Temperature and nutrients control the presence and distribution of long-chain diols in Swiss lakes DOI Creative Commons
Julie Lattaud, Céline Martin, Ronald Lloren

et al.

Frontiers in Earth Science, Journal Year: 2024, Volume and Issue: 12

Published: June 3, 2024

Long-chain diols are biomarkers commonly used in the marine realm to reconstruct several environmental parameters such as sea surface temperature and salinity. However, they also produced lacustrine slow-flowing river environments, a characteristic that has proved be useful trace past riverine inputs coastal sedimentary records. So far, their use settings is sparse controls not well-known. Previous studies two lakes have shown long-chain diol distribution linked changes (in small Spanish alpine lake), but water column stratification large deep Swiss lake). To understand on i) presence of lakes, ii) isomers, sediments from 52 were studied. present 57% machine learning (i.e., random forest model) showed mainly controlled by mean annual air temperature, sodium potassium concentrations area lakes. isomer relative seems react nutrient (here nitrate) oxygen This new insight was tested short core Lake Zurich, compared with other biomarker proxies (based branched isoprenoid glycerol dialkyl tetraethers), well historical record contents temperature. Variations index (LDI) mirror measured reacted nutrients oxygenation lake. study highlights potential proxy both potentially geological timescales.

Language: Английский

Reconstructing warm-season temperatures using brGDGTs and assessing biases in Holocene temperature records in northern Fennoscandia DOI Creative Commons
Gerard A. Otiniano, Trevor J. Porter, Michael A. Phillips

et al.

Quaternary Science Reviews, Journal Year: 2024, Volume and Issue: 329, P. 108555 - 108555

Published: March 5, 2024

Understanding Holocene climate variability is crucial for predicting future change, which will disproportionally affect high-latitude regions. Summer temperature (Tsummer) reconstructions in regions such as northern Finland are mainly derived from microfossil data. We reconstructed Tsummer spanning the interval 10-1 cal ka BP using branched glycerol dialkyl tetraethers (brGDGTs) lake-sediment record Lake Annan Juomusjärvi (AJU) Finland. The reconstruction shows cool early conditions, ∼2 °C below long-term mean (defined by last 8.5 kyr), followed persistent warming to a thermal maximum around ∼7.0 BP, relatively stable (∼0.5 above mean) 7.0 3.5 and then cooling trend (−0.1 °C·kyr−1) since BP. This history remarkably well replicated nearby pollen-TJuly Loitsana. However, Loitsana chironomid macrofossil data argue much earlier at ∼10 Comparison of versus pollen records across Fennoscandia confirms this inter-proxy discrepancy on timing peak warmth regional-scale phenomenon. Previous studies had raised possibility that non-climatic noise certain records, due local-scale overrepresentation types mid Holocene, may be contributing an artificial lag maximum. brGDGTs unaffected terrestrial flora corroborate mid-Holocene maximum, challenges notion generally prone misrepresenting history. Alternatively, proxy-specific environmental or seasonality biases explain discrepancies warmth. Continued diversification proxy network help better understand differences refine knowledge Fennoscandia.

Language: Английский

Citations

5
New global lacustrine brGDGTs temperature calibrations based on machine learning DOI Creative Commons
Zeyang Zhu, Jing Wu, Guoqiang Chu

et al.

Quaternary Science Reviews, Journal Year: 2025, Volume and Issue: 357, P. 109319 - 109319

Published: March 26, 2025

Language: Английский

Citations

0
Distribution of branched glycerol dialkyl glycerol tetraether (brGDGT) lipids from soils and sediments from the same watershed are distinct regionally (central Chile) but not globally DOI Creative Commons
Molly D. O’Beirne,

Wesley Scott,

Sergio Contreras

et al.

Frontiers in Earth Science, Journal Year: 2024, Volume and Issue: 12

Published: April 17, 2024

Quantitative reconstructions of past continental climates are vital for understanding contemporary and climate change. Branched glycerol dialkyl tetraethers (brGDGTs) unique bacterial lipids that have been proposed as universal paleothermometers due to their correlation with temperature in modern settings. Thus, brGDGTs may serve a crucial paleotemperature proxy variations improving regional projections, especially critical but under constrained regions. That said, complications can arise application varying source contributions (e.g., soils vs. peats lacustrine). As such, this study investigates brGDGT distributions Chilean lake surface sediments corresponding watershed determine the sediments. Global datasets were additionally compiled comparison. Distinct lakes indicate minimal bias from soil inputs lacustrine well situ production brGDGTs, which supports use reliable proxies region. The ΣIIIa/ΣIIa ratio, initially promising indicator marine settings, shows global complexities challenging establishment thresholds apportionment. we show ratio be successfully applied Direct comparisons further research discerning sources on scales moving forward. Overall, contributes valuable insights into variability, essential accurate paleoreconstructions.

Language: Английский

Citations

1
Discrepancies in lacustrine bacterial lipid temperature reconstructions explained by microbial ecology DOI Creative Commons
Jie Liang, Manuel Chevalier, Keshao Liu

et al.

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: Dec. 5, 2024

Abstract Bacterial lipid branched glycerol dialkyl tetraethers (brGDGTs) are a valuable tool for reconstructing past temperatures. However, gap remains regarding the influence of bacterial communities on brGDGT profiles. Here, we identified two distinct patterns brGDGTs from surface sediments 38 Tibetan Plateau lakes using an unsupervised clustering technique. Further investigation revealed that salinity and pH significantly change community composition, affecting profiles causing brGDGT-based temperatures to be overestimated by up 2.7 ± 0.7 °C in haloalkaline environments. We subsequently used trained model examine assemblages global lacustrine dataset, confirming applicability our approach. finally applied approach Holocene records Plateau, showing shifts clusters amplified temperature variations over timescales. Our findings demonstrate microbial ecology can robustly diagnose constrain site-specific discrepancies reconstruction.

Language: Английский

Citations

1
Temperature and nutrients control the presence and distribution of long-chain diols in Swiss lakes DOI Creative Commons
Julie Lattaud, Céline Martin, Ronald Lloren

et al.

Frontiers in Earth Science, Journal Year: 2024, Volume and Issue: 12

Published: June 3, 2024

Long-chain diols are biomarkers commonly used in the marine realm to reconstruct several environmental parameters such as sea surface temperature and salinity. However, they also produced lacustrine slow-flowing river environments, a characteristic that has proved be useful trace past riverine inputs coastal sedimentary records. So far, their use settings is sparse controls not well-known. Previous studies two lakes have shown long-chain diol distribution linked changes (in small Spanish alpine lake), but water column stratification large deep Swiss lake). To understand on i) presence of lakes, ii) isomers, sediments from 52 were studied. present 57% machine learning (i.e., random forest model) showed mainly controlled by mean annual air temperature, sodium potassium concentrations area lakes. isomer relative seems react nutrient (here nitrate) oxygen This new insight was tested short core Lake Zurich, compared with other biomarker proxies (based branched isoprenoid glycerol dialkyl tetraethers), well historical record contents temperature. Variations index (LDI) mirror measured reacted nutrients oxygenation lake. study highlights potential proxy both potentially geological timescales.

Language: Английский

Citations

0