1
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Garcia AA, Chadwick GL, Liu XL, Welander PV. Identification of two archaeal GDGT lipid-modifying proteins reveals diverse microbes capable of GMGT biosynthesis and modification. Proc Natl Acad Sci U S A 2024; 121:e2318761121. [PMID: 38885389 PMCID: PMC11214058 DOI: 10.1073/pnas.2318761121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 05/15/2024] [Indexed: 06/20/2024] Open
Abstract
Archaea produce unique membrane-spanning lipids (MSLs), termed glycerol dialkyl glycerol tetraethers (GDGTs), which aid in adaptive responses to various environmental challenges. GDGTs can be modified through cyclization, cross-linking, methylation, hydroxylation, and desaturation, resulting in structurally distinct GDGT lipids. Here, we report the identification of radical SAM proteins responsible for two of these modifications-a glycerol monoalkyl glycerol tetraether (GMGT) synthase (Gms), responsible for covalently cross-linking the two hydrocarbon tails of a GDGT to produce GMGTs, and a GMGT methylase (Gmm), capable of methylating the core hydrocarbon tail. Heterologous expression of Gms proteins from various archaea in Thermococcus kodakarensis results in the production of GMGTs in two isomeric forms. Further, coexpression of Gms and Gmm produces mono- and dimethylated GMGTs and minor amounts of trimethylated GMGTs with only trace GDGT methylation. Phylogenetic analyses reveal the presence of Gms homologs in diverse archaeal genomes spanning all four archaeal superphyla and in multiple bacterial phyla with the genetic potential to synthesize fatty acid-based MSLs, demonstrating that GMGT production may be more widespread than previously appreciated. We demonstrate GMGT production in three Gms-encoding archaea, identifying an increase in GMGTs in response to elevated temperature in two Archaeoglobus species and the production of GMGTs with up to six rings in Vulcanisaeta distributa. The occurrence of such highly cyclized GMGTs has been limited to environmental samples and their detection in culture demonstrates the utility of combining genetic, bioinformatic, and lipid analyses to identify producers of distinct archaeal membrane lipids.
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Affiliation(s)
- Andy A. Garcia
- Department of Earth System Science, Stanford University, Stanford, CA94305
| | - Grayson L. Chadwick
- Department of Molecular and Cell Biology, University of California, Berkeley, CA94720
| | - Xiao-Lei Liu
- Department of Geology and Geophysics, University of Oklahoma, Norman, OK73019
| | - Paula V. Welander
- Department of Earth System Science, Stanford University, Stanford, CA94305
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2
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Liman GLS, Garcia AA, Fluke KA, Anderson HR, Davidson SC, Welander PV, Santangelo TJ. Tetraether archaeal lipids promote long-term survival in extreme conditions. Mol Microbiol 2024; 121:882-894. [PMID: 38372181 PMCID: PMC11096074 DOI: 10.1111/mmi.15240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 01/24/2024] [Accepted: 01/31/2024] [Indexed: 02/20/2024]
Abstract
The sole unifying feature of the incredibly diverse Archaea is their isoprenoid-based ether-linked lipid membranes. Unique lipid membrane composition, including an abundance of membrane-spanning tetraether lipids, impart resistance to extreme conditions. Many questions remain, however, regarding the synthesis and modification of tetraether lipids and how dynamic changes to archaeal lipid membrane composition support hyperthermophily. Tetraether membranes, termed glycerol dibiphytanyl glycerol tetraethers (GDGTs), are generated by tetraether synthase (Tes) by joining the tails of two bilayer lipids known as archaeol. GDGTs are often further specialized through the addition of cyclopentane rings by GDGT ring synthase (Grs). A positive correlation between relative GDGT abundance and entry into stationary phase growth has been observed, but the physiological impact of inhibiting GDGT synthesis has not previously been reported. Here, we demonstrate that the model hyperthermophile Thermococcus kodakarensis remains viable when Tes (TK2145) or Grs (TK0167) are deleted, permitting phenotypic and lipid analyses at different temperatures. The absence of cyclopentane rings in GDGTs does not impact growth in T. kodakarensis, but an overabundance of rings due to ectopic Grs expression is highly fitness negative at supra-optimal temperatures. In contrast, deletion of Tes resulted in the loss of all GDGTs, cyclization of archaeol, and loss of viability upon transition to the stationary phase in this model archaea. These results demonstrate the critical roles of highly specialized, dynamic, isoprenoid-based lipid membranes for archaeal survival at high temperatures.
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Affiliation(s)
- Geraldy Lie Stefanus Liman
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Andy A. Garcia
- Department of Earth System Science, Stanford University, Stanford, CA 94305, USA
| | - Kristin A. Fluke
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO 80523, USA
| | | | - Sarah C. Davidson
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - Paula V. Welander
- Department of Earth System Science, Stanford University, Stanford, CA 94305, USA
| | - Thomas J. Santangelo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
- Cell and Molecular Biology Graduate Program, Colorado State University, Fort Collins, CO 80523, USA
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3
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Hou S, Stap LB, Paul R, Nelissen M, Hoem FS, Ziegler M, Sluijs A, Sangiorgi F, Bijl PK. Reconciling Southern Ocean fronts equatorward migration with minor Antarctic ice volume change during Miocene cooling. Nat Commun 2023; 14:7230. [PMID: 37945579 PMCID: PMC10636158 DOI: 10.1038/s41467-023-43106-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/31/2023] [Indexed: 11/12/2023] Open
Abstract
Gradual climate cooling and CO2 decline in the Miocene were recently shown not to be associated with major ice volume expansion, challenging a fundamental paradigm in the functioning of the Antarctic cryosphere. Here, we explore Miocene ice-ocean-climate interactions by presenting a multi-proxy reconstruction of subtropical front migration, bottom water temperature and global ice volume change, using dinoflagellate cyst biogeography, benthic foraminiferal clumped isotopes from offshore Tasmania. We report an equatorward frontal migration and strengthening, concurrent with surface and deep ocean cooling but absence of ice volume change in the mid-late-Miocene. To reconcile these counterintuitive findings, we argue based on new ice sheet modelling that the Antarctic ice sheet progressively lowered in height while expanding seawards, to maintain a stable volume. This can be achieved with rigorous intervention in model precipitation regimes on Antarctica and ice-induced ocean cooling and requires rethinking the interactions between ice, ocean and climate.
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Affiliation(s)
- Suning Hou
- Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands.
| | - Lennert B Stap
- Institute for Marine and Atmospheric research Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Ryan Paul
- Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
| | - Mei Nelissen
- NIOZ Royal Netherlands Institute of Sea Research, Texel, The Netherlands
| | - Frida S Hoem
- Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
| | - Martin Ziegler
- Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
| | - Appy Sluijs
- Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
| | | | - Peter K Bijl
- Department of Earth Sciences, Utrecht University, Utrecht, The Netherlands
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4
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De Lira Mota MA, Dunkley Jones T, Sulaiman N, Edgar KM, Yamaguchi T, Leng MJ, Adloff M, Greene SE, Norris R, Warren B, Duffy G, Farrant J, Murayama M, Hall J, Bendle J. Multi-proxy evidence for sea level fall at the onset of the Eocene-Oligocene transition. Nat Commun 2023; 14:4748. [PMID: 37553323 PMCID: PMC10409788 DOI: 10.1038/s41467-023-39806-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 06/27/2023] [Indexed: 08/10/2023] Open
Abstract
Continental-scale expansion of the East Antarctic Ice Sheet during the Eocene-Oligocene Transition (EOT) is one of the largest non-linear events in Earth's climate history. Declining atmospheric carbon dioxide concentrations and orbital variability triggered glacial expansion and strong feedbacks in the climate system. Prominent among these feedbacks was the repartitioning of biogeochemical cycles between the continental shelves and the deep ocean with falling sea level. Here we present multiple proxies from a shallow shelf location that identify a marked regression and an elevated flux of continental-derived organic matter at the earliest stage of the EOT, a time of deep ocean carbonate dissolution and the extinction of oligotrophic phytoplankton groups. We link these observations using an Earth System model, whereby this first regression delivers a pulse of organic carbon to the oceans that could drive the observed patterns of deep ocean dissolution and acts as a transient negative feedback to climate cooling.
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Affiliation(s)
- Marcelo A De Lira Mota
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
- Institute of Geosciences, University of São Paulo, Rua do Lago, 562 - Butantã, São Paulo, SP, 05508-080, Brazil.
| | - Tom Dunkley Jones
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Nursufiah Sulaiman
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
- Faculty of Earth Science, Universiti Malaysia Kelantan Jeli Campus, Locked Bag No 100, 17600, Jeli, Kelantan, Malaysia
| | - Kirsty M Edgar
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Tatsuhiko Yamaguchi
- National Museum of Nature and Science, 4-1-1 Amakubo, Tsukuba, 305-0005, Japan
- Center for Advanced Marine Core Research, Kochi University, 200 Monobe Otsu, Nankoku, Kochi, 783-8502, Japan
| | - Melanie J Leng
- British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
- Centre for Environmental Geochemistry, School of Biosciences, University of Nottingham, Nottingham, LE12 5RD, UK
| | - Markus Adloff
- School of Geographical Sciences, University of Bristol, University Road, Bristol, BS81SS, UK
- Oeschger Centre, University of Bern, Hochschulstrasse 6, 3012, Bern, Switzerland
| | - Sarah E Greene
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Richard Norris
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093, USA
| | - Bridget Warren
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Grace Duffy
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Jennifer Farrant
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Masafumi Murayama
- Center for Advanced Marine Core Research, Kochi University, 200 Monobe Otsu, Nankoku, Kochi, 783-8502, Japan
- Faculty of Agriculture and Marine Science, Kochi University, B200 Monobe, Nankoku, Kochi, 783-8502, Japan
| | - Jonathan Hall
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - James Bendle
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK
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5
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Abstract
Archaeal membrane lipids are widely used for paleotemperature reconstructions, yet these molecular fossils also bear rich information about ecology and evolution of marine ammonia-oxidizing archaea (AOA). Here we identified thermal and nonthermal behaviors of archaeal glycerol dialkyl glycerol tetraethers (GDGTs) by comparing the GDGT-based temperature index (TEX86) to the ratio of GDGTs with two and three cyclopentane rings (GDGT-2/GDGT-3). Thermal-dependent biosynthesis should increase TEX86 and decrease GDGT-2/GDGT-3 when the ambient temperature increases. This presumed temperature-dependent (PTD) trend is observed in GDGTs derived from cultures of thermophilic and mesophilic AOA. The distribution of GDGTs in suspended particulate matter (SPM) and sediments collected from above the pycnocline-shallow water samples-also follows the PTD trend. These similar GDGT distributions between AOA cultures and shallow water environmental samples reflect shallow ecotypes of marine AOA. While there are currently no cultures of deep AOA clades, GDGTs derived from deep water SPM and marine sediment samples exhibit nonthermal behavior deviating from the PTD trend. The presence of deep AOA increases the GDGT-2/GDGT-3 ratio and distorts the temperature-controlled correlation between GDGT-2/GDGT-3 and TEX86. We then used Gaussian mixture models to statistically characterize these diagnostic patterns of modern AOA ecology from paleo-GDGT records to infer the evolution of marine AOA from the Mid-Mesozoic to the present. Long-term GDGT-2/GDGT-3 trends suggest a suppression of today's deep water marine AOA during the Mesozoic-early Cenozoic greenhouse climates. Our analysis provides invaluable insights into the evolutionary timeline and the expansion of AOA niches associated with major oceanographic and climate changes.
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6
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Summons RE, Welander PV, Gold DA. Lipid biomarkers: molecular tools for illuminating the history of microbial life. Nat Rev Microbiol 2022; 20:174-185. [PMID: 34635851 DOI: 10.1038/s41579-021-00636-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 11/09/2022]
Abstract
Fossilized lipids preserved in sedimentary rocks offer singular insights into the Earth's palaeobiology. These 'biomarkers' encode information pertaining to the oxygenation of the atmosphere and oceans, transitions in ocean plankton, the greening of continents, mass extinctions and climate change. Historically, biomarker interpretations relied on inventories of lipids present in extant microorganisms and counterparts in natural environments. However, progress has been impeded because only a small fraction of the Earth's microorganisms can be cultured, many environmentally significant microorganisms from the past no longer exist and there are gaping holes in knowledge concerning lipid biosynthesis. The revolution in genomics and bioinformatics has provided new tools to expand our understanding of lipid biomarkers, their biosynthetic pathways and distributions in nature. In this Review, we explore how preserved organic molecules provide a unique perspective on the history of the Earth's microbial life. We discuss how advances in molecular biology have helped elucidate biomarker origins and afforded more robust interpretations of fossil lipids and how the rock record provides vital calibration points for molecular clocks. Such studies are open to further exploitation with the expansion of sequenced microbial genomes in accessible databases.
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Affiliation(s)
- Roger E Summons
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Paula V Welander
- Department of Earth System Science, Stanford University, Stanford, CA, USA
| | - David A Gold
- Department of Earth & Planetary Sciences, University of California Davis, Davis, CA, USA
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7
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Impact of global cooling on Early Cretaceous high pCO 2 world during the Weissert Event. Nat Commun 2021; 12:5411. [PMID: 34518550 PMCID: PMC8437947 DOI: 10.1038/s41467-021-25706-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 08/12/2021] [Indexed: 02/08/2023] Open
Abstract
The Weissert Event ~133 million years ago marked a profound global cooling that punctuated the Early Cretaceous greenhouse. We present modelling, high-resolution bulk organic carbon isotopes and chronostratigraphically calibrated sea surface temperature (SSTs) based on an organic paleothermometer (the TEX86 proxy), which capture the Weissert Event in the semi-enclosed Weddell Sea basin, offshore Antarctica (paleolatitude ~54 °S; paleowater depth ~500 meters). We document a ~3-4 °C drop in SST coinciding with the Weissert cold end, and converge the Weddell Sea data, climate simulations and available worldwide multi-proxy based temperature data towards one unifying solution providing a best-fit between all lines of evidence. The outcome confirms a 3.0 °C ( ±1.7 °C) global mean surface cooling across the Weissert Event, which translates into a ~40% drop in atmospheric pCO2 over a period of ~700 thousand years. Consistent with geologic evidence, this pCO2 drop favoured the potential build-up of local polar ice.
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8
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Song H, Kemp DB, Tian L, Chu D, Song H, Dai X. Thresholds of temperature change for mass extinctions. Nat Commun 2021; 12:4694. [PMID: 34349121 PMCID: PMC8338942 DOI: 10.1038/s41467-021-25019-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 07/16/2021] [Indexed: 11/26/2022] Open
Abstract
Climate change is a critical factor affecting biodiversity. However, the quantitative relationship between temperature change and extinction is unclear. Here, we analyze magnitudes and rates of temperature change and extinction rates of marine fossils through the past 450 million years (Myr). The results show that both the rate and magnitude of temperature change are significantly positively correlated with the extinction rate of marine animals. Major mass extinctions in the Phanerozoic can be linked to thresholds in climate change (warming or cooling) that equate to magnitudes >5.2 °C and rates >10 °C/Myr. The significant relationship between temperature change and extinction still exists when we exclude the five largest mass extinctions of the Phanerozoic. Our findings predict that a temperature increase of 5.2 °C above the pre-industrial level at present rates of increase would likely result in mass extinction comparable to that of the major Phanerozoic events, even without other, non-climatic anthropogenic impacts.
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Affiliation(s)
- Haijun Song
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China.
| | - David B Kemp
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Li Tian
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Daoliang Chu
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Huyue Song
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
| | - Xu Dai
- State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, China University of Geosciences, Wuhan, China
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9
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More KD, Wuchter C, Irigoien X, Tierney JE, Giosan L, Grice K, Coolen MJL. Subseafloor Archaea reflect 139 kyrs of paleodepositional changes in the northern Red Sea. GEOBIOLOGY 2021; 19:162-172. [PMID: 33274598 DOI: 10.1111/gbi.12421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 09/18/2020] [Accepted: 10/26/2020] [Indexed: 06/12/2023]
Abstract
The vertical distribution of subseafloor archaeal communities is thought to be primarily controlled by in situ conditions in sediments such as the availability of electron acceptors and donors, although sharp community shifts have also been observed at lithological boundaries suggesting that at least a subset of vertically stratified Archaea form a long-term genetic record of coinciding environmental conditions that occurred at the time of sediment deposition. To substantiate this possibility, we performed a highly resolved 16S rRNA gene survey of vertically stratified archaeal communities paired with paleo-oceanographic proxies in a sedimentary record from the northern Red Sea spanning the last glacial-interglacial cycle (i.e., marine isotope stages 1-6; MIS1-6). Our results show a strong significant correlation between subseafloor archaeal communities and drastic paleodepositional changes associated with glacial low vs. interglacial high stands (ANOSIM; R = .73; p = .001) and only a moderately strong correlation with lithological changes. Bathyarchaeota, Lokiarchaeota, MBGA, and DHVEG-1 were the most abundant identified archaeal groups. Whether they represented ancient cell lines from the time of deposition or migrated to the specific sedimentary horizons after deposition remains speculative. However, we show that the majority of sedimentary archaeal tetraether membrane lipids were of allochthonous origin and not produced in situ. Slow post-burial growth under energy-limited conditions would explain why the downcore distribution of these dominant archaeal groups still indirectly reflect changes in the paleodepositional environment that prevailed during the analyzed marine isotope stages. In addition, archaea seeded from the overlying water column such as Thaumarchaeota and group II and III Euryarchaeota, which were likely not have been able to subsist after burial, were identified from a lower abundance of preserved sedimentary DNA signatures, and represented direct markers of paleoenvironmental changes in the Red Sea spanning the last six marine isotope stages.
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Affiliation(s)
- Kuldeep D More
- Western Australia Organic and Isotope Geochemistry Centre, School of Molecular and Life Sciences, Curtin University, Bentley, Western Australia, Australia
| | - Cornelia Wuchter
- Western Australia Organic and Isotope Geochemistry Centre, School of Earth and Planetary Sciences, The Institute for Geoscience Research (TIGeR), Curtin University, Bentley, Western Australia, Australia
| | - Xabier Irigoien
- AZTI-Tecnalia, Pasaia Gipuzkoa, Spain
- IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Jessica E Tierney
- Department of Geosciences, University of Arizona, Tucson, Arizona, USA
| | - Liviu Giosan
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Falmouth, Massachusetts, USA
| | - Kliti Grice
- Western Australia Organic and Isotope Geochemistry Centre, School of Earth and Planetary Sciences, The Institute for Geoscience Research (TIGeR), Curtin University, Bentley, Western Australia, Australia
| | - Marco J L Coolen
- Western Australia Organic and Isotope Geochemistry Centre, School of Earth and Planetary Sciences, The Institute for Geoscience Research (TIGeR), Curtin University, Bentley, Western Australia, Australia
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10
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Cramwinckel MJ, Coxall HK, Śliwińska KK, Polling M, Harper DT, Bijl PK, Brinkhuis H, Eldrett JS, Houben AJP, Peterse F, Schouten S, Reichart G, Zachos JC, Sluijs A. A Warm, Stratified, and Restricted Labrador Sea Across the Middle Eocene and Its Climatic Optimum. PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 2020; 35:e2020PA003932. [PMID: 33134852 PMCID: PMC7590098 DOI: 10.1029/2020pa003932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 07/14/2020] [Accepted: 07/29/2020] [Indexed: 06/11/2023]
Abstract
Several studies indicate that North Atlantic Deep Water (NADW) formation might have initiated during the globally warm Eocene (56-34 Ma). However, constraints on Eocene surface ocean conditions in source regions presently conducive to deep water formation are sparse. Here we test whether ocean conditions of the middle Eocene Labrador Sea might have allowed for deep water formation by applying (organic) geochemical and palynological techniques, on sediments from Ocean Drilling Program (ODP) Site 647. We reconstruct a long-term sea surface temperature (SST) drop from ~30°C to ~27°C between 41.5 to 38.5 Ma, based on TEX86. Superimposed on this trend, we record ~2°C warming in SST associated with the Middle Eocene Climatic Optimum (MECO; ~40 Ma), which is the northernmost MECO record as yet, and another, likely regional, warming phase at ~41.1 Ma, associated with low-latitude planktic foraminifera and dinoflagellate cyst incursions. Dinoflagellate cyst assemblages together with planktonic foraminiferal stable oxygen isotope ratios overall indicate low surface water salinities and strong stratification. Benthic foraminifer stable carbon and oxygen isotope ratios differ from global deep ocean values by 1-2‰ and 2-4‰, respectively, indicating geographic basin isolation. Our multiproxy reconstructions depict a consistent picture of relatively warm and fresh but also highly variable surface ocean conditions in the middle Eocene Labrador Sea. These conditions were unlikely conducive to deep water formation. This implies either NADW did not yet form during the middle Eocene or it formed in a different source region and subsequently bypassed the southern Labrador Sea.
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Affiliation(s)
- Margot J. Cramwinckel
- Department of Earth Sciences, Faculty of GeoscienceUtrecht UniversityUtrechtThe Netherlands
- Now at School of Ocean and Earth Science, National Oceanography Centre SouthamptonUniversity of SouthamptonSouthamptonUK
| | - Helen K. Coxall
- Department of Geological SciencesStockholm UniversityStockholmSweden
| | | | - Marcel Polling
- Department of Earth Sciences, Faculty of GeoscienceUtrecht UniversityUtrechtThe Netherlands
- Now at Naturalis Biodiversity CenterLeidenThe Netherlands
| | - Dustin T. Harper
- Department of Earth and Planetary SciencesUniversity of CaliforniaSanta CruzCAUSA
- Now at Department of GeologyThe University of KansasLawrenceKSUSA
| | - Peter K. Bijl
- Department of Earth Sciences, Faculty of GeoscienceUtrecht UniversityUtrechtThe Netherlands
| | - Henk Brinkhuis
- Department of Earth Sciences, Faculty of GeoscienceUtrecht UniversityUtrechtThe Netherlands
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht UniversityDen BurgThe Netherlands
| | - James S. Eldrett
- Shell International Exploration and Production B. V.RijswijkThe Netherlands
| | - Alexander J. P. Houben
- Applied Geosciences TeamNetherlands Organisation for Applied Scientific Research (TNO)UtrechtThe Netherlands
| | - Francien Peterse
- Department of Earth Sciences, Faculty of GeoscienceUtrecht UniversityUtrechtThe Netherlands
| | - Stefan Schouten
- Department of Earth Sciences, Faculty of GeoscienceUtrecht UniversityUtrechtThe Netherlands
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht UniversityDen BurgThe Netherlands
| | - Gert‐Jan Reichart
- Department of Earth Sciences, Faculty of GeoscienceUtrecht UniversityUtrechtThe Netherlands
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, and Utrecht UniversityDen BurgThe Netherlands
| | | | - Appy Sluijs
- Department of Earth Sciences, Faculty of GeoscienceUtrecht UniversityUtrechtThe Netherlands
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11
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Abstract
During the Eocene, high-latitude regions were much warmer than today and substantial polar ice sheets were lacking. Indeed, the initiation of significant polar ice sheets near the end of the Eocene has been closely linked to global cooling. Here, we examine the relationship between global temperatures and continental-scale polar ice sheets following the establishment of ice sheets on Antarctica ∼34 million years ago, using records of surface temperatures from around the world. We find that high-latitude temperatures were almost as warm after the initiation of Antarctic glaciation as before, challenging our basic understanding of how climate works, and of the development of climate and ice volume through time. Falling atmospheric CO2 levels led to cooling through the Eocene and the expansion of Antarctic ice sheets close to their modern size near the beginning of the Oligocene, a period of poorly documented climate. Here, we present a record of climate evolution across the entire Oligocene (33.9 to 23.0 Ma) based on TEX86 sea surface temperature (SST) estimates from southwestern Atlantic Deep Sea Drilling Project Site 516 (paleolatitude ∼36°S) and western equatorial Atlantic Ocean Drilling Project Site 929 (paleolatitude ∼0°), combined with a compilation of existing SST records and climate modeling. In this relatively low CO2 Oligocene world (∼300 to 700 ppm), warm climates similar to those of the late Eocene continued with only brief interruptions, while the Antarctic ice sheet waxed and waned. SSTs are spatially heterogenous, but generally support late Oligocene warming coincident with declining atmospheric CO2. This Oligocene warmth, especially at high latitudes, belies a simple relationship between climate and atmospheric CO2 and/or ocean gateways, and is only partially explained by current climate models. Although the dominant climate drivers of this enigmatic Oligocene world remain unclear, our results help fill a gap in understanding past Cenozoic climates and the way long-term climate sensitivity responded to varying background climate states.
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12
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Vickers ML, Lengger SK, Bernasconi SM, Thibault N, Schultz BP, Fernandez A, Ullmann CV, McCormack P, Bjerrum CJ, Rasmussen JA, Hougård IW, Korte C. Cold spells in the Nordic Seas during the early Eocene Greenhouse. Nat Commun 2020; 11:4713. [PMID: 32948769 PMCID: PMC7501286 DOI: 10.1038/s41467-020-18558-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 08/21/2020] [Indexed: 11/18/2022] Open
Abstract
The early Eocene (c. 56 - 48 million years ago) experienced some of the highest global temperatures in Earth’s history since the Mesozoic, with no polar ice. Reports of contradictory ice-rafted erratics and cold water glendonites in the higher latitudes have been largely dismissed due to ambiguity of the significance of these purported cold-climate indicators. Here we apply clumped isotope paleothermometry to a traditionally qualitative abiotic proxy, glendonite calcite, to generate quantitative temperature estimates for northern mid-latitude bottom waters. Our data show that the glendonites of the Danish Basin formed in waters below 5 °C, at water depths of <300 m. Such near-freezing temperatures have not previously been reconstructed from proxy data for anywhere on the early Eocene Earth, and these data therefore suggest that regionalised cool episodes punctuated the background warmth of the early Eocene, likely linked to eruptive phases of the North Atlantic Igneous Province. The early Eocene was characterized by exceptionally high global temperatures and no polar ice. Here, clumped isotope paleothermometry of glendonite calcite from the Danish Basin shows that these were formed in waters below 5 °C, indicating that regionalised cool episodes punctuated the background warmth of the early Eocene.
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Affiliation(s)
- Madeleine L Vickers
- IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark.
| | - Sabine K Lengger
- Biogeochemistry Research Centre, School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK
| | | | - Nicolas Thibault
- IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
| | | | - Alvaro Fernandez
- Bjerknes Centre for Climate Research and Department of Earth Science, University of Bergen, Allégaten 41, N-5007, Bergen, Norway
| | - Clemens V Ullmann
- Camborne School of Mines, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE, UK
| | - Paul McCormack
- Biogeochemistry Research Centre, School of Geography, Earth and Environmental Sciences, Plymouth University, Drake Circus, Plymouth, PL4 8AA, UK
| | - Christian J Bjerrum
- IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
| | - Jan Audun Rasmussen
- Museum Mors, Fossil- and Mo-clay Museum, Skarrehagevej 8, 7900, Nykøbing Mors, Denmark
| | | | - Christoph Korte
- IGN, University of Copenhagen, Øster Voldgade 10, DK-1350, Copenhagen, Denmark
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13
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Ma C, Coffinet S, Lipp JS, Hinrichs KU, Zhang C. Marine Group II Euryarchaeota Contribute to the Archaeal Lipid Pool in Northwestern Pacific Ocean Surface Waters. Front Microbiol 2020; 11:1034. [PMID: 32582055 PMCID: PMC7291766 DOI: 10.3389/fmicb.2020.01034] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 04/27/2020] [Indexed: 12/17/2022] Open
Abstract
Planktonic archaea include predominantly Marine Group I Thaumarchaeota (MG I) and Marine Group II Euryarchaeota (MG II), which play important roles in the oceanic carbon cycle. MG I produce specific lipids called isoprenoid glycerol dibiphytanyl glycerol tetraethers (GDGTs), which are being used in the sea surface temperature proxy named TEX86. Although MG II may be the most abundant planktonic archaeal group in surface water, their lipid composition remains poorly characterized because of the lack of cultured representatives. Circumstantial evidence from previous studies of marine suspended particulate matter suggests that MG II may produce both GDGTs and archaeol-based lipids. In this study, integration of the 16S rRNA gene quantification and sequencing and lipid analysis demonstrated that MG II contributed significantly to the pool of archaeal tetraether lipids in samples collected from MG II-dominated surface waters of the Northwestern Pacific Ocean (NWPO). The archaeal lipid composition in MG II-dominated NWPO waters differed significantly from that of known MG I cultures, containing relatively more 2G-OH-, 2G- and 1G- GDGTs, especially in their acyclic form. Lipid composition in NWPO waters was also markedly different from MG I-dominated surface water samples collected in the East China Sea. GDGTs from MG II-dominated samples seemed to respond to temperature similarly to GDGTs from the MG I-dominated samples, which calls for further study using pure cultures to determine the exact impact of MG II on GDGT-based proxies.
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Affiliation(s)
- Cenling Ma
- State Key Laboratory of Marine Geology, Tongji University, Shanghai, China
| | - Sarah Coffinet
- Organic Geochemistry Group, MARUM Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Julius S Lipp
- Organic Geochemistry Group, MARUM Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Kai-Uwe Hinrichs
- Organic Geochemistry Group, MARUM Center for Marine Environmental Sciences and Department of Geosciences, University of Bremen, Bremen, Germany
| | - Chuanlun Zhang
- Shenzhen Key Laboratory of Marine Archaea Geo-Omics, Southern University of Science and Technology, Shenzhen, China.,Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
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14
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Śliwińska KK, Thomsen E, Schouten S, Schoon PL, Heilmann-Clausen C. Climate- and gateway-driven cooling of Late Eocene to earliest Oligocene sea surface temperatures in the North Sea Basin. Sci Rep 2019; 9:4458. [PMID: 30872690 PMCID: PMC6418185 DOI: 10.1038/s41598-019-41013-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 02/27/2019] [Indexed: 11/09/2022] Open
Abstract
During the late Eocene, the Earth’s climate experienced several transient temperature fluctuations including the Vonhof cooling event (C16n.1n; ~35.8 Ma) hitherto known mainly from the southern oceans. Here we reconstruct sea-surface temperatures (SST) and provide δ18O and δ13C foraminiferal records for the late Eocene and earliest Oligocene in the North Sea Basin. Our data reveal two main perturbations: (1), an abrupt brief cooling of ~4.5 °C dated to ~35.8 Ma and synchronous with the Vonhof cooling, which thus may be a global event, and (2) a gradual nearly 10 °C temperature fall starting at 36.1 Ma and culminating near the Eocene-Oligocene transition at ~33.9 Ma. The late Priabonian temperature trend in the North Sea shows some resemblance IODP Site U1404 from the North Atlantic, offshore Newfoundland; and is in contrast to the more abrupt change observed in the deep-sea δ18O records from the southern oceans. The cooling in the North Sea is large compared to the pattern seen in the North Atlantic record. This difference may be influenced by a late Eocene closure of the warm gateways connecting the North Sea with the Atlantic and Tethys oceans.
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Affiliation(s)
- Kasia K Śliwińska
- GEUS Geological Survey of Denmark and Greenland, Department of Stratigraphy, Øster Voldgade 10, 1350, Copenhagen K, Denmark.
| | - Erik Thomsen
- Aarhus University, Department of Geoscience, Høegh-Guldbergs Gade 2, 8000, Århus C, Denmark
| | - Stefan Schouten
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, Texel, The Netherlands.,Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Petra L Schoon
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry, Utrecht University, Texel, The Netherlands
| | - Claus Heilmann-Clausen
- Aarhus University, Department of Geoscience, Høegh-Guldbergs Gade 2, 8000, Århus C, Denmark
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15
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DiNezio PN, Tierney JE, Otto-Bliesner BL, Timmermann A, Bhattacharya T, Rosenbloom N, Brady E. Glacial changes in tropical climate amplified by the Indian Ocean. SCIENCE ADVANCES 2018; 4:eaat9658. [PMID: 30547084 PMCID: PMC6291310 DOI: 10.1126/sciadv.aat9658] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 11/14/2018] [Indexed: 05/26/2023]
Abstract
The mechanisms driving glacial-interglacial changes in the climate of the Indo-Pacific warm pool are poorly understood. Here, we address this question by combining paleoclimate proxies with model simulations of the Last Glacial Maximum climate. We find evidence of two mechanisms explaining key patterns of ocean cooling and rainfall change interpreted from proxy data. Exposure of the Sahul shelf excites a positive ocean-atmosphere feedback involving a stronger surface temperature gradient along the equatorial Indian Ocean and a weaker Walker circulation-a response explaining the drier/wetter dipole across the basin. Northern Hemisphere cooling by ice sheet albedo drives a monsoonal retreat across Africa and the Arabian Peninsula-a response that triggers a weakening of the Indian monsoon via cooling of the Arabian Sea and associated reductions in moisture supply. These results demonstrate the importance of air-sea interactions in the Indian Ocean, amplifying externally forced climate changes over a large part of the tropics.
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Affiliation(s)
- Pedro N. DiNezio
- Institute for Geophysics, Jackson School of Geosciences, University of Texas at Austin, J.J. Pickle Research Campus, Building 196 10100 Burnet Road (R2200), Austin, TX 78758, USA
| | - Jessica E. Tierney
- Department of Geosciences, The University of Arizona, 1040 E 4th Street, Tucson, AZ 85721, USA
| | - Bette L. Otto-Bliesner
- National Center for Atmospheric Research, Climate and Global Dynamics Laboratory, 1850 Table Mesa Drive, Boulder, CO 80305, USA
| | - Axel Timmermann
- Center for Climate Physics, Institute for Basic Science, Busandaehak-ro 63beon-gil 2, Geumjeong-gu, Busan 46241, South Korea
- Pusan National University, Busandaehak-ro 63beon-gil 2, Geumjeong-gu, Busan 46241, South Korea
| | - Tripti Bhattacharya
- Department of Earth Science, Syracuse University, 204 Heroy Geology Laboratory, Syracuse, NY 13244-1070, USA
| | - Nan Rosenbloom
- National Center for Atmospheric Research, Climate and Global Dynamics Laboratory, 1850 Table Mesa Drive, Boulder, CO 80305, USA
| | - Esther Brady
- National Center for Atmospheric Research, Climate and Global Dynamics Laboratory, 1850 Table Mesa Drive, Boulder, CO 80305, USA
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16
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Cramwinckel MJ, Huber M, Kocken IJ, Agnini C, Bijl PK, Bohaty SM, Frieling J, Goldner A, Hilgen FJ, Kip EL, Peterse F, van der Ploeg R, Röhl U, Schouten S, Sluijs A. Synchronous tropical and polar temperature evolution in the Eocene. Nature 2018; 559:382-386. [PMID: 29967546 DOI: 10.1038/s41586-018-0272-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 04/13/2018] [Indexed: 11/09/2022]
Abstract
Palaeoclimate reconstructions of periods with warm climates and high atmospheric CO2 concentrations are crucial for developing better projections of future climate change. Deep-ocean1,2 and high-latitude3 palaeotemperature proxies demonstrate that the Eocene epoch (56 to 34 million years ago) encompasses the warmest interval of the past 66 million years, followed by cooling towards the eventual establishment of ice caps on Antarctica. Eocene polar warmth is well established, so the main obstacle in quantifying the evolution of key climate parameters, such as global average temperature change and its polar amplification, is the lack of continuous high-quality tropical temperature reconstructions. Here we present a continuous Eocene equatorial sea surface temperature record, based on biomarker palaeothermometry applied on Atlantic Ocean sediments. We combine this record with the sparse existing data4-6 to construct a 26-million-year multi-proxy, multi-site stack of Eocene tropical climate evolution. We find that tropical and deep-ocean temperatures changed in parallel, under the influence of both long-term climate trends and short-lived events. This is consistent with the hypothesis that greenhouse gas forcing7,8, rather than changes in ocean circulation9,10, was the main driver of Eocene climate. Moreover, we observe a strong linear relationship between tropical and deep-ocean temperatures, which implies a constant polar amplification factor throughout the generally ice-free Eocene. Quantitative comparison with fully coupled climate model simulations indicates that global average temperatures were about 29, 26, 23 and 19 degrees Celsius in the early, early middle, late middle and late Eocene, respectively, compared to the preindustrial temperature of 14.4 degrees Celsius. Finally, combining proxy- and model-based temperature estimates with available CO2 reconstructions8 yields estimates of an Eocene Earth system sensitivity of 0.9 to 2.3 kelvin per watt per square metre at 68 per cent probability, consistent with the high end of previous estimates11.
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Affiliation(s)
- Margot J Cramwinckel
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands.
| | - Matthew Huber
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
| | - Ilja J Kocken
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Claudia Agnini
- Department of Geosciences, University of Padova, Padova, Italy
| | - Peter K Bijl
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Steven M Bohaty
- Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton, UK
| | - Joost Frieling
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Aaron Goldner
- Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN, USA
| | - Frederik J Hilgen
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Elizabeth L Kip
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Francien Peterse
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Robin van der Ploeg
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
| | - Ursula Röhl
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany
| | - Stefan Schouten
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands.,NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and Biogeochemistry and Utrecht University, Den Burg, The Netherlands
| | - Appy Sluijs
- Department of Earth Sciences, Faculty of Geoscience, Utrecht University, Utrecht, The Netherlands
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17
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Lattaud J, Lo L, Huang J, Chou Y, Gorbarenko SA, Sinninghe Damsté JS, Schouten S. A Comparison of Late Quaternary Organic Proxy-Based Paleotemperature Records of the Central Sea of Okhotsk. PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 2018; 33:732-744. [PMID: 32280935 PMCID: PMC7144895 DOI: 10.1029/2018pa003388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/12/2018] [Accepted: 06/15/2018] [Indexed: 06/11/2023]
Abstract
The long-chain diol index (LDI) is a new organic sea surface temperature (SST) proxy based on the distribution of long-chain diols. It has been applied in several environments but not yet in subpolar regions. Here we tested the LDI on surface sediments and a sediment core from the Sea of Okhotsk, which is the southernmost seasonal sea ice-covered region in the Northern Hemisphere, and compared it with other organic temperature proxies, that is, U 37 k ' and TEXL 86. In the surface sediments, the LDI is correlated with autumn SST, similar to the U 37 k ' but different from the TEXL 86 that correlates best with summer sea subsurface temperature. Remarkably, the obtained local LDI calibration was significantly different from the global core-top calibration. We used the local LDI calibration to reconstruct past SST changes in the central Sea of Okhotsk. The LDI-SST record shows low glacial (Marine Isotope Stage, MIS 2, 4, and 6) and high interglacial (MIS 1 and MIS 5) temperatures and follows the same pattern as the U 37 k ' -SST and a previously published TEXL 86 temperature record. Similar to the modern situation, the reconstructed temperatures during the interglacials likely reflect different seasons, that is, summer for the TEXL 86 and autumn for U 37 k ' and LDI. During glacials, the reconstructed temperatures of all three proxies are similar to each other, likely reflecting summer temperatures as this was the only season free of sea ice. Our results suggest that the LDI is a suitable proxy to reconstruct subpolar seawater temperatures.
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Affiliation(s)
- Julie Lattaud
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and BiogeochemistryUtrecht UniversityUtrechtNetherlands
| | - Li Lo
- State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhouChina
- Department of Earth SciencesUniversity of CambridgeCambridgeUK
| | - Jyh‐Jaan Huang
- Department of GeosciencesNational Taiwan UniversityTaipei CityTaiwan
- Now at Institute of GeologyUniversity of InnsbruckInnsbruckAustria
| | - Yu‐Min Chou
- Department of Ocean Sciences and EngineeringSouthern University of Science and TechnologyShenzheChina
| | - Sergey A. Gorbarenko
- V.I. Il'ichev Pacific Oceanological InstituteFar East Branch Russian Academy of ScienceVladivostokRussia
| | - Jaap S. Sinninghe Damsté
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and BiogeochemistryUtrecht UniversityUtrechtNetherlands
- Department of Earth Sciences, Faculty of Geosciences, Department of Earth SciencesUtrecht UniversityUtrechtNetherlands
| | - Stefan Schouten
- NIOZ Royal Netherlands Institute for Sea Research, Department of Marine Microbiology and BiogeochemistryUtrecht UniversityUtrechtNetherlands
- Department of Earth Sciences, Faculty of Geosciences, Department of Earth SciencesUtrecht UniversityUtrechtNetherlands
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18
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Influence of ammonia oxidation rate on thaumarchaeal lipid composition and the TEX86 temperature proxy. Proc Natl Acad Sci U S A 2016; 113:7762-7. [PMID: 27357675 DOI: 10.1073/pnas.1518534113] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Archaeal membrane lipids known as glycerol dibiphytanyl glycerol tetraethers (GDGTs) are the basis of the TEX86 paleotemperature proxy. Because GDGTs preserved in marine sediments are thought to originate mainly from planktonic, ammonia-oxidizing Thaumarchaeota, the basis of the correlation between TEX86 and sea surface temperature (SST) remains unresolved: How does TEX86 predict surface temperatures, when maximum thaumarchaeal activity occurs below the surface mixed layer and TEX86 does not covary with in situ growth temperatures? Here we used isothermal studies of the model thaumarchaeon Nitrosopumilus maritimus SCM1 to investigate how GDGT composition changes in response to ammonia oxidation rate. We used continuous culture methods to avoid potential confounding variables that can be associated with experiments in batch cultures. The results show that the ring index scales inversely (R(2) = 0.82) with ammonia oxidation rate (ϕ), indicating that GDGT cyclization depends on available reducing power. Correspondingly, the TEX86 ratio decreases by an equivalent of 5.4 °C of calculated temperature over a 5.5 fmol·cell(-1)·d(-1) increase in ϕ. This finding reconciles other recent experiments that have identified growth stage and oxygen availability as variables affecting TEX86 Depth profiles from the marine water column show minimum TEX86 values at the depth of maximum nitrification rates, consistent with our chemostat results. Our findings suggest that the TEX86 signal exported from the water column is influenced by the dynamics of ammonia oxidation. Thus, the global TEX86-SST calibration potentially represents a composite of regional correlations based on nutrient dynamics and global correlations based on archaeal community composition and temperature.
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