Diatom oxygen isotope records of Northern Eurasia as indicators of environmental, hydrological and climate changes in the regions

S. Kostrova; H. Bailey; B. Biskaborn; B. Chapligin; Y. Dvornikov; A. Ekaykin; F. Fernandoy; A. Kozachek; G. Kuhn; A. Ludikova; P. Meister; L. Nazarova; L. Pestryakova; Y. Shibaev; L. Syrykh; H. Meyer

doi:10.31951/2658-3518-2022-A-4-1444

Diatom oxygen isotope records of Northern Eurasia as indicators of environmental, hydrological and climate changes in the regions

Authors: Kostrova S.¹, Bailey H.², Biskaborn B.¹, Chapligin B.¹, Dvornikov Y.³, Ekaykin A.⁴, Fernandoy F.⁵, Kozachek A.⁴, Kuhn G.⁶, Ludikova A.⁷, Meister P.¹, Nazarova L.¹, Pestryakova L.⁸, Shibaev Y.⁴, Syrykh L.⁹, Meyer H.¹
Affiliations:
1. Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Research Unit Potsdam
2. University of Oulu
3. Agrarian-Technological Institute, Рeoples’ Friendship University of Russia (RUDN University)
4. Arctic and Antarctic Research Institute
5. Universidad Andrés Bello
6. Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research
7. Institute of Limnology SPC RAS
8. North-Eastern Federal University of Yakutsk, Institute of Natural Sciences
9. Herzen State Pedagogical University of Russia
Issue: No 4 (2022)
Pages: 1444-1446
Section: Articles
URL: https://journal-vniispk.ru/2658-3518/article/view/289387
DOI: https://doi.org/10.31951/2658-3518-2022-A-4-1444
ID: 289387

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Abstract

The environmental, hydrological and climate dynamics were assessed in Northern Eurasia during the Holocene. The reconstructions are based on oxygen isotope composition of lacustrine diatom silica (δ¹⁸O_diatom) preserved in sediment cores from Ladoga, Bolshoye Shchuchye and Emanda lakes. Interpretation of the δ¹⁸O_diatom data is supported by a comprehensive study of modern isotope hydrology and analysis of local and regional proxies. The Northern Eurasia δ¹⁸O_diatom records are characterized by pronounced short term variations (1.5–5‰), pointing to the unstable climatic and hydrological conditions in the study regions. All records have clearly demonstrated a gradual depletion over the Holocene in their δ¹⁸O_diatom values by ~3–4‰, which follows the trend of decreasing summer insolation, as well as the temperature history of the Northern Hemisphere (NH), indicating a positive response of diatom oxygen isotope signal to large-scale climate changes.

Keywords

stable oxygen isotopes, hydrological fluctuations, diatoms, climate change, lake sediments

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1. Introduction

Lacustrine sediments are reliable archives, providing fundamental information on environmental and climate changes since the formation of a lake system (e.g. Subetto et al., 2017). In the last decades, diatom oxygen isotope analysis has become a dependable tool to trace hydrological and climate dynamics in individual lake catchments. Generally related to lake temperature (T_lake) and water isotope variations (δ¹⁸O_lake), δ¹⁸O_diatom perfectly reflects these changes and is commonly applied in palaeoenvironmental and/or climatic reconstructions especially for northern regions where ice archives are unavailable and/or biogenic carbonates limited (e.g. Swann and Leng, 2009).

In the current study, the environmental, hydrological and climatic variability was reconstructed from sediment cores of lakes located along a ~6000 km transect across Northern Eurasia, using diatom oxygen isotopes in the context of modern hydrology and other relevant local (diatom taxonomy, chironomid and biogeochemical analyses, isotope mass balance model) and regional parameters (modern moisture origin and digital elevation models). Combining the newly obtained δ¹⁸O_diatom records with other regional and hemispheric reconstructions provides a complementary assessment of environmental conditions in normally intact, remote lake systems.

2. Materials and methods

The sediment cores Co1309, Co1321, Co1412 were respectively recovered from lakes Ladoga (60°59’ N, 30°41’ E; water depth: 111 m); Bolshoye Shchuchye (67°53’ N, 66°19’ E; water depth: 136 m); Emanda (65°18’ N, 135°46’ E; water depth: 14.6 m) during the drilling campaign within the German-Russian Paleolimnological Transect (PLOT) project (Fedorov et al., 2020), using gravity and percussion piston-corers operated from a floating platform (UWITEC Ltd., Austria).

Separation and cleaning of diatoms from the sediment matrix was carried out using a multistep process of wet chemistry, sieving, and heavy liquid separation described in detail in Kostrova et al. (2019; 2021). The oxygen isotope composition of purified diatom samples was measured at the ISOLAB Facility at AWI Potsdam with a PDZ Europa 2020 mass spectrometer using the laser fluorination method (Chapligin et al., 2010). A geochemical mass-balance approach (Chapligin et al., 2012) was applied for contamination correction of the measured δ¹⁸O values.

3. Results and discussion

The δ¹⁸O_diatom values from Lake Ladoga range from +29.8 to +35.0‰. The relatively high values between ~7.1 and 5.7 cal. ka BP are interpreted to indicate the Holocene Thermal Maximum (HTM). A continuous depletion in δ¹⁸O_diatom after 6.1 cal. ka BP is related to Middle to Late Holocene cooling, which culminated in the interval 0.8–0.2 cal. ka BP corresponding to the Little Ice Age (LIA). Elevations/declines of the lake water level are accompanied by fluctuations in δ¹⁸O_diatom towards lower/higher values, respectively. Thus, relatively low δ¹⁸O_diatom values at ~10.7 cal. ka BP indicate that the lake existed as an eastern deep bay of the Ancylus Lake. The regression of the Baltic Sea and the formation of Lake Ladoga as an independent reservoir were accompanied by a decrease of the lake level and characterized by relatively higher δ¹⁸O_diatom. Between ~5.7 and 4.4 cal. ka BP, a decline in δ¹⁸O_diatom values could reflect a lake level rise caused by the formation of a new inflow to the lake via River Vuoksi. The subsequent increase of δ¹⁸O_diatom at 4.4–4.0 cal. ka BP gives an indication for a rather early opening of the Neva River outflow. An accelerated decrease in δ¹⁸O_diatom after 4.0 cal. ka BP probably reflects an overall cooling with more persistent lake ice cover and reduced evaporation.

The Lake Bolshoye Shchuchye δ¹⁸O_diatom record exhibits variations between +23.4 and +31.8‰. The short term (centennial-scale) variations often exceeding 5‰, especially in Middle and Late Holocene, are superimposed on the general decreasing trend. These fluctuations occur contemporaneously with and similarly to Holocene NH glacier advances. However, large Holocene glacier advances in the Lake Bolshoye Shchuchye catchment are unknown and have not left any significant imprint on the lake sediment record. Consequently, to explain the observed shifts for the deep and voluminous lake, about 30−50% of its volume should be replaced by isotopically different water within decades. Snow, which is known to be transported in surplus by redistribution from the windward to the leeward side of the Polar Urals, is considered a likely source of water with a light isotope composition. Snow melt and influx changes are assumed to be the dominant mechanism responsible for the short term changes in the δ¹⁸O_diatom record.

The δ¹⁸O_diatom values from Lake Emanda vary from +22.5‰ to +27.8‰. An obvious shift in δ¹⁸O_diatom at 11.7–11.5 cal. ka BP reflects the onset of the Holocene. Relatively high δ¹⁸O_diatom during the Early Holocene suggests relatively warm and/or dry climate with associated evaporation effects. The absolute maximum in the record at ~7.9−7.0 cal. ka BP is supposed to be a Middle HTM. A continuous depletion in δ¹⁸O_diatom values since ~5.0 cal. ka BP reaching the absolute minimum at 0.4 cal. ka BP is interpreted as Middle to Late Holocene cooling culminated at the LIA and associated with colder T_air, a more persistent lake ice cover and reduced evaporation. The pattern of the Lake Emanda δ¹⁸O_diatom record is close to that obtained from Lake El’gygytgyn (Swann et al., 2010).

All δ¹⁸O_diatom records follow a decrease in summer insolation and are in line with the regional and the NH temperature history, demonstrating a good response of the isotope signal to insolation-driven temperature changes. A consistent decrease in δ¹⁸O_diatom is observed in the records from ~6.5–5.2 cal. ka BP, indicating Middle to Late Holocene cooling.

4. Conclusions

The Holocene oxygen isotope records on fossil diatoms extracted from sediment cores of lakes Ladoga, Bolshoye Shchuchye and Emanda are combined with the recent isotope hydrology and local proxy’s data, and used to characterize the environmental, hydrological and climate variability in Northern Eurasia. The data revealed that all lakes existed during the Holocene as well-mixed freshwater bodies without any evidence of a brackish or marine environment. The variability of δ¹⁸O_diatom is mainly controlled by changes in δ¹⁸O_lake rather than changes in T_lake. However, in Ladoga and Emanda lakes it is also associated with enhanced evaporation effects, whereas evaporative effects are negligible in Lake Bolshoye Shchuchye. Here, local snowmelt may change the local δ¹⁸O_lake.

The Lake Ladoga region has undergone significant hydrological changes throughout the Holocene. The isolation of the lake basin in the Early Holocene, the subsequent opening of the Vuoksi River inflow at ~5.7 cal. ka BP and the formation of the Neva River outflow at ~ 4.4–4.0 cal. ka BP are accompanied by lake level changes and notable as respective maxima and minima in the δ¹⁸O_diatom record.

The Lake Bolshoye Shchuchye δ¹⁸O_diatom record displays short term, centennial-scale changes attributed to snow transport to the catchment and switch on/off of meltwater supply to the lake. The δ¹⁸O_diatom signal is interpreted as indicator for palaeoprecipitation, whereas the decreasing long-term trend in the record follows summer temperature changes.

The Lake Emanda δ¹⁸O_diatom record demonstrates striking similarity to that obtained from Lake El’gygytgyn (Swann et al., 2010) despite obvious hydrological differences, suggesting a common “eastern” regional signal in both records.

Acknowledgements

The study was performed in the frame of the German-Russian projects ‘PLOT − Paleolimnological Transect’ (BMBF; grant 03G0859) and its successor ‘PLOT – Synthesis’ (BMBF; grant 03F0830C) both funded by the German Federal Ministry of Education and Research. The work of A. Ludikova contributes to the State Research Program of the IL RAS № 0154-2019-0001.

Conflict of interest

The authors declare no conflict of interest.

About the authors

S. Kostrova

Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Research Unit Potsdam

Author for correspondence.
Email: Svetlana.Kostrova@gmail.com
Germany, Telegrafenberg A45, Potsdam, 14473

H. Bailey

University of Oulu

Email: Svetlana.Kostrova@gmail.com

Department of Ecology and Genetics

Finland, Oulu, 90014

Department of Landscape Design and Sustainable Ecosystems

Russian Federation, Miklukho-Maklaya Str., 6, Moscow, 117198

A. Ekaykin

Arctic and Antarctic Research Institute

Email: Svetlana.Kostrova@gmail.com
Russian Federation, Bering Str., 38, St. Petersburg, 199397

F. Fernandoy

Universidad Andrés Bello

Email: Svetlana.Kostrova@gmail.com

Laboratorio de análisis isotópico, Facultad de Ingeniería

Chile, Quillota Str., 980, Viña del Mar, 2531015

References

Chapligin B., Meyer H., Bryan A. et al. 2012. Assessment of purification and contamination correction methods for analysing the oxygen isotope composition from biogenic silica. Chemical Geology 300-301: 185-199. doi: 10.1016/j.chemgeo.2012.01.004
Chapligin B., Meyer H., Friedrichsen H. et al. 2010. A high-performance, safer and semi-automated approach for the δ18O analysis of diatom silica and new methods for removing exchangeable oxygen. Rapid Communications in Mass Spectrometry 24: 2655-2664. doi: 10.1002/rcm.4689
Fedorov G., Andreev A., Baumer M. et al. 2020. Northern Eurasian large lakes history: sediment records obtained in the frame of Russian-German research project “PLOT”. Limnology and Freshwater Biology 2020(4): 517-519. doi: 10.31951/2658-3518-2020-A4-517
Kostrova S.S., Biskaborn B.K., Pestryakova L.A. et al. 2021. Climate and environmental changes of the Lateglacial transition and Holocene in northeastern Siberia: evidence from diatom oxygen isotopes and assemblage composition at Lake Emanda. Quaternary Science Reviews 259: 106905. doi: 10.1016/j.quascirev.2021.106905
Kostrova S.S., Meyer H., Bailey H.L. et al. 2019. Holocene hydrological variability of Lake Ladoga, northwest Russia as inferred from diatom oxygen isotopes. Boreas 48: 361-376. doi: 10.1111/bor.12385
Subetto D.A., Nazarova L.B., Pestryakova L.A. et al. 2017. Palaeolimnological studies in Russian Northern Eurasia: a review. Contemporary Problems of Ecology 4: 327-335. doi: 10.1134/S1995425517040102
Swann G.E.A., Leng M.J., Juschus O. et al. 2010. A combined oxygen and silicon diatom isotope record of Late Quaternary change in Lake El’gygytgyn, North East Siberia. Quaternary Science Reviews 29: 774-786. doi: 10.1016/j.quascirev.2009.11.024
Swann G.E.A., Leng M.J. 2009. A review of diatom δ18O in palaeoceanography. Quaternary Science Reviews 28: 384-398. doi: 10.1016/j.quascirev.2008.11.002

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