Sergey Zimov

Sergey Aphanasievich Zimov
File:Zimov.jpg S.A. Zimov overlooking the Siberian landscape
Born	July 1955
Residence	Sakha Republic, Russia
Institutions	Northeast Science Station, Cherskii, RU
Alma mater	Far East State University, Vladivostok, Russia
Known for	The Northeast Science Station, Pleistocene Park, global carbon and methane cycles, Pleistocene ecosystem reconstruction
Notable awards	Wolf Vishniac Award (1991)

Sergey Aphanasievich Zimov (Russian: Серге́й Афанасьевич Зимов) is a Russian scientist who serves as the Director of the Northeast Science Station and is one of the founders of Pleistocene Park. He is best known for his work in advocating the theory that human overhunting of large herbivores during the Pleistocene caused Siberia’s grassland-steppe ecosystem to disappear and for raising awareness as to the important roles permafrost and thermokarst lakes play in the global carbon cycle.

Life and work

Sergei Zimov is a Russian scientist who resides in Cherskii, Sakha Republic, Russia. He studied and received his degree in geophysics from Far East State University, located in Vladivostok, Russia.

Zimov founded the Northeast Science near Cherskii in 1977. Twelve years later, in 1988, he initiated the Pleistocene Park project. In 1991, Sergei Zimov was awarded the Wolf Vishniac Award at the fourth International Society for Environmental Biochemistry conference.

Professional highlights and accomplishments

Northeast Science Station

Coordinates: 69 degrees 30 minutes North latitude, 161 degrees 30 minutes East longitude

File:Northeast Science Station.jpg

Overview of the Northeast Science Station, Cherskii, Russia

File:Northeast Science Station View.jpg

View from the Northeast Science Station

Sergei Zimov is the director of the Northeast Science Station. Located near Cherskii, Russia on the mouth of the Kolyma River, 150 kilometers south of the Arctic Ocean, the station serves as a year-round base for international Arctic research. Founded in 1977, the Northeast Science Station boasts three laboratories, a network of field sites, tools for data analysis and communication, transportation, accommodation for visiting researchers, and a year round staff of six. A barge floating on the Kolyma River serves as a traveling dormitory and laboratory.

Permafrost and methane

In collaboration with Dr. Terry Chapin and Dr. Katey Walter-Anthony, Sergei Zimov has published a series a collection of scientific papers exposing the importance of permafrost and high-latitude carbon dioxide and methane emissions in the global carbon cycle. These papers identified methane ebullition from thermokarst lakes to be a significant source of atmospheric methane, a potent greenhouse gas.

Permafrost is a large global carbon reservoir which has remained frozen throughout much of the Holocene. Due to recent climate change, the permafrost is beginning to thaw, releasing stored carbon and forming thermokarst lakes. When the thawed permafrost enters the thermokarst lakes, its carbon is converted into carbon dioxide and methane and released into the atmosphere. Methane is a potent greenhouse gas and the methane emissions from thermokarst lakes have the potential to initiate a positive feedback cycle in which increased atmospheric methane concentrations lead to amplified global climate change, which in turn leads to more permafrost thaw and more methane and carbon dioxide emissions.

Pleistocene Park

For more information see Pleistocene Park

Restored grasslands in Pleistocene Park

Zimov initiated the Pleistocene Park project in 1988 in Northeast Siberia near the Northeast Science Station in Cherskii, Republic of Sakha, Russia. Pleistocene Park seeks to test the hypotheses that large herbivores maintained the Pleistocene tundra steppe and that overhunting by humans caused both the animals and Pleistocene ecosystem to vanish.

The grassland-steppe ecosystem which dominated Siberia during the Pleistocene disappeared 10,000 years ago and was replaced by mossy and forested tundra. Concurrently, many of the large herbivores who roamed Siberia during the Pleistocene, including mammoths, woolly rhinoceroses, bison, horses, musk oxen, elk, saiga, and yaks, vanished from the region. Today, reindeer and moose are the only surviving large herbivores to roam Siberia. Zimov and colleagues believe that humans, with their constantly improving technology, overhunted the large herbivores and led to their extinction and extirpation. Without herbivores grazing and trampling over the land, mosses, shrubs, and trees were able to take over and replace the grassland ecosystem.

At Pleistocene Park, Zimov is attempting to recreate the Pleistocene grasslands to demonstrate that the grasslands would have persisted into the Holocene if humans did not overhunt the herds of Pleistocene herbivores which roamed and maintained the ecosystem. He has demonstrated that grasses take over the landscape 1–2 years after mosses are anthropogenically removed. According to Zimov, re-introducing large herbivores to Siberia would initiate a positive feedback loop promoting the reestablishment of grassland ecosystems: “The animals, their hooves, they disturb the moss and let grasses grow instead. The soil dries out, the animals deposit their fertilizer, the grass grows more, and more animals can graze.”

Current efforts in the park include reintroducing surviving Pleistocene megafauna into the fenced enclosure until they reach densities to change the vegetation and soil to a steppe grassland ecosystem. Pleistocene Park currently covers an area of 160 square kilometers and contains less than 100 large mammals representing six major herbivore species (horses, moose, reindeer, muskox, elk, and bison). Zimov’s goal for Pleistocene Park is to increase the number of large herbivores to 20 per square kilometer then begin reintroducing predators, including wolves, bears, and Siberian tigers.

Selected publications

• Walter, K.M., M. E. Edwards, G. Grosse, S. A. Zimov, F. S. Chapin III. "Thermokarst Lakes as a Source of Atmospheric CH₄ During the Last Deglaciation." Science 318.5850 (2007): 633-636. http://www.sciencemag.org/cgi/content/short/318/5850/633
  • This paper estimates that 33-87% of high-latitude increases in atmospheric methane originate from thermokarst lakes. It is suggested that sediments which have been frozen since the Pleistocene, called yedoma, will have high methane-releasing potential as they thaw due to climate change.
• Walter, K.M., S. A. Zimov, J. P. Chanton, D. Verbyla & F. S. Chapin III. "Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming." Nature 443.7107 (2006): 71-75. http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html
  • This paper quantifies methane emissions from thermokarst lakes in North Siberia. Most of the methane is sourced to thawing permafrost from the lake margins.
• Zimov, S.A. "Pleistocene Park: Return of the Mammoth's Ecosystem." Science 308.5723 (2005): 796-798. http://www.sciencemag.org/cgi/reprint/308/5723/796.pdf
  • This essay outlines the concept behind Pleistocene Park, Sergei Zimov’s research site in which he seeks to demonstrate that human overhunting of Pleistocene megafauna led to the disappearance of the Pleistocene’s grassland-steppe ecosystem.
• Zimov S.A., S.P. Daviodov, G.M. Zimova, A.I. Davidova, F.S. Chapin III, M.C. Chapin, J.F. Reynolds. "Contribution of Disturbance to Increasing Seasonal Amplitude of Atmospheric CO₂." Science 284.5422 (1999): 1973. http://www.sciencemag.org/cgi/content/full/sci;284/5422/1973
  • This paper suggests that increasing high-latitude ecological disturbances such as fires and grazing contribute to the long-term increase in atmospheric carbon dioxide.
• Zimov, S.A., E.A.G. Schuur, F. S. Chapin III. "Permafrost and the Global Carbon Budget." Science 312.5780 (2006): 1612-1613. http://www.sciencemag.org/cgi/content/full/312/5780/1612
  • This paper contends that permafrost represents a significant global carbon sink. As climate change causes permafrost to thaw, the stored carbon will be released and amplify global climate change.
• Zimov S.A., Y.V. Voropaev, I.P. Semiletov, S.P. Davidov, S.F. Prosiannikov, F.S. Chapin III, M.C. Chapin, S. Trumbore, S. Tyler. "North Siberian Lakes: A methane source fueled by Pleistocene carbon." Science 277.5327 (1997): 800. http://www.sciencemag.org/cgi/content/full/277/5327/800?ck=nck
  • This paper identifies Pleistocene-aged soils, referred to as yedoma, as being a major carbon source for methane emissions from thermokarst lakes in North Siberia.

External links

• The Official Pleistocene Park and Northeast Science Station Website http://www.pleistocenepark.ru/en/
• The Northeast Science Station http://terrychapin.org/station.html