Lake sediment records of persistent organic pollutants and polycyclic aromatic hydrocarbons in Southern Siberia mirror the changing fortunes of the Russian economy over the past 70 years

Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) have previously been detected in the surface sediments, water, and endemic organisms of Lake Baikal, a UNESCO World Heritage Site. The Selenga River is the primary source of freshwater to Lake Baikal, and transports pollutants accumulating in the Selenga River basin to the lake. Sources of POPs and PAHs in the Selenga River basin grew through the 20th century. In the present study, temporal changes in the concentrations of PAHs and POPs were reconstructed from two lakes in the Selenga River basin over the past 150 years using paleolimnological techniques. Increased concentrations in PAHs and PCBs were recorded initially in the 1930s. The 1940s–1980s was the period of greatest exposure to organic contamination, and concentrations of dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs) and many PAHs peaked between the 1960s and 1980s in the two lakes. Declines in concentrations and fluxes were recorded for most PAHs and POPs in the 1980s and 1990s. Temporal trends in concentrations of total and individual compounds/congeners of PAH, PCBs, and polybrominated diphenyl ethers (PBDEs) indicate the contribution of both local and regional sources of contamination in the 20th and 21st centuries. Temporal variations in contaminants can be linked to economic and industrial growth in the former USSR after World War II and the economic decline of Russia in the late-1980s and early-1990s, as well as global trends in industrialization and development during the mid-20th century

A Holocene floodplain sequence from the Kirenga Valley, Lake Baikal region (Siberia), and its significance for molluscan and mammalian biogeography

The archaeological record in the Baikal region is characterised by a marked discontinuity separating different groups of hunter-gatherers within the Neolithic period. A range of sedimentary archives has been studied to investigate this issue and whether it had an environmental cause. Our focus has been on floodplain sequences from river valleys, which can augment other higher resolution records such as those from lakes. Here we report on the molluscs and small vertebrates recovered from a Holocene floodplain sequence at a remote locality (Krasniy Yar XI) in the Kirenga Valley, in the Lake Baikal region of eastern Siberia. The sequence lacked the necessary temporal resolution to adequately address this archaeological question, but it did provide a valuable radiocarbon-dated record of local floodplain pedogenesis, molluscs and vertebrates over the last ∼7000 cal yr BP. Aquatic molluscs are more frequent during the early part of the record but they become scarce in the upper levels, which are dominated by land snails, especially species of Vallonia. Other noteworthy species include Vertigo microsphaera, recently discovered living in the area, and the first fossil records of V. kushiorensis, V. chytryi, and V. genesioides from the Baikal region. An exceptional feature of the molluscan record was the relatively high frequency of sinistral specimens of Cochlicopa, which occurred in 12/18 samples with a mean frequency of 9.8% (38/385). The vertebrates included specimens of southern birch mouse Sicista subtilis, unknown living in this part of Siberia with the closest records some 400 km to the southwest. These data demonstrate marked faunal and distributional shifts within the Holocene, reflecting local and regional environmental changes through time

Diatom community responses to long-term multiple stressors at Lake Gusinoye, Siberia

The information, practices and views in this article are those of the author(s) and do not necessarily reflect the opinion of the Royal Geographical Society (with IBG). © 2019 The Authors. Geo: Geography and Environment published by John Wiley & Sons Ltd and the Royal Geographical Society (with the Institute of British Geographers). Global freshwater systems are threatened by multiple anthropogenic stressors via impacts on ecological structure and function necessary to maintain their health. In order to properly manage freshwater ecosystems, we must have a better understanding of the ecological response to human-induced stressors, especially in multiple stressor environments. When long-term observational records are scarce or non-existent, paleolimnology provides a means to understanding ecological response to long-term stress. Lake Gusinoye is a large, deep lake in continental southeast Siberia, and has been subject to multiple human-induced stressors since the 19th century. Diatom assemblages since the late 17th century were reconstructed from a Lake Gusinoye sediment core to increase our understanding of the response of primary producer communities to centuries of environmental change. Records of anthropogenic contamination of Lake Gusinoye (as indicated by spheroidal carbonaceous particle, trace metal, and element records) indicate increases in regional and local development c. 1920. Diatom assemblages were initially dominated by Aulacoseira granulata, which declined beginning in the 18th century, likely as a response to hydrological change in the Gusinoye basin due to regional climate warming following the termination of the Little Ice Age (LIA). Significant diatom compositional turnover was observed since the 19th century at Lake Gusinoye. Since the early 20th century, Lake Gusinoye diatom assemblages have changed more profoundly as a result of multiple anthropogenic stressors, including nutrient influx, aquaculture, and wastewater discharge from the Gusinoozersk State Regional Power Plant. Recent diatom assemblages are dominated by Lindavia ocellata and nutrient-rich species, including Fragilaria crotonensis and Asterionella formosa. Evidence of continued nutrient enrichment at Lake Gusinoye is likely due to aquaculture in the lake, and suggests potential interactive effects of warming regional temperatures and increasing nutrients (eutrophication)