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Holocene climatic and environmental changes inferred from midge records (Diptera : Chironomidae, Chaoboridae, Ceratopogonidae) at Lake Berkut, southern Kola Peninsula, Russia

Ilyashuk, EA; Ilyashuk, BP; Hammarlund, Dan LU and Larocque, I (2005) In The Holocene 15(6). p.897-914
Abstract
A radiocarbon-dated sediment sequence from Lake Berkut in the southern part of the Kola Peninsula, northwest Russia, was investigated by means of midge analysis in order to reconstruct the Holocene climatic and environmental history of the region. Past mean July air temperatures at the study site and hypolimnetic oxygen contents of the lake water were inferred from chironomid-based transfer functions. The early Holocene (c. 10 100 - 8400 cal. yr BP) is characterized by summer temperatures and hypolimnetic oxygen concentrations broadly similar to present-day conditions. The midge records give evidence of a lake- level fall at c. 7000 cal. yr BP, resulting in weakened thermal stratification of the lake water, and improvement of the... (More)
A radiocarbon-dated sediment sequence from Lake Berkut in the southern part of the Kola Peninsula, northwest Russia, was investigated by means of midge analysis in order to reconstruct the Holocene climatic and environmental history of the region. Past mean July air temperatures at the study site and hypolimnetic oxygen contents of the lake water were inferred from chironomid-based transfer functions. The early Holocene (c. 10 100 - 8400 cal. yr BP) is characterized by summer temperatures and hypolimnetic oxygen concentrations broadly similar to present-day conditions. The midge records give evidence of a lake- level fall at c. 7000 cal. yr BP, resulting in weakened thermal stratification of the lake water, and improvement of the hypolimnetic oxygen conditions. After c. 4000 cal. yr BP midge assemblages suggest a lake- level rise related to increased effective moisture. A secondary mid-Holocene climatic optimum with inferred mean July air temperatures of c. 12.1 degrees C was recorded between 6000 and 4400 cal. yr BP, followed by minimum values (c. 11.3 degrees C) between 3500 and 1500 cal. yr BP, accompanied by the onset of natural acidification of the lake. The late-Holocene midge assemblages suggest weakly acidic conditions, low hypolimnetic oxygen contents and a general warming trend during the last c. 1500 years, although paludification and natural acidification may have influenced the temperature reconstruction at this stage. However, the modern chironomid-inferred mean July air temperature (12.5 degrees C) is consistent with meteorological data from a nearby station. In general, the midge records reflect relatively warm and moist conditions at Lake Berkut before c. 7000 cal. yr BP, a relatively warm and dry climate at c. 7000 - 4000 cal. yr BP, and a shift to cooler and wetter climatic conditions in the region after c. 4000 cal. yr BP. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
hypolimnetic oxygen content, effective moisture, temperature, July, Diptera, insect remains, palaeoclimate, lake sediments, Kola, Peninsula, Russia, Holocene
in
The Holocene
volume
15
issue
6
pages
897 - 914
publisher
SAGE Publications Inc.
external identifiers
  • wos:000231527900011
  • scopus:25444464683
ISSN
0959-6836
DOI
10.1191/0959683605hl865ra
language
English
LU publication?
yes
id
fd510918-09c1-4caf-98e1-531a9b12aea4 (old id 226344)
date added to LUP
2007-08-14 14:15:24
date last changed
2017-10-22 03:43:04
@article{fd510918-09c1-4caf-98e1-531a9b12aea4,
  abstract     = {A radiocarbon-dated sediment sequence from Lake Berkut in the southern part of the Kola Peninsula, northwest Russia, was investigated by means of midge analysis in order to reconstruct the Holocene climatic and environmental history of the region. Past mean July air temperatures at the study site and hypolimnetic oxygen contents of the lake water were inferred from chironomid-based transfer functions. The early Holocene (c. 10 100 - 8400 cal. yr BP) is characterized by summer temperatures and hypolimnetic oxygen concentrations broadly similar to present-day conditions. The midge records give evidence of a lake- level fall at c. 7000 cal. yr BP, resulting in weakened thermal stratification of the lake water, and improvement of the hypolimnetic oxygen conditions. After c. 4000 cal. yr BP midge assemblages suggest a lake- level rise related to increased effective moisture. A secondary mid-Holocene climatic optimum with inferred mean July air temperatures of c. 12.1 degrees C was recorded between 6000 and 4400 cal. yr BP, followed by minimum values (c. 11.3 degrees C) between 3500 and 1500 cal. yr BP, accompanied by the onset of natural acidification of the lake. The late-Holocene midge assemblages suggest weakly acidic conditions, low hypolimnetic oxygen contents and a general warming trend during the last c. 1500 years, although paludification and natural acidification may have influenced the temperature reconstruction at this stage. However, the modern chironomid-inferred mean July air temperature (12.5 degrees C) is consistent with meteorological data from a nearby station. In general, the midge records reflect relatively warm and moist conditions at Lake Berkut before c. 7000 cal. yr BP, a relatively warm and dry climate at c. 7000 - 4000 cal. yr BP, and a shift to cooler and wetter climatic conditions in the region after c. 4000 cal. yr BP.},
  author       = {Ilyashuk, EA and Ilyashuk, BP and Hammarlund, Dan and Larocque, I},
  issn         = {0959-6836},
  keyword      = {hypolimnetic oxygen content,effective moisture,temperature,July,Diptera,insect remains,palaeoclimate,lake sediments,Kola,Peninsula,Russia,Holocene},
  language     = {eng},
  number       = {6},
  pages        = {897--914},
  publisher    = {SAGE Publications Inc.},
  series       = {The Holocene},
  title        = {Holocene climatic and environmental changes inferred from midge records (Diptera : Chironomidae, Chaoboridae, Ceratopogonidae) at Lake Berkut, southern Kola Peninsula, Russia},
  url          = {http://dx.doi.org/10.1191/0959683605hl865ra},
  volume       = {15},
  year         = {2005},
}