Digging deeper and deeper into the Lake Chany basin

Lake Chany in Western Siberia has historically been a shallow lake, approximately 2 metres deep and a 2.2 thousand km2 area. It is saline which is similar to other lakes in the region due to intensive evaporation after rain and run off. This theoretically increases the affect of climate change in water levels and surrounding ecosystems. Lake water supports nearby agriculture and industrial fisheries. As we move out of the Holecene era, researchers wished to study changes in the basin and estimate future climate impacts. It has previously been affected by both drought and flooding.

The mean annual air temperature is about zero (+19 ℃ in July and –19 ℃ in January); the warm period in terms of mean monthly temperatures is seven months and in terms of solar radiation balance is eight months per year. Continentality leads to abrupt fluctuations and high temperature ranges during a year; the recorded absolute values are + 38 ℃ in July and −48 ℃ in January. The mean annual precipitation is 300–450 mm/yr. with maximum in the summer months. The potential evaporation is 400–550 mm/yr.

(Krivonogov et al, 2023, https://doi.org/10.1016/j.gsf.2022.101518 )

There are detailed historical records and sediment archives. They obtained data by drilling into Yarkov and Yudin sub-basins , and the Malye Chany lake. They took four sediment cores, pollen cores and reviewed the stratigraphy. Analysis of their biological, geochemical, paleontological and mineralogical core data presented a different picture to the existing historical evidence of the basin. They found an average depth of 3.1 metres on average in the Yarkov sub-basin. There was less impact from waves on the lake floor sediment.

Fig. 3. Stratigraphy and proportions of main sediment components in Yarkov-02 core.

There are a mix of arid and wet soils and the salinity volume affects swamp development, peat mass and quality. There is a high saline impact overall on soil quality in the basin. Surrounding vegetation includes steppes, ‘kolki’ (groves), meadows and water meadows. There are a mix of biomes but the researchers also found an increase in desertification in some areas.

Overall, the Chany lake has become deeper and increasingly saline, despite the greater water volume during the Holocene era. However they found less correlation with warmer and colder events caused by climatic changes. They believe the increase in lake volumes with surrounding wetter soils and vegetation succession that changes the forest steppe had a greater impact. Some of the lakes in the southern basin have not yet been investigated in greater detail.

S.K. Krivonogov, A.N. Zhdanova, P.A. Solotchin, A.Y. Kazansky, V.V. Chegis, Z. Liu, M. Song, S.V. Zhilich, N.A. Rudaya, X. Cao, O.V. Palagushkina, L.B. Nazarova, L.S. Syrykh, (2023), The Holocene environmental changes revealed from the sediments of the Yarkov sub-basin of Lake Chany, south-western Siberia, Geoscience Frontiers, 14:2, https://doi.org/10.1016/j.gsf.2022.101518

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