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

Abstract

Industrialization 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.

Sediment and carbon accumulation in a glacial lake in Chukotka (Arctic Siberia) during the Late Pleistocene and Holocene: combining hydroacoustic profiling and down-core analyses

“…Further methodological uncertainty can arise through oversimplified estimation of dry bulk density (DBD) from empirical equations of DBD and carbon content where discrete, volumetric measurements do not exist (Avnimelech et al, 2001;Kastowski et al, 2011) as well as varied approaches used for the measurement of sample carbon contents (elemental analyser vs. loss on ignition (LOI)) (Munroe and Brencher, 2019). Limitations associated with radiocarbon dating of Arctic glacial lakes due to the absence of appreciable amounts of datable organic material, particularly during glacial phases as well as the reworking of old organic carbon present within catchment sediments that can be brought to the lake basin through permafrost and glacial processes during warm and cold phases respectively, can additionally lead to uncertainty with regards to sediment ages and hence reconstructed accumulation rates (Abbott and Stafford, 1996;Björck and Wohlfarth 2002;Oswald et al, 2005). Despite this, the calculated OCARs and pools for Lake Rauchuagytgyn are largely agreeable with multiple studies from northern regions and reinforce the reliability, applicability and novelty of the presented results.…”

Wildfire history of the boreal forest of south-western Yakutia (Siberia) over the last two millennia documented by a lake-sediment charcoal record

“…sults, an age-depth model was computed using Bacon v.2.4.3 (Blaauw and Christen, 2011;package "rbacon";Blaauw et al, 2020), combining Pb/Cs and adjusted 14 C ages of all bulk samples calibrated with the IntCal20 14 C calibration curve (Reimer et al, 2020).…”

“…30 and 40 km distance, respectively). It has also been shown that even very remote lake systems in Yakutia have been affected by human activity from industrialization (Biskaborn et al, 2021). Yakutia has been populated by humans since at least ca.…”

Late Quaternary Climate Reconstruction and Lead-Lag Relationships of Biotic and Sediment-Geochemical Indicators at Lake Bolshoe Toko, Siberia

“…Today, the sedimentary basin of Lake Bolshoe Toko is 15 km long and 8 km wide, situated at the northern foot of the Stanovoy Mountains representing most of the lake's catchment (Biskaborn et al, 2021). The Bolshoe Toko basin forms a surficial landform on the southeastern Siberian Platform, which is built up of cratonic basement rocks of Precambrian age and overlain by Paleozoic to Mesozoic sedimentary rock strata and Quaternary cover sediments, in places with intercalated volcanic rock units (Nikishin et al, 2010;Barnet and Steiner, 2021).…”

“…Although the Siberian region is generally regarded as being underrepresented in paleoenvironmental research (Sundqvist et al, 2014;Mckay et al, 2018;Kaufman et al, 2020), there is an ever-expanding interest in the area due to expected environmental changes and associated strong socioenvironmental implications (Amap, 2017). In particular, remote Arctic lakes in permafrost regions represent pristine earlywarning systems of environmental change, as they rapidly respond to climatic perturbations and changes in geoecological boundary conditions in their catchments (Subetto et al, 2017;Biskaborn et al, 2021;Nazarova L. B. et al, 2021). In terms of environmental sustainability, they still provide an infinite resource of uncontaminated fresh water, which make them unique compared to lake systems in the highly populated mid-latitude areas (Serreze et al, 2006).…”