Article
Geochemistry & Geophysics
Molly D. O'Beirne, Wesley P. Scott, Josef P. Werne
Summary: Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are membrane-spanning lipids produced by bacteria that are ubiquitous in natural sedimentary archives and preserved over geologic timescales. They can serve as a powerful proxy for paleotemperature reconstruction, but recent studies have shown the need for regional temperature calibration models. In this study, we analyzed lake sediment samples from across the globe and identified significant clusters of brGDGT distributions. We developed cluster-specific temperature models and a cluster prediction model with high accuracy. Applying this approach to published lacustrine records, we highlighted the limitations and pitfalls of brGDGT-based temperature reconstructions.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geography, Physical
Tae Wook Ko, Kyung Eun Lee, Masanobu Yamamoto, Dongseon Kim
Summary: The spatial and temporal distributions of GDGT concentrations in suspended materials were investigated in the northern East China Sea to assess the potential use of GDGT-based TEX86 as a proxy for annual mean sea surface temperature (SST). The study found significant differences between TEX86 temperatures and in situ temperatures, indicating the limitations of using TEX86 as a proxy for SST in the study area. The presence of high GDGT concentrations near the bottom suggests sediment resuspension and transportation in the western part of the area, while maximum GDGT concentrations in the eastern part were found in the subsurface layer at depths of 20-50 m.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2022)
Review
Ecology
Jingjie Zang, Huan Yang, Jiahao Zhang, Huiru Tang, Liangcheng Tan
Summary: Glycerol dialkyl glycerol tetraethers (GDGTs), derived from microbial membranes, are widely found in various environments such as soils, lake sediments, and hot springs. They have become an important tool in paleoenvironmental reconstruction due to their sensitivity to environmental changes. However, their application in speleothems, an important archive for studying past climates, has been limited. This paper reviews recent progress in the study of GDGTs in speleothems, including their sources, distribution characteristics, and paleoenvironmental applications. The proxies based on GDGTs show promising potential for reconstructing terrestrial paleotemperature.
FRONTIERS IN ECOLOGY AND EVOLUTION
(2023)
Article
Environmental Sciences
Mustafa Alirezazadeh, Mohammad Javad Nematollahi, Behnam Keshavarzi, Mohsen Rezaei, Farid Moore, Rosa Busquets
Summary: This study evaluated the status of microplastics in abiotic compartments of saline Maharloo Lake in Iran for the first time. The results showed that microplastics mainly originated from potential plastic sources in the urban areas and industrial zone near the lake, and were dispersed into the lake through surface runoff.
ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY
(2023)
Review
Geography, Physical
Boyang Zhao, James M. Russell, Victor C. Tsai, Ansis Blaus, Meredith C. Parish, Jie Liang, Alexander Wilk, Xiaojing Du, Mark B. Bush
Summary: Branched glycerol dialkyl glycerol tetraethers (brGDGTs) preserved in lake sediments are widely used to study past terrestrial temperatures. The distribution of brGDGTs is influenced by temperature, and current calibration methods rely on correlations with surface sediments. However, these methods may introduce complications in global temperature calibrations due to differences in temperature seasonality and brGDGT production with latitude. This study examines brGDGT data from tropical regions and finds a uniform response to mean annual air temperature, highlighting the dominant influence of temperature. Moreover, the study suggests the need for latitudinally-dependent calibrations or improved observations/models to account for seasonal effects on brGDGTs.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
Yu-Hyeon Park, Boo-Keun Khim
Summary: In this study, seawater temperatures in the Hupo Trough influenced by the East Korea Warm Current (EKWC) were estimated using U(37)(K') and TEX86 data. The applicability of the TEX86 paleothermometer in reconstructing the EKWC temperature variability since the Last Glacial Maximum (LGM) was tested. The results showed that the EKWC has been relatively stable since the mid-Holocene, with slight fluctuations during the late Holocene. The temperature change of the EKWC seems to be closely linked to global/regional climate variability.
ORGANIC GEOCHEMISTRY
(2022)
Article
Environmental Sciences
Mingfei Chen, Jessica L. Conroy, Robert A. Sanford, Joanne C. Chee-Sanford, Lynn M. Connor
Summary: This study examines the relationship between lake sedimentary δ-15N values and microbiome profiles, revealing that specific microbial processes such as denitrification influence the δ-15N signatures in lake sediment records. Metagenomics analysis provides clarity on the microbial activities that contribute to variations in δ-15N values, shedding light on the nitrogen cycle dynamics in lacustrine systems. The high δ-15N values in surface sediments are likely due to denitrification processes, while low values in deeper sediments are associated with assimilatory nitrate reduction and ammonification processes.
JOURNAL OF PALEOLIMNOLOGY
(2021)
Article
Geochemistry & Geophysics
C. De Jonge, E. E. Kuramae, D. Radujkovic, J. T. Weedon, I. A. Janssens, F. Peterse
Summary: The soil pH has a significant impact on the distribution of branched glycerol dialkyl glycerol tetraethers (BrGDGTs) and bacterial community composition. Changes in soil pH lead to variations in the MBT'(5ME) values, highlighting the importance of considering pH changes in paleoclimate studies.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Christoph Haggi, B. David A. Naafs, Daniele Silvestro, Dailson J. Bertassoli Jr, Thomas K. Akabane, Vinicius R. Mendes, Andre O. Sawakuchi, Cristiano M. Chiessi, Carlos A. Jaramillo, Sarah J. Feakins
Summary: This study surveys the distribution of brGDGT and isoGDGT in tropical South America and establishes new brGDGT-based temperature models. The results show variations in the distribution of these lipids in different soil types and profiles, and provide insights for paleoclimatic reconstructions.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Biochemistry & Molecular Biology
Alka Rao, Niels A. W. de Kok, Arnold J. M. Driessen
Summary: Cellular membranes play essential roles in compartmentalization, permeability maintenance, and fluidity in all three domains of life. Archaea, as the third domain of life, have unique phospholipid compositions. The study focuses on Sulfolobus acidocaldarius, an archaeon with a membrane dominated by glycerol dialkyl glycerol tetraethers (GDGTs), and the effects of the antifungal terbinafine on its lipidome and transcriptome. The results show that terbinafine treatment leads to growth phase-dependent depletion of GDGTs and the accumulation of bilayer-forming dialkyl glycerol diethers (DGDs). Transcriptomic analysis reveals significant differential expression of genes involved in respiratory stress, isoprenoid biosynthesis, and saturation. Overall, terbinafine inhibition affects the respiratory complex, motility, cell envelope, fatty acid metabolism, and GDGT cyclization in S. acidocaldarius.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2023)
Article
Materials Science, Multidisciplinary
Sevan Goenezen, Baik Jin Kim, Maulik Kotecha, Ping Luo, Mohammad R. Hematiyan
Summary: This paper introduces a novel tomography approach based on the mechanics of solids, successfully validated through experiments. The method utilizes equilibrium equations and an optimization framework to control the ill-posed nature of the problems. The study demonstrates the potential of this method on composite silicone material, while also encouraging its use as a breast tumor screening tool.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Chemistry, Multidisciplinary
Yue Zhou, Lingwen Liao, Shengli Zhuang, Yan Zhao, Zibao Gan, Wanmiao Gu, Jin Li, Haiteng Deng, Nan Xia, Zhikun Wu
Summary: Removing or adding kernel atoms of metal nanoclusters without leaving a trace is a challenge, but crucial for improving properties and understanding the kernel-property correlation. The study achieved traceless removal of two kernel atoms in a gold nanocluster and demonstrated that the kernel Au-Au bond length can be used as an indicator for comparing photoluminescence or kernel charge state in similar nanoclusters.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Environmental Sciences
Yuan Qi, Lixin Wu, Yifan Ding, Yingjia Liu, Xiao Wang, Wenfei Mao
Summary: This study focused on the spatiotemporal variations of microwave brightness temperature (MBT) in the Bayan Har block on the Qinghai-Tibet Plateau in China. The results showed a negative correlation between MBT and regional altitude, as well as different response characteristics to soil and vegetation properties. The study also discovered that MBT anomalies preceding two earthquakes in the Bayan Har block could potentially serve as precursors. This research has important implications for studying seismic MBT anomalies on the Qinghai-Tibet Plateau.
Article
Multidisciplinary Sciences
Shai Adar-Levor, Dikla Nachmias, Shani T. Gal-Oz, Yarden M. Jahn, Nadine Peyrieras, Assaf Zaritsky, Ramon Y. Birnbaum, Natalie Elia
Summary: Animal cytokinesis ends with the formation of intercellular bridges that connect sibling cells, ultimately resolved by abscission. In early zebrafish development, delayed abscission leads to interconnected cell clusters during rapid division cycles, while acceleration of abscission occurs during the midblastula transition (MBT). Components of the ESCRT machinery enriched at intercellular bridges post-MBT suggest a role in driving abscission and influencing cell behavior coordination during embryonic development.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Geochemistry & Geophysics
Zhangyu Cheng, Fengling Yu, Nengwang Chen, Huan Yang, Xiaoyan Ruan, Shuqin Tao, Zhaoquan Huang
Summary: This study investigates the correlation between brGDGT-based indices and modern environmental parameters, and discusses the impact factors. The results show that CBT' and IR(x') indices are useful for pH reconstruction, while the MBT'(5ME) index is sensitive to air temperature. Additionally, complex aquatic biogeochemical conditions and the source of brGDGTs significantly influence the indices.
Article
Biochemical Research Methods
Sabine K. Lengger, Yuki Weber, Kyle W. R. Taylor, Sebastian H. Kopf, Robert Berstan, Ian D. Bull, Jan-Peter Mayser, William D. Leavitt, Jerome Blewett, Ann Pearson, Richard D. Pancost
Summary: The study presents a method to determine the hydrogen isotopic composition of lipids using high-temperature gas chromatography on a modified GC/P/IRMS system. The results show that the method is suitable for determining the δH-2 values of various high molecular weight compounds such as TGs and GDGTs, expanding the possibilities for biomarker and food stable isotope analyses. Initial measurements suggest that bacterial and archaeal GDGT δH-2 values may reflect environmental and ecological conditions.
RAPID COMMUNICATIONS IN MASS SPECTROMETRY
(2021)
Article
Geology
Gordon N. Inglis, Megan Rohrssen, Elizabeth M. Kennedy, Erica M. Crouch, J. Ian Raine, Dominic P. Strogen, B. David A. Naafs, Margaret E. Collinson, Richard D. Pancost
Summary: Evidence suggests that during the onset of the PETM, there was a significant disruption in the methane cycle with increased consumption of methane, leading to higher temperatures. Despite elevated temperatures, the methane cycle operated differently during transient warming events compared to gradual warming events in the early Eocene.
Correction
Environmental Sciences
J. Loisel, A. V. Gallego-Sala, M. J. Amesbury, G. Magnan, G. Anshari, D. W. Beilman, J. C. Benavides, J. Blewett, P. Camill, D. J. Charman, S. Chawchai, A. Hedgpeth, T. Kleinen, A. Korhola, D. Large, C. A. Mansilla, J. Muller, S. van Bellen, J. B. West, Z. Yu, J. L. Bubier, M. Garneau, T. Moore, A. B. K. Sannel, S. Page, M. Valiranta, M. Bechtold, V. Brovkin, L. E. S. Cole, J. P. Chanton, T. R. Christensen, M. A. Davies, F. De Vleeschouwer, S. A. Finkelstein, S. Frolking, M. Galka, L. Gandois, N. Girkin, L. I. Harris, A. Heinemeyer, A. M. Hoyt, M. C. Jones, F. Joos, S. Juutinen, K. Kaiser, T. Lacourse, M. Lamentowicz, T. Larmola, J. Leifeld, A. Lohila, A. M. Milner, K. Minkkinen, P. Moss, B. D. A. Naafs, J. Nichols, J. O'Donnell, R. Payne, M. Philben, S. Piilo, A. Quillet, A. S. Ratnayake, T. P. Roland, S. Sjogersten, O. Sonnentag, G. T. Swindles, W. Swinnen, J. Talbot, C. Treat, A. C. Valach, J. Wu
Summary: The correction to this paper has been published.
NATURE CLIMATE CHANGE
(2021)
Article
Environmental Sciences
J. Loisel, A. Gallego-Sala, M. J. Amesbury, G. Magnan, G. Anshari, D. W. Beilman, J. C. Benavides, J. Blewett, P. Camill, D. J. Charman, S. Chawchai, A. Hedgpeth, T. Kleinen, A. Korhola, D. Large, C. A. Mansilla, J. Muller, S. van Bellen, J. B. West, Z. Yu, J. L. Bubier, M. Garneau, T. Moore, A. B. K. Sannel, S. Page, M. Valiranta, M. Bechtold, V Brovkin, L. E. S. Cole, J. P. Chanton, T. R. Christensen, M. A. Davies, F. De Vleeschouwer, S. A. Finkelstein, S. Frolking, M. Galka, L. Gandois, N. Girkin, L. Harris, A. Heinemeyer, A. M. Hoyt, M. C. Jones, F. Joos, S. Juutinen, K. Kaiser, T. Lacourse, M. Lamentowicz, T. Larmola, J. Leifeld, A. Lohila, A. M. Milner, K. Minkkinen, P. Moss, B. D. A. Naafs, J. Nichols, J. O'Donnell, R. Payne, M. Philben, S. Piilo, A. Quillet, A. S. Ratnayake, T. P. Roland, S. Sjogersten, O. Sonnentag, G. T. Swindles, W. Swinnen, J. Talbot, C. Treat, A. C. Valach, J. Wu
Summary: Peatlands are influenced by climate and land use changes, impacting the carbon cycle. While there is a shift predicted from carbon sink to source this century, peatlands are still overlooked in major Earth system models and integrated assessment models for future climate change projections. This study emphasizes the importance of including peatland science in research agendas to better understand the nexus between peatland carbon dynamics and climate change.
NATURE CLIMATE CHANGE
(2021)
Article
Geosciences, Multidisciplinary
Jose M. Castro, Pedro A. Ruiz-Ortiz, Gines A. de Gea, Roque Aguado, Ian Jarvis, Helmut Weissert, Jose M. Molina, Luis M. Nieto, Richard D. Pancost, Maria L. Quijano, Matias Reolid, Peter W. Skelton, Carmina Lopez-Rodriguez, Rafael Martinez-Rodriguez
Summary: This study presents a high-resolution carbonate C-isotope stratigraphy for the Aptian in the Cau core (Spain) and focuses on the early Aptian Oceanic Anoxic Event (OAE 1a). It reveals a record of pulses of volcanism and methane emissions through sharp delta C-13(carb) negative spikes. The C-isotope profile across OAE 1a perfectly records the defined segments worldwide and proposes the Cau core as a new reference section for the Aptian.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Geography, Physical
Marissa A. Davies, Jerome Blewett, B. David A. Naafs, Sarah A. Finkelstein
Summary: The study indicates that hydrological controls at the local scale have a significant impact on peat accumulation during periods of high temperatures in the Holocene. The variation in peat accumulation rate is closely related to the transition of the ecosystem. Bacterial membrane lipid biomarkers, used to infer paleotemperature, can also reflect changes in peat type.
QUATERNARY RESEARCH
(2021)
Article
Geochemistry & Geophysics
Jie Wu, Huan Yang, Richard D. Pancost, B. David A. Naafs, Shi Qian, Xinyue Dang, Huiling Sun, Hongye Pei, Ruicheng Wang, Shijin Zhao, Shucheng Xie
Summary: The distribution of GDGTs varies significantly with bottom water dissolved oxygen concentration in Lake Yangzonghai, reflecting their specific biological sources and environmental controls. Genetic data indicates that changes in GDGT parameters induced by dissolved oxygen are related to shifts in bacterial and archaeal communities across the oxycline in the lake. The MBT ' and MBT '(6ME) brGDGT indices show strong correlations with DO concentration, while the MBT '(5ME) index appears to be more resilient to these impacts, potentially making it more suitable for reconstructing temperature in lake systems.
Article
Biology
B. D. A. Naafs, G. Bianchini, F. M. Monteiro, P. Sanchez-Baracaldo
Summary: The 2-methylhopanes are molecular fossils of 2-methylbacteriohopanepolyols and are among the oldest biomarkers on Earth. Studies show that the gene responsible for their synthesis is widespread in cyanobacteria and proteobacteria, suggesting their dominant presence in these bacterial cultures. Geological records indicate the occurrence of 2-methylhopanes from the Paleoproterozoic onwards, with high abundances associated with climatic and biogeochemical perturbations during the Phanerozoic.
Article
Geosciences, Multidisciplinary
Vittoria Lauretano, Alan T. Kennedy-Asser, Vera A. Korasidis, Malcolm W. Wallace, Paul J. Valdes, Daniel J. Lunt, Richard D. Pancost, B. David A. Naafs
Summary: The study presents a semi-continuous terrestrial temperature record spanning from the middle Eocene to the early Oligocene, using bacterial molecular fossils preserved in lignites from southeast Australia. Results show a gradual decline in mean annual temperatures in southeast Australia, with a step cooling across the Eocene/Oligocene boundary, likely driven by changes in pCO2. Climate model simulations support these findings, indicating the importance of pCO2 decline in influencing temperatures in southeast Australia during this time period.
Article
Geochemistry & Geophysics
B. D. A. Naafs, A. S. F. Oliveira, A. J. Mulholland
Summary: Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are bacterial membrane lipids that are ubiquitous in the environment, and their degree of methylation is correlated with temperature, forming the basis of the brGDGT paleothermometer. Molecular dynamics simulations show that increasing the degree of methylation modulates membrane order and packing, making the membrane less rigid and more fluid. These findings support the hypothesis that the brGDGT paleothermometer is based on homeoviscous adaptation.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Yiming Zhang, B. David A. Naafs, Xianyu Huang, Qingwei Song, Jiantao Xue, Ruicheng Wang, Meiling Zhao, Richard P. Evershed, Richard D. Pancost, Shucheng Xie
Summary: Wetlands play a crucial role in the carbon cycle as the largest natural source of methane, a potent greenhouse gas. Changes in wetland hydrology can significantly impact microbial community structure and carbon metabolic activity, influencing wetland carbon dynamics and greenhouse gas emissions.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
Ana Lucia L. Dauner, B. David A. Naafs, Richard D. Pancost, Cesar C. Martins
Summary: IsoGDGTs are archaeal biomarkers that can be used to reconstruct sea surface temperatures. The TEX86 paleothermometer is widely utilized for this purpose, however its application to polar regions remains limited. This study tested different calibrations for TEX86 in Antarctic coastal sediments and found that a quadratic calibration yielded the best results, indicating the potential for using TEX86 to reconstruct SSTs in the Antarctic coastal region. Sterol biomarkers suggested a dominant marine source of organic matter in the sediments, with seasonal variations in TEX86 signal and differences in compound sources over time.
ORGANIC GEOCHEMISTRY
(2021)
Article
Geochemistry & Geophysics
J. Blewett, F. J. Elling, B. D. A. Naafs, L. Kattein, T. W. Evans, V Lauretano, A. Gallego-Sala, R. D. Pancost, A. Pearson
Summary: This study presents an in-depth analysis of the carbon isotopes of archaeal and bacterial tetraether lipids in the Florida Everglades wetland. The results provide insights into the carbon metabolism of the source organisms and the microbial carbon cycling in wetland sediments. The findings highlight the applicability of tetraether isotope analysis in studying modern and ancient wetland ecosystems.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geosciences, Multidisciplinary
Anya J. Crocker, B. David A. Naafs, Thomas Westerhold, Rachael H. James, Matthew J. Cooper, Ursula Roehl, Richard D. Pancost, Chuang Xuan, Colin P. Osborne, David J. Beerling, Paul A. Wilson
Summary: Records from an ocean core off west Africa show that pulses of Saharan dust have been entering the North Atlantic since at least 11 million years ago, indicating astronomically paced cycles between arid and humid conditions in northern Africa. These findings provide important context for understanding the causes and consequences of regional aridity, as well as the evolutionary outcomes on the African continent.
Article
Geosciences, Multidisciplinary
Christopher J. Hollis, Sebastian Naeher, Christopher D. Clowes, B. David A. Naafs, Richard D. Pancost, Kyle W. R. Taylor, Jenny Dahl, Xun Li, G. Todd Ventura, Richard Sykes
Summary: Late Paleocene deposition of organic-rich sedimentary facies in New Zealand and eastern Australia was caused by climatic cooling and terrestrial denudation. The organic matter in this facies is primarily of terrestrial origin and enriched in C-13, possibly due to lignin degradation.
CLIMATE OF THE PAST
(2022)