Reconstruction of warm-season temperatures in central Europe during the past 60 000 years from lacustrine branched glycerol dialkyl glycerol tetraethers (brGDGTs)

Climate of the past, Journal Year: 2024, Volume and Issue: 20(4), P. 841 - 864

Published: April 8, 2024

Abstract. Millennial-scale climate variations during the last glacial period, such as Dansgaard–Oeschger (DO) cycles and Heinrich events, have been extensively studied using ice core marine proxy records. However, there is a limited understanding of magnitude these temperature fluctuations in continental regions, questions remain about seasonal signal events. This study presents 60 000-year-long reconstruction based on branched glycerol dialkyl tetraethers (brGDGTs) extracted from lake sediments Eifel Volcanic Field, Germany. brGDGTs are bacterial membrane-spanning lipids that known to strong relationship with temperature, making them suitable for reconstructions. We test several calibration models modern samples taken soils multiple maar lakes. find negative bias brGDGT-based estimates associated water depth anoxic conditions can be corrected by accounting brGDGT isomer only produced conditions. The correlates model spanning same time validating approach we selected. millennial-scale variability significantly dampened record, contrast other Northern Hemisphere records, stadials, temperatures actually increase. demonstrate apparent discrepancies explained unique response paleothermometer months above freezing (TMAF). Our data support view warm-season Europe varied minimally period abrupt events were defined colder, longer winters. continuous high-resolution provides important information used inform studies paleoecological change.

Language: Английский

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Disentangling Effects of Sea Surface Temperature and Water Depth on Hydroxylated Isoprenoid GDGTs: Insights From the Hadal Zone and Global Sediments

Geophysical Research Letters, Journal Year: 2023, Volume and Issue: 50(15)

Published: Aug. 8, 2023

Abstract Hydroxylated isoprenoid glycerol dialkyl tetraethers (OH‐GDGTs) preserved in marine sediments are thought to be controlled by sea surface temperature (SST). However, water depth may also exert a significant influence on OH‐GDGTs. Here, we investigated sedimentary OH‐GDGTs the Kermadec and Atacama trench regions (2,560–9,560 m depth). Sedimentary hadal trenches were dominated OH‐GDGT‐0 (72 ± 8%), potentially reflecting an adaption of source organisms ambient cold deep water. This result, combined with global data set, revealed that predominance is ubiquitous phenomenon deep‐sea sediments, leading considerable underestimation RI‐OH′‐derived SSTs. By considering both SST effects, developed more accurate OH‐GDGT‐based paleothermometers for shallow ocean, encompassing full‐ocean‐depth range. Our findings highlight importance accounting effect provide improved tools reconstructing paleo‐SSTs.

Language: Английский

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A 10Be chronology of the Esmark Moraine and Lysefjorden region, southwestern Norway: Evidence for coeval glacier resurgence in both polar hemispheres during the Antarctic Cold Reversal

Quaternary Science Reviews, Journal Year: 2023, Volume and Issue: 316, P. 108259 - 108259

Published: Aug. 26, 2023

Language: Английский

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Evaluating isoprenoidal hydroxylated GDGT-based temperature proxies in surface sediments from the global ocean

Geochimica et Cosmochimica Acta, Journal Year: 2023, Volume and Issue: 370, P. 113 - 127

Published: Dec. 19, 2023

Recently developed temperature proxies based on hydroxylated isoprenoid Glycerol Dialkyl Tetraethers (OH-isoGDGTs), such as %OH, RI-OH, RI-OH′ and OHC, have shown potential for reconstructing past changes. However, progress has been limited by the lack of a global core-top calibration with ample geographical coverage. Here, we compile an extensive surface sediment dataset OH-isoGDGTs well regular GDGTs (isoGDGTs), both data generated at NIOZ (n = 575) previously published from other laboratories 297). We find interlaboratory differences proxy indices that incorporate isoGDGTs, indicating care must be taken in compiling large GDGT datasets multiple laboratories. Our results confirm strong signal isoGDGT distribution, especially OH-isoGDGT-0 non-hydroxylated but also reveal water depth might impact distribution 1 2 cyclopentane moieties. This will affect RI-OH indices, particularly tropical regions, where occurs low abundance. explore new combine dependence OH-isoGDGT distributions propose use TEX86OH, which includes denominator TEX86 index. modification leads to much higher sensitivity index, regions annual mean sea temperatures between 5 15 °C. Application this novel paleothermometer polar core suggests is likely result more reliable reconstructions are abundant.

Language: Английский

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Summer warming during Heinrich Stadial 1 in Northeast China

Geology, Journal Year: 2024, Volume and Issue: 52(6), P. 385 - 389

Published: Feb. 26, 2024

Abstract The last deglaciation is considered a key period for exploring the underlying dynamics of temperature changes because it was characterized by multiple millennial-scale abrupt climatic events. However, limited number quantitative records in Northeast (NE) China covering hampers complete understanding mechanisms and processes behind that occurred region. Here, we present reconstruction summer over based on bacterial branched glycerol dialkyl tetraethers (brGDGTs) analyzed from sediment sequence Lake Kielguo, small volcanic lake NE China. results show lowest during interval ca. 20–18.2 calibrated (cal.) k.y. B.P. with value ~11.1 °C increased ~1.9 Heinrich Stadial 1 (HS1) ~2.7 transition to Bølling-Allerød (B-A). temperatures B-A warm Younger Dryas cold were ~14.1 ~12.0 °C, respectively. record Kielguo indicates warming dominated climate change state HS1 East Asia, which different cooling pattern controlled winter North Atlantic Greenland realms. This distinction can be explained weakened signals triggered collapse Meridional Overturning Circulation when these propagated orbital greenhouse gases Asia.

Language: Английский

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Archaeal Hydroxylated Isoprenoid GDGTs in Asian Lake Sediments: A New Tool for Terrestrial Paleotemperature Reconstructions

Geophysical Research Letters, Journal Year: 2024, Volume and Issue: 51(6)

Published: March 18, 2024

Abstract Hydroxylated isoprenoid GDGTs (OH‐GDGTs) have emerged as a novel tool for reconstructing sea surface temperatures. However, when using marine OH‐GDGT calibration in lacustrine settings, it leads to significant overestimation of temperatures, emphasizing the necessity thorough examination OH‐GDGTs lakes. Here, we investigated distributions sediments from 65 lakes West China and compiled published Asian lake global data sets. Among all GDGT‐based indices, RI‐OH showed strongest correlation with temperature across The value was higher than sediments, likely due differences composition Group 1.1a thaumarchaeotal species between two settings. first developed addressed issue applied both water column sediment core, highlighting potential new terrestrial paleothermometer.

Language: Английский

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The evolutionary history of the field vole species complex revealed by modern and ancient genomes

Research Square (Research Square), Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 10, 2025

Background The field vole, an abundant and widespread microtine rodent, is a complex comprising three cryptic species. short-tailed vole (Microtus agrestis) present over much of Eurasia, the Mediterranean lavernedii) in southern Europe, Portuguese rozianus) limited to western Spain Portugal. Previous research has shown high genomic differentiation these lineages; however, details process underlying their divergence remain unknown. Results We analysed 46 mitogenomes 16 nuclear genomes modern specimens, 75 12 ancient specimens spanning last thousand years, investigate evolutionary history this species complex. estimated from voles be ca. 220 ka ago latter 110 ago, earlier than previous estimates involving only sequences. times we obtained match those between major mitochondrial lineages cold-adapted steppe rodents Europe. found signatures gene flow within lineages, with some analyses suggesting hybrid origin lineage. Ancient Italian Peninsula revealed previously unrecognised lineage that showed evidence genetic exchange other populations. Conclusions pattern variation demonstrates unequivocally impact stadial-interstadial cycles generating recurrent episodes allopatry connectivity populations, situation which could by our dense sampling time.

Language: Английский

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Millennial-scale climate variability of the Asian summer monsoon over the last 690,000 years: insights from cave records

Science Bulletin, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 1, 2025

Language: Английский

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Impact of terrestrial organic matter input on distributions of hydroxylated isoprenoidal GDGTs in marine sediments: Implications for OH-isoGDGT-based temperature proxies

Organic Geochemistry, Journal Year: 2025, Volume and Issue: unknown, P. 105010 - 105010

Published: April 1, 2025

Language: Английский

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Vegetation and climate changes during the Middle to Upper Palaeolithic transition in the southwestern Mediterranean: What happened to the last Neanderthals during Heinrich stadial 4?

Quaternary Science Reviews, Journal Year: 2025, Volume and Issue: 359, P. 109345 - 109345

Published: April 28, 2025

Language: Английский

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