Impact of climate change and industrialization on remote Lake Bolshoe Toko, Siberia

To test if recent climate change and pollution affected remote lake ecosystems without direct human influence, we used paleolimnological methods on lake sediments from a large, prestine, and deep lake in Yakutia, Russia. We compared diatoms and sediment-geochemistry from before and after the onset of industrialization in the mid-nineteenth century, at water depths between 12.1 and 68.3 m in Lake Bolshoe Toko. We analyzed diatom species changes and geochemical changes including mercury concentrations. Chronologies were established using 210Pb and 137Cs revealing sedimentation rates between 0.018 and 0.033 cm y-1 at shallow- and deep-water sites, respectively. Increase in light planktonic diatoms (Cyclotella) and decrease in heavily silicified euplanktonic Aulacoseira through time at deep-water sites can be related to warming air temperatures and shorter periods of lake-ice cover, causing pronounced thermal stratification. Diatom beta diversity changed only significantly in shallow-water communities which can be related to the development of new habitats with macrophyte growth. Mercury concentrations increased by a factor of 1.6 as a result of atmospheric fallout. Increases in the chrysophyte Mallomonas indicates a trend towards acidification. We conclude that also remote boreal lakes are susceptible to human-induced long-distance pollution and recent climate change.

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Effects of climate change and industrialization on Lake Bolshoe Toko, eastern Siberia

Journal of Paleolimnology ◽

10.1007/s10933-021-00175-z ◽

2021 ◽

Vol 65 (3) ◽

pp. 335-352

Author(s):

Boris K. Biskaborn ◽

Biljana Narancic ◽

Kathleen R. Stoof-Leichsenring ◽

Lyudmila A. Pestryakova ◽

Peter G. Appleby ◽

...

Keyword(s):

Climate Change ◽

Nineteenth Century ◽

Deep Water ◽

Boreal Lakes ◽

Lake Ecosystem ◽

Intermediate Water ◽

Eastern Siberia ◽

Natural Ecosystems ◽

Planktonic Diatoms ◽

Recent Climate

AbstractIndustrialization in the Northern Hemisphere has led to warming and pollution of natural ecosystems. We used paleolimnological methods to explore whether recent climate change and/or pollution had affected a very remote lake ecosystem, i.e. one without nearby direct human influence. We compared sediment samples that date from before and after the onset of industrialization in the mid-nineteenth century, from four short cores taken at water depths between 12.1 and 68.3 m in Lake Bolshoe Toko, eastern Siberia. We analyzed diatom assemblage changes, including diversity estimates, in all four cores and geochemical changes (mercury, nitrogen, organic carbon) from one core taken at an intermediate water depth. Chronologies for two cores were established using 210Pb and 137Cs. Sedimentation rates were 0.018 and 0.033 cm year−1 at the shallow- and deep-water sites, respectively. We discovered an increase in light planktonic diatoms (Cyclotella) and a decrease in heavily silicified euplanktonic Aulacoseira through time at deep-water sites, related to more recent warmer air temperatures and shorter periods of lake-ice cover, which led to pronounced thermal stratification. Diatom beta diversity in shallow-water communities changed significantly because of the development of new habitats associated with macrophyte growth. Mercury concentrations increased by a factor of 1.6 since the mid-nineteenth century as a result of atmospheric fallout. Recent increases in the chrysophyte Mallomonas in all cores suggested an acidification trend. We conclude that even remote boreal lakes are susceptible to the effects of climate change and human-induced pollution.

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