Towards the Third Millennium Changes in Siberian Triple Tree-Ring Stable Isotopes

Abstract

Significant air temperature and precipitation changes have occurred since the 2000s in vulnerable Siberian subarctic regions and urged updates of available chronologies towards the third millennium. It is important to better understand recent climatic changes compared to the past decades, centuries and even millennia. In this study, we present the first annually resolved triple tree-ring isotope dataset (δ13C, δ18O and δ2H) for the eastern part of the Taimyr Peninsula (TAY) and northeastern Yakutia (YAK) from 1900 to 2021. We found that the novel and largely unexplored δ2H of larch tree-ring cellulose was linked significantly with δ18O for the YAK site, which was affected by averaged April–June air temperatures and evaporation. Simulated by the Land Surface Processes and Exchanges (LPX-Bern 1.0) model, the water fraction per year for soil depths at 0–20 and 20–30 cm was significantly linked with the new eco-hydrological tree-ring δ2H data. Our results suggest increasing evapotranspiration and response of trees’ water relation to rising thaw water uptake from lower (20–30 cm) soil depth. A positive effect of July air temperature on tree-ring δ18O and a negative impact of July precipitation were found, indicating dry conditions. The δ13C in larch tree-ring cellulose for both sites showed negative correlations with July precipitation and relative humidity, confirming dry environmental conditions towards the third millennium.

Dual Carbon and Oxygen Isotopes in Siberian Tree Rings as Indicator of Millennia Sunshine Duration Changes

“…The average tree-ring width (TRW) of living trees ranges from 0.15 to 0.26 mm, while for dead trees it ranges between 0.26 and 0.29 mm. Tree cores and discs from living larch trees and dead trunks were collected within 69 -70 • N and 139-148 • E during several expeditions (Hughes et al, 1999;Sidorova et al, 2008;Churakova (Sidorova) et al, 2016, 2023, Churakova et al, 2022a, 2022b) from 1994 to 2020 CE.…”

Climate impacts on tree-ring stable isotopes across the Northern Hemispheric boreal zone

“…Intra-annual climate variability is high for the subarctic region. Highly continental boreal sites experience an extreme range of air temperature characterized by harsh winters, with daily minimum -55 °C and annual average temperature -14 °C in Yakutia and rather short (up to 70-90 days) and hot summers, with daily maximum temperature, which can reach +45 °C and mean annual air temperature of 1.2 °C in Siberian transect at the southern boreal region in Khakassia (KHAK, Table 1), e.g., Köppen zones Dfc and Dwc, Abaimov et al, 1997;Knorre et al, 2006Boike et al, 2013;Churakova (Sidorova) et al, 2022a, 2022b. The sum of annual precipitation varies across high-latitudinal sites from 205 mm in eastern part up to 2035 mm /year in the western part of subarctic (Table 1).…”

“…Sunshine duration and cloud cover are rather variable across boreal regions. In summer, sunshine duration lasts longer at high latitudes than at the southern taiga and forest steppe zone (Young et al, 2012;Gagen et al, 2016;Churakova (Sidorova) et al, 2019, 2022a, 2022bChurakova-Sidorova et al, 2022).…”

“…These input waters to the soil are modified in the soil by enrichment in 18 O as a result of evaporation and in the leaf during transpiration, which is imprinted as a combined isotope signal on photosynthates and cellulose through biochemical fractionation and exchange processes (Roden et al, 2000;Barbour, 2007). In Siberia, the inter-annual variability of winter precipitation δ 18 O is closely related to temperature variability and the Arctic and North Atlantic Oscillation (Sidorova et al, 2011;, 2022a, while the variability of summer δ 18 O appears to be dominated by regional processes involving evaporation and convection (Butzin et al, 2014). Therefore, δ 18 O values of tree rings reflect, as a first approximation, average cloud condensation temperatures (Dansgaard, 1964), water origin, cloud cover and showing teleconnection with atmospheric circulation patterns via precipitation, evaporation and condensation processes in the global water cycle (Konecky et al, 2020(Konecky et al, , 2023.…”

“…The use of hydrogen isotopes (δ 2 H) in precipitation samples have been studied at a global scale and broadly correlate with mean global temperature (Dansgaard, 1964;Konecky et al, 2020). However, only few studies have examined the potential use δ 2 H in tree rings as a paleoenvironmental proxy (Roden et al, 2000;Hilasvuori, 2011;Voelker et al, 2014;Kimak and Leuenberger, 2015;Arosio et al, 2021;Lehmann et al, 2021;Schuler et al, 2022;Churakova Sidorova et al, 2022a). Recent studies showed that δ 2 H in tree-ring cellulose (δ 2 H trc ) is more than a temperature proxy and can contain information about biochemical processes related to photosynthesis and ecohydrological changes (Lehmann et al, 2021;Schuler et al, 2022).…”