, Numbers 1-6, 138-140. Springerlink Publishing
- C. Michael Hogan. 2009. Hooded Crow: Corvus cornix, GlobalTwitcher.com, ed, N. Stromberg
- Vyacheslav Ivanov and Vladimir Toporov. 1973. Towards the Description of Ket Semiotic Systems. Semiotica. The Hague, Prague, New York: Mouton) IX (4): 318–346.
- Ola M.Johannessen, Vladimir A.Volkov, Lasse H.Pettersson. 2010. Polar Seas Oceanography: Radionuclides in the Arctic. 500 pages. Springer Publishing. Google eBook
- S.Kurnaev. 1990. Forest regionalization of the USSR (1:16,000,000). Department of Geodesy and Cartography, Moscow.
- J.Mangerud et al. 2004. Ice-dammed lakes and rerouting of the drainage of northern Eurasia during the Last Glaciation. Quaternary Science pp. 1313–1332
- Gero von Merhart. 1923. The Palaeolithic Period in Siberia: Contributions to the Prehistory of the Yenisei Region. www.jstor.org
- Ruediger Stein et al. 2003. Siberian river run-off in the Kara Sea, Proceedings in Marine Sciences, Elsevier, Amsterdam, 488 pages
- B.K.Sharma. Water Pollution. Krishna Prakashan Media. books.google.com
