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We present data on molluscan fauna within the L3 loess unit (and partially within the S3 paleosol) from the key loess section of Veliki Surduk in Serbia. The section correlates to Marine Isotope Stage (MIS) 8 and late MIS 9 and, thus, spans the time frame from ~350 to 250 ka. The Veliki Surduk loess–paleosol sequence (LPS) is located on the northwestern margin of the Titel loess plateau and comprises ~30 m of sediments. Our focus is on a 5.4 m thick sedimentary interval, which was sampled at 20 cm increments, each sample covering approximately 2 ky. Nine mollusk species were identified in the loess sequence: Granaria frumentum, Helicopsis striata, Pupilla triplicata, Chondrula tridens, Pupilla muscorum, Succinella oblonga, Punctum pygmaeum, Vallonia costata, and Vitrina pellucida, as well as a few unidentified slug taxa (Limacidae, Agriolimacidae, and Milacidae). The majority of the snail assemblage occurs at the transition between MIS 9 and MIS 8, suggesting a mostly dry climate and an open and steppe-like habitat. The fauna identified in the upper part of the paleosol layer S3, below the L3 unit, indicated aridification. [ABSTRACT FROM AUTHOR]

The long-term effects of climate change and climate extremes have been associated with changes in tree growth and forest productivity worldwide, and dendrochronological analyses are important tools that can be used to investigate the influence of climatic forces on tree growth at a particular site. In this study, a 180-year tree ring width chronology (spanning from 1843 to 2022) of living pine trees (Pinus latteri) in Tak province, northwestern Thailand, was developed. The analysis of the climate–tree growth relationship indicated the influences of the annual total rainfall (r = 0.60, p < 0.001) and annual averaged relative humidity (r = 0.47, p < 0.001) on tree growth in this area. Anomalously high (for example, in 1853, 1984, 2011, and 2018) and low growths (for example, in 1954, 1983, 1992, and 1996) were found. Growth anomalies in the Thai pine in this study were related to changes in abnormal and extreme rainfall (r = 0.94, p < 0.001) and the El Niño Southern Oscillation (ENSO). Our results confirm that rainfall and relative humidity are the main climatic factors regulating the radial growth of Thai pine. This finding could be an important contribution to further research on the effects of climate change and extreme weather events on the vulnerability of tropical and subtropical trees in this region. [ABSTRACT FROM AUTHOR]

The reasons for covariations of speleothem δ13C and δ18O remain controversial, primarily due to the limited high‐resolution stalagmite records that can be compared with meteorological data. This study presents δ13C and δ18O records of two coeval, annually laminated stalagmites (TS9701 and TS9501) spanning the past ∼2000 years from Shihua cave, Beijing, northern China. The low correlation between stalagmite TS9701 records, with annual resolution, and local annual precipitation as well as mean annual temperature on interannual to decadal scales indicates that the positive covariations of δ18O and δ13C in TS9701 are partly attributed to kinetic isotope effects caused by rapid CO2 degassing. Isotopic disequilibrium between HCO3−(aq) and drip water, induced by prior calcite precipitation on cave ceiling and stalactite surface, is another potential contributing factor. δ18O and δ13C exhibits distinct patterns on multidecadal to millennial timescales. δ18O records show notable centennial variability, aligning with El Niño‐Southern Oscillation cycles. In contrast, δ13C profiles reveal a decreasing trend during the first ∼750 years, followed by an increasing trend. Prior to 1588 AD, variations in δ13C broadly correspond to changes in warm season temperature and/or moisture on centennial scale. Both δ13C records show an abrupt enrichment between 1588 and 1654 AD. Historical documents indicate that this anomaly is likely attributed to coal mining and resultant deforestation around Shihua cave during late‐Ming and early‐Qing Dynasties. In summary, while isotopic disequilibrium can cause high‐frequency covariations of speleothem δ18O and δ13C, it does not erase the imprints of climate changes and human activities on multidecadal to millennial timescales. Plain Language Summary: This study examines the relationship between δ13C and δ18O of stalagmites from Beijing, northern China. We analyzed two stalagmites, TS9701 and TS9501, which grew over the past ∼2000 years. We found that the covariations in δ13C and δ18O on interannual to decadal scales do not directly correspond to local annual rainfall or temperature changes. Instead, these variations are partly caused by isotopic disequilibrium due to prior calcite precipitation on the cave ceiling and stalactite surface as well as rapid CO2 degassing during stalagmite grew. However, δ18O and δ13C exhibit distinct patterns on multidecadal to millennial timescales. δ18O records show significant centennial variability, linked to El Niño‐Southern Oscillation cycles. δ13C records reveal a decreasing trend during the first ∼750 years, followed by an increasing trend. Before 1588 AD, variations in δ13C broadly matched changes in warm season temperature and/or moisture on centennial scale. Between 1588 and 1654 AD, δ13C records show a sudden increase, likely due to coal mining and the resulting deforestation around the cave during late‐Ming and early‐Qing Dynasties. In summary, while isotopic disequilibrium can cause high‐frequency variations in stalagmite isotopes, it does not erase the effects of climate changes and human activities over longer timescales. Key Points: Correlation between δ18O and δ13C in a laminated stalagmite from northern China varies across multi‐timescalesInterannual to decadal covariations of stalagmite δ18O and δ13C partly result from isotopic disequilibrium as prior loss of 12C16O2Isotopic disequilibrium does not alter multidecadal to millennial isotopic variations in response to climate changes and human activities [ABSTRACT FROM AUTHOR]

We present a new teak (Tectona grandis L.f.) tree-ring stable oxygen isotope (δ18OTR) chronology from Mae Tuen (MT) site, Tak province, northwestern Thailand at inter-annual (167-year, A.D.1850–2016) and intra-annual (A.D.2006–2016) timescales. The inter-annual δ18OTR chronology showed a significant negative correlation (r = −0.678, p < 0.01) with the May–October amount of regional rainfall obtained from CRU TS4.03. We established a linear regression model that explained 46.0% of the actual rainfall variance and reconstructed monsoon season rainfall back to A.D.1850. The seasonal variations in moisture conditions were reflected in inter-annual δ18OTR variability. The rainfall amount and δ18O in precipitation (δ18Op) mainly controlled intra-annual variations in teak δ18OTR. These results show that the variation in Thai teak δ18OTR is dominated by rainfall, highlighting the strength of δ18OTR as a monsoon rainfall proxy. [ABSTRACT FROM AUTHOR]

Thailand monsoon is located in the transition zone between the Indian and western North Pacific monsoons. Assuredly, proxy climate data from this area could improve our understanding of the nature of Asian monsoon. Tree rings and stalagmites from this area are two potential materials for high-resolution paleoclimate reconstructions. However, a comprehensive understanding of these multiproxy records is still a challenge. In this study, a 76-year tree ring cellulose oxygen isotope value (δ18O) of a teak tree from northwestern Thailand was developed to test its climatic significance and potential for multiproxy climate reconstruction. The results indicate that the interannual variability of cellulose δ18O can be interpreted as a proxy of rainfall in the early monsoon season (May to July rainfall) as well as a proxy of relative humidity. Comparisons with speleothem proxies from the same locality and tree ring records from wider geographical areas provide a basis for developing a multiproxy approach. The results from a teleconnection analysis reveal that the El Niño-Southern Oscillation (ENSO) is an important climate mode that impacts monsoon rainfall in Thailand. High-quality proxy records covering recent decades are critically important not only to improve proxy data calibrations but also to provide a better understanding of teleconnections within the modern atmosphere. Preliminary findings demonstrated the potential of tree ring stable isotopes from Thai teak to develop multiproxy climate reconstruction. [ABSTRACT FROM AUTHOR]

Thailand has been regarded as a transition zone between the Indian and western North Pacific monsoons which produce most of the precipitation in this area and sustain large-scale agricultural activities. Their different moisture sources and associated transport trajectories could result in distinguishable seasonal variations in rainfall oxygen isotopes (δ18O). Knowledge about seasonal variability in Thailand monsoon could facilitate agricultural water management and improve our understanding of the Asian monsoon system. In this study, a detailed examination of the intra-seasonal variability of tree-ring cellulose δ18O in teak trees from Northwestern Thailand was performed. The results show clear intra-seasonal variability in cellulose δ18O, with heavier values in the early rainy season and much lighter values in the later rainy season. Climate correlation analysis indicates that there is a significant and positive correlation between sub-seasonal variation in cellulose δ18O and rainfall δ18O. A weak and negative correlation with relative humidity (RH) has also been identified. However, there is no relation between intra-seasonal variation in cellulose and that of the amount of rainfall. These results imply that intra-seasonal variability of cellulose δ18O in teak trees from Northwestern Thailand may inherit such variability in rainfall δ18O and might be slightly shaded by RH. The spatial correlations with large-scale precipitation in the Merged Analysis (CMAP) and Outgoing Longwave Radiation (OLR) data sets indicated seasonal changes in moisture origin and may potentially be used to explore long-term monsoon climate variability on a seasonal scale in subtropical Southeast Asia. [ABSTRACT FROM AUTHOR]