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Velay-Vitow J, Chandan D, Peltier WR. Into the Holocene, anatomy of the Younger Dryas cold reversal and preboreal oscillation. Sci Rep 2024; 14:3134. [PMID: 38326537 DOI: 10.1038/s41598-024-53591-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 02/01/2024] [Indexed: 02/09/2024] Open
Abstract
During the most recent deglaciation, the upwards trend of warmer Northern Hemisphere (NH) temperatures was punctuated by a rapid and intense return to glacial conditions: the Younger Dryas (YD). The end of this event marks the beginning of the Holocene. Using the University of Toronto version of CCSM4, a model of the climate prior to the YD was created with correct boundary conditions. Various amounts of freshwater forcing were then applied to the Beaufort Gyre for forcing intervals ranging from 1 to 125 years. In several cases, this was sufficient to collapse the Atlantic Meridional Overturning Circulation (AMOC) and cause significant cooling over the NH. Crucially, after the forcing was ceased, the AMOC stayed in an off state for approximately a millennium before mounting a rapid recover to pre-YD levels. This recovery, which permanently reduced the extent of NH sea ice, occurred through the mechanism of a Polynya opening in the Irminger Sea during winter and led to a pronounced "overshoot" of the AMOC, during which NH temperatures were higher than before the YD.
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Affiliation(s)
| | - Deepak Chandan
- Department of Physics, University of Toronto, Toronto, ON, Canada
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Martin KC, Buizert C, Edwards JS, Kalk ML, Riddell-Young B, Brook EJ, Beaudette R, Severinghaus JP, Sowers TA. Bipolar impact and phasing of Heinrich-type climate variability. Nature 2023; 617:100-104. [PMID: 37095266 DOI: 10.1038/s41586-023-05875-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 02/09/2023] [Indexed: 04/26/2023]
Abstract
During the last ice age, the Laurentide Ice Sheet exhibited extreme iceberg discharge events that are recorded in North Atlantic sediments1. These Heinrich events have far-reaching climate impacts, including widespread disruptions to hydrological and biogeochemical cycles2-4. They occurred during Heinrich stadials-cold periods with strongly weakened Atlantic overturning circulation5-7. Heinrich-type variability is not distinctive in Greenland water isotope ratios, a well-dated site temperature proxy8, complicating efforts to assess their regional climate impact and phasing against Antarctic climate change. Here we show that Heinrich events have no detectable temperature impact on Greenland and cooling occurs at the onset of several Heinrich stadials, and that both types of Heinrich variability have a distinct imprint on Antarctic climate. Antarctic ice cores show accelerated warming that is synchronous with increases in methane during Heinrich events, suggesting an atmospheric teleconnection9, despite the absence of a Greenland climate signal. Greenland ice-core nitrogen stable isotope ratios, a sensitive temperature proxy, indicate an abrupt cooling of about three degrees Celsius at the onset of Heinrich Stadial 1 (17.8 thousand years before present, where present is defined as 1950). Antarctic warming lags this cooling by 133 ± 93 years, consistent with an oceanic teleconnection. Paradoxically, proximal sites are less affected by Heinrich events than remote sites, suggesting spatially complex event dynamics.
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Affiliation(s)
- Kaden C Martin
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA.
| | - Christo Buizert
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Jon S Edwards
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Michael L Kalk
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Ben Riddell-Young
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Edward J Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Ross Beaudette
- Scripps Institution of Oceanography, University of California, San Diego, CA, USA
| | | | - Todd A Sowers
- Department of Geosciences, Pennsylvania State University, State College, PA, USA
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3
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Rapid warming linked to leap in tropical ocean seasonality. Nature 2022; 612:36-38. [DOI: 10.1038/d41586-022-03833-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
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4
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Pardi MI, DeSantis LRG. Interpreting spatially explicit variation in dietary proxies through species distribution modeling reveals foraging preferences of mammoth (Mammuthus) and American mastodon (Mammut americanum). Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1064299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
IntroductionThe end Pleistocene was a time of considerable ecological upheaval. Recent work has explored the megafauna extinction’s role in altering ecosystem processes. Analyses of functional traits withing communities reveal hidden consequences of the megafauna extinction beyond declines in taxonomic diversity. Functional diversity analyses offer new insight into our understanding of past ecosystems and may even inform future rewilding efforts. However, the utility of functional diversity may be hampered by the use of discrete, taxon-level functional traits, such as dietary categories, that mask variation in functional diversity over space and time.MethodsWe present an approach in which species distribution modeling, in Maxent, provides context for interpreting variation in two widely used proxies for diet among fossil taxa: stable isotope analysis and dental microwear texture analysis. We apply this approach to two ecologically distinct taxa, the American mastodon (Mammut americanum) and mammoths (Mammuthus) and investigate their resource use over space and time from the last glacial maximum to the end Pleistocene (25–11.7 thousand years before present).ResultsMammoth dietary behavior varies by context across their geographic distribution, despite possessing evolutionary adaptations that facilitate grazing. Mammoths exhibit a preference for grazing where species distribution modeling predicts the highest likelihood of occurrence but engage in more mixed-feeding outside of core likelihood areas. In contrast, dietary preferences for mastodon are less resolved and our analyses were unable to identify significant differences in diet across their distribution.DiscussionThe ecological roles of some species are context specific and need to be critically evaluated when planning for management of reintroductions or introducing novel species to restore lost ecological function.
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A Tibetan ice core covering the past 1,300 years radiometrically dated with 39Ar. Proc Natl Acad Sci U S A 2022; 119:e2200835119. [PMID: 36161936 DOI: 10.1073/pnas.2200835119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ice cores from alpine glaciers are unique archives of past global and regional climate conditions. However, recovering climate records from these ice cores is often hindered by the lack of a reliable chronology, especially in the age range of 100 to 500 anni (a) for which radiometric dating has not been available so far. We report on radiometric 39Ar dating of an ice core from the Tibetan Plateau and the construction of a chronology covering the past 1,300 a using the obtained 39Ar ages. This is made possible by advances in the analysis of 39Ar using the laser-based detection method atom trap trace analysis, resulting in a twofold increase in the upper age limit of 39Ar dating. By measuring the anthropogenic 85Kr along with 39Ar we quantify and correct modern air contamination, thus removing a major systematic uncertainty of 39Ar dating. Moreover, the 85Kr data for the top part of the ice core provide information on firn processes, including the age difference between the ice and its enclosed gas. This first application of 39Ar and 85Kr to an ice core facilitates further ice cores from nonpolar glaciers to be used for recovering climate records of the Common Era, a period including pronounced anomalies such as the Little Ice Age and the Medieval Warm Period.
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6
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Multiple carbon cycle mechanisms associated with the glaciation of Marine Isotope Stage 4. Nat Commun 2022; 13:5443. [PMID: 36114188 PMCID: PMC9481522 DOI: 10.1038/s41467-022-33166-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 09/02/2022] [Indexed: 12/01/2022] Open
Abstract
Here we use high-precision carbon isotope data (δ13C-CO2) to show atmospheric CO2 during Marine Isotope Stage 4 (MIS 4, ~70.5-59 ka) was controlled by a succession of millennial-scale processes. Enriched δ13C-CO2 during peak glaciation suggests increased ocean carbon storage. Variations in δ13C-CO2 in early MIS 4 suggest multiple processes were active during CO2 drawdown, potentially including decreased land carbon and decreased Southern Ocean air-sea gas exchange superposed on increased ocean carbon storage. CO2 remained low during MIS 4 while δ13C-CO2 fluctuations suggest changes in Southern Ocean and North Atlantic air-sea gas exchange. A 7 ppm increase in CO2 at the onset of Dansgaard-Oeschger event 19 (72.1 ka) and 27 ppm increase in CO2 during late MIS 4 (Heinrich Stadial 6, ~63.5-60 ka) involved additions of isotopically light carbon to the atmosphere. The terrestrial biosphere and Southern Ocean air-sea gas exchange are possible sources, with the latter event also involving decreased ocean carbon storage. Summary for general audience: We used carbon stable isotope data from an Antarctic ice core to evaluate which mechanisms caused changes in atmospheric carbon dioxide 74-59 thousand years ago, including a ~40 ppm decrease at the beginning of the last ice age.
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Zhang Q, Qi Y, Pan H, Tang H, Wang G, Hua X, Wang Y, Lin L, Li Z, Li Y, Yu F, Yu Z, Huang Y, Wang T, Ma P, Dou M, Sun Z, Wang Y, Wang H, Zhang X, Yao W, Wang Y, Liu X, Wang M, Wang J, Deng Z, Xu J, Yang Q, Liu Z, Chen B, Zhang M, Ming R, Zhang J. Genomic insights into the recent chromosome reduction of autopolyploid sugarcane Saccharum spontaneum. Nat Genet 2022; 54:885-896. [PMID: 35654976 DOI: 10.1038/s41588-022-01084-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 04/26/2022] [Indexed: 01/30/2023]
Abstract
Saccharum spontaneum is a founding Saccharum species and exhibits wide variation in ploidy levels. We have assembled a high-quality autopolyploid genome of S. spontaneum Np-X (2n = 4x = 40) into 40 pseudochromosomes across 10 homologous groups, that better elucidates recent chromosome reduction and polyploidization that occurred circa 1.5 million years ago (Mya). One paleo-duplicated chromosomal pair in Saccharum, NpChr5 and NpChr8, underwent fission followed by fusion accompanied by centromeric split around 0.80 Mya. We inferred that Np-X, with x = 10, most likely represents the ancestral karyotype, from which x = 9 and x = 8 evolved. Resequencing of 102 S. spontaneum accessions revealed that S. spontaneum originated in northern India from an x = 10 ancestor, which then radiated into four major groups across the Indian subcontinent, China, and Southeast Asia. Our study suggests new directions for accelerating sugarcane improvement and expands our knowledge of the evolution of autopolyploids.
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Affiliation(s)
- Qing Zhang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yiying Qi
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Haoran Pan
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Haibao Tang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Gang Wang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiuting Hua
- Guangxi Key Lab for Sugarcane Biology, Guangxi University, Nanning, China
| | - Yongjun Wang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Lianyu Lin
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhen Li
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Yihan Li
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Fan Yu
- Guangxi Key Lab for Sugarcane Biology, Guangxi University, Nanning, China
| | - Zehuai Yu
- Guangxi Key Lab for Sugarcane Biology, Guangxi University, Nanning, China
| | - Yongji Huang
- Institute of Oceanography, Marine Biotechnology Center, Minjiang University, Fuzhou, China
| | - Tianyou Wang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Panpan Ma
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Meijie Dou
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | | | - Yibin Wang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hengbo Wang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xingtan Zhang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Wei Yao
- Guangxi Key Lab for Sugarcane Biology, Guangxi University, Nanning, China
| | - Yuntong Wang
- Biomarker Technologies Corporation, Beijing, China
| | - Xinlong Liu
- Yunnan Key Laboratory of Sugarcane Genetic Improvement, Sugarcane Research Institute, Yunnan Academy of Agricultural Sciences, Kaiyuan, China
| | - Maojun Wang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Jianping Wang
- Department of Agronomy, University of Florida, Gainesville, FL, USA
| | - Zuhu Deng
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jingsheng Xu
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Qinghui Yang
- Sugarcane Research Institute, Yunnan Agricultural University, Kunming, China
| | - ZhongJian Liu
- Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization at College of Landscape Architecture, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Baoshan Chen
- Guangxi Key Lab for Sugarcane Biology, Guangxi University, Nanning, China
| | - Muqing Zhang
- Guangxi Key Lab for Sugarcane Biology, Guangxi University, Nanning, China
| | - Ray Ming
- Department of Plant Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Jisen Zhang
- Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Sugarcane Biology and Genetic Breeding, National Engineering Research Center for Sugarcane, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.
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8
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Bagniewski W, Ghil M, Rousseau DD. Automatic detection of abrupt transitions in paleoclimate records. CHAOS (WOODBURY, N.Y.) 2021; 31:113129. [PMID: 34881579 DOI: 10.1063/5.0062543] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 10/08/2021] [Indexed: 06/13/2023]
Abstract
Bifurcations and tipping points (TPs) are an important part of the Earth system's behavior. These critical points represent thresholds at which small changes in the system's parameters or in the forcing abruptly switch it from one state or type of behavior to another. Current concern with TPs is largely due to the potential of slow anthropogenic forcing to bring about abrupt, and possibly irreversible, change to the physical climate system and impacted ecosystems. Paleoclimate proxy records have been shown to contain abrupt transitions, or "jumps," which may represent former instances of such dramatic climate change events. These transitions can provide valuable information for identifying critical TPs in current and future climate evolution. Here, we present a robust methodology for detecting abrupt transitions in proxy records that is applied to ice core and speleothem records of the last climate cycle. This methodology is based on the nonparametric Kolmogorov-Smirnov (KS) test for the equality, or not, of the probability distributions associated with two samples drawn from a time series, before and after any potential jump. To improve the detection of abrupt transitions in proxy records, the KS test is augmented by several other criteria and it is compared with recurrence analysis. The augmented KS test results show substantial skill when compared with more subjective criteria for jump detection. This test can also usefully complement recurrence analysis and improve upon certain aspects of its results.
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Affiliation(s)
- W Bagniewski
- Department of Geosciences and Laboratoire de Météorologie Dynamique (CNRS and IPSL), École Normale Supérieure and PSL University, 75132 Paris Cedex 05, France
| | - M Ghil
- Department of Geosciences and Laboratoire de Météorologie Dynamique (CNRS and IPSL), École Normale Supérieure and PSL University, 75132 Paris Cedex 05, France
| | - D D Rousseau
- Geosciences Montpellier, University of Montpellier, CNRS, 34095 Montpellier, France
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9
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Buizert C, Fudge TJ, Roberts WHG, Steig EJ, Sherriff-Tadano S, Ritz C, Lefebvre E, Edwards J, Kawamura K, Oyabu I, Motoyama H, Kahle EC, Jones TR, Abe-Ouchi A, Obase T, Martin C, Corr H, Severinghaus JP, Beaudette R, Epifanio JA, Brook EJ, Martin K, Chappellaz J, Aoki S, Nakazawa T, Sowers TA, Alley RB, Ahn J, Sigl M, Severi M, Dunbar NW, Svensson A, Fegyveresi JM, He C, Liu Z, Zhu J, Otto-Bliesner BL, Lipenkov VY, Kageyama M, Schwander J. Antarctic surface temperature and elevation during the Last Glacial Maximum. Science 2021; 372:1097-1101. [PMID: 34083489 DOI: 10.1126/science.abd2897] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 04/29/2021] [Indexed: 11/02/2022]
Abstract
Water-stable isotopes in polar ice cores are a widely used temperature proxy in paleoclimate reconstruction, yet calibration remains challenging in East Antarctica. Here, we reconstruct the magnitude and spatial pattern of Last Glacial Maximum surface cooling in Antarctica using borehole thermometry and firn properties in seven ice cores. West Antarctic sites cooled ~10°C relative to the preindustrial period. East Antarctic sites show a range from ~4° to ~7°C cooling, which is consistent with the results of global climate models when the effects of topographic changes indicated with ice core air-content data are included, but less than those indicated with the use of water-stable isotopes calibrated against modern spatial gradients. An altered Antarctic temperature inversion during the glacial reconciles our estimates with water-isotope observations.
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Affiliation(s)
- Christo Buizert
- College of Earth Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.
| | - T J Fudge
- Department of Earth and Space Science, University of Washington, Seattle, WA 98195, USA
| | - William H G Roberts
- Geographical and Environmental Sciences, Northumbria University, Newcastle, UK
| | - Eric J Steig
- Department of Earth and Space Science, University of Washington, Seattle, WA 98195, USA
| | - Sam Sherriff-Tadano
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8568, Japan
| | - Catherine Ritz
- Université Grenoble Alpes, CNRS, IRD, IGE, Grenoble, France
| | - Eric Lefebvre
- Université Grenoble Alpes, CNRS, IRD, IGE, Grenoble, France
| | - Jon Edwards
- College of Earth Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Kenji Kawamura
- National Institute of Polar Research, Tachikawa, Tokyo, Japan.,Department of Polar Science, The Graduate University of Advanced Studies (SOKENDAI), Tokyo, Japan.,Japan Agency for Marine Science and Technology (JAMSTEC), Yokosuka, Japan
| | - Ikumi Oyabu
- National Institute of Polar Research, Tachikawa, Tokyo, Japan
| | | | - Emma C Kahle
- Department of Earth and Space Science, University of Washington, Seattle, WA 98195, USA
| | - Tyler R Jones
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
| | - Ayako Abe-Ouchi
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8568, Japan
| | - Takashi Obase
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8568, Japan
| | | | - Hugh Corr
- British Antarctic Survey, Cambridge, UK
| | - Jeffrey P Severinghaus
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - Ross Beaudette
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093, USA
| | - Jenna A Epifanio
- College of Earth Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Edward J Brook
- College of Earth Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Kaden Martin
- College of Earth Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | | | - Shuji Aoki
- Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Takakiyo Nakazawa
- Center for Atmospheric and Oceanic Studies, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan
| | - Todd A Sowers
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, South Korea
| | - Richard B Alley
- The Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA 16802, USA
| | - Jinho Ahn
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, South Korea
| | - Michael Sigl
- Climate and Environmental Physics, Physics Institute & Oeschger Center for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Mirko Severi
- Department of Chemistry "Ugo Schiff," University of Florence, Florence, Italy.,Institute of Polar Sciences, ISP-CNR, Venice-Mestre, Italy
| | - Nelia W Dunbar
- New Mexico Bureau of Geology & Mineral Resources, Earth and Environmental Science Department, New Mexico Tech, Socorro, NM 87801, USA
| | - Anders Svensson
- Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
| | - John M Fegyveresi
- School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA
| | - Chengfei He
- Department of Geography, Ohio State University, Columbus, OH 43210, USA
| | - Zhengyu Liu
- Department of Geography, Ohio State University, Columbus, OH 43210, USA
| | - Jiang Zhu
- National Center for Atmospheric Research, Boulder, CO 80307, USA
| | | | - Vladimir Y Lipenkov
- Climate and Environmental Research Laboratory, Arctic and Antarctic Research Institute, St. Petersburg 199397, Russia
| | - Masa Kageyama
- Laboratoire des Sciences du Climat et de l'Environnement-IPSL, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Jakob Schwander
- Climate and Environmental Physics, Physics Institute & Oeschger Center for Climate Change Research, University of Bern, 3012 Bern, Switzerland
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10
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He C, Liu Z, Otto-Bliesner BL, Brady EC, Zhu C, Tomas R, Buizert C, Severinghaus JP. Abrupt Heinrich Stadial 1 cooling missing in Greenland oxygen isotopes. SCIENCE ADVANCES 2021; 7:7/25/eabh1007. [PMID: 34134984 PMCID: PMC8208719 DOI: 10.1126/sciadv.abh1007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 04/29/2021] [Indexed: 05/10/2023]
Abstract
Abrupt climate changes during the last deglaciation have been well preserved in proxy records across the globe. However, one long-standing puzzle is the apparent absence of the onset of the Heinrich Stadial 1 (HS1) cold event around 18 ka in Greenland ice core oxygen isotope δ18 O records, inconsistent with other proxies. Here, combining proxy records with an isotope-enabled transient deglacial simulation, we propose that a substantial HS1 cooling onset did indeed occur over the Arctic in winter. However, this cooling signal in the depleted oxygen isotopic composition is completely compensated by the enrichment because of the loss of winter precipitation in response to sea ice expansion associated with AMOC slowdown during extreme glacial climate. In contrast, the Arctic summer warmed during HS1 and YD because of increased insolation and greenhouse gases, consistent with snowline reconstructions. Our work suggests that Greenland δ18 O may substantially underestimate temperature variability during cold glacial conditions.
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Affiliation(s)
- Chengfei He
- College of Atmospheric Sciences, Nanjing University of Information Science and Technology, Nanjing, China
- Department of Geography, The Ohio State University, Columbus, OH 43210, USA
- Open Studio for Ocean-Climate-Isotope Modeling, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
| | - Zhengyu Liu
- Department of Geography, The Ohio State University, Columbus, OH 43210, USA.
- College of Geography Sciences, Nanjing Normal University, Nanjing, China
| | - Bette L Otto-Bliesner
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Esther C Brady
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Chenyu Zhu
- Open Studio for Ocean-Climate-Isotope Modeling, Pilot National Laboratory for Marine Science and Technology, Qingdao, China
- Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao, China
| | - Robert Tomas
- Climate and Global Dynamics Laboratory, National Center for Atmospheric Research, Boulder, CO 80305, USA
| | - Christo Buizert
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Jeffrey P Severinghaus
- Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92037, USA
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11
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Sun N, Brandon AD, Forman SL, Waters MR, Befus KS. Volcanic origin for Younger Dryas geochemical anomalies ca. 12,900 cal B.P. SCIENCE ADVANCES 2020; 6:eaax8587. [PMID: 32789166 PMCID: PMC7399481 DOI: 10.1126/sciadv.aax8587] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 06/19/2020] [Indexed: 06/11/2023]
Abstract
The Younger Dryas (YD) abrupt cooling event ca. 12.9 ± 0.1 ka is associated with substantial meltwater input into the North Atlantic Ocean, reversing deglacial warming. One controversial and prevailing hypothesis is that a bolide impact or airburst is responsible for these environmental changes. Here, highly siderophile element (HSE; Os, Ir, Ru, Pt, Pd, and Re) abundances and 187Os/188Os ratios were obtained in a well-dated sediment section at Hall's Cave, TX, USA to test this hypothesis. In Hall's Cave, layers below, above, and in the YD have 187Os/188Os ratios consistent with incorporation of extraterrestrial or mantle-derived material. The HSE abundances indicate that these layers contain volcanic gas aerosols and not extraterrestrial materials. The most likely explanation is that episodic, distant volcanic emissions were deposited in Hall's Cave sediments. Coupled 187Os/188Os ratios and HSE concentration data at close stratigraphic intervals are required to effectively differentiate between bolide and volcanic origins.
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Affiliation(s)
- N. Sun
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77004, USA
| | - A. D. Brandon
- Department of Earth and Atmospheric Sciences, University of Houston, Houston, TX 77004, USA
| | - S. L. Forman
- Department of Geosciences, Baylor University, Waco, TX 76798, USA
| | - M. R. Waters
- Center for the Study of the First Americans, Department of Anthropology, Texas A&M University, College Station, TX 77843, USA
| | - K. S. Befus
- Department of Geosciences, Baylor University, Waco, TX 76798, USA
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12
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Burke KD, Williams JW, Brewer S, Finsinger W, Giesecke T, Lorenz DJ, Ordonez A. Differing climatic mechanisms control transient and accumulated vegetation novelty in Europe and eastern North America. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190218. [PMID: 31679485 DOI: 10.1098/rstb.2019.0218] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Understanding the mechanisms of climate that produce novel ecosystems is of joint interest to conservation biologists and palaeoecologists. Here, we define and differentiate transient from accumulated novelty and evaluate four climatic mechanisms proposed to cause species to reshuffle into novel assemblages: high climatic novelty, high spatial rates of change (displacement), high variance among displacement rates for individual climate variables, and divergence among displacement vector bearings. We use climate simulations to quantify climate novelty, displacement and divergence across Europe and eastern North America from the last glacial maximum to the present, and fossil pollen records to quantify vegetation novelty. Transient climate novelty is consistently the strongest predictor of transient vegetation novelty, while displacement rates (mean and variance) are equally important in Europe. However, transient vegetation novelty is lower in Europe and its relationship to climatic predictors is the opposite of expectation. For both continents, accumulated novelty is greater than transient novelty, and climate novelty is the strongest predictor of accumulated ecological novelty. These results suggest that controls on novel ecosystems vary with timescale and among continents, and that the twenty-first century emergence of novelty will be driven by both rapid rates of climate change and the emergence of novel climate states. This article is part of a discussion meeting issue 'The past is a foreign country: how much can the fossil record actually inform conservation?'
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Affiliation(s)
- Kevin D Burke
- Nelson Institute for Environmental Studies, University of Wisconsin-Madison, 550 N. Park Street, Madison, WI 53706, USA
| | - John W Williams
- Department of Geography, University of Wisconsin-Madison, 550 N. Park Street, Madison, WI 53706, USA.,Center for Climatic Research, University of Wisconsin-Madison, 550 N. Park Street, Madison, WI 53706, USA
| | - Simon Brewer
- Department of Geography, University of Utah, 260 S. Central Campus Drive, Salt Lake City, UT 84119, USA
| | - Walter Finsinger
- Palaeoecology, ISEM (UMR 5554 CNRS/UM/EPHE), Place E. Bataillon, 34095 Montpellier, France
| | - Thomas Giesecke
- Department of Palynology and Climate Dynamics, Albrecht-von-Haller-Institute for Plant Sciences, University of Göttingen, Untere Karspüle 2, 37073 Göttingen, Germany.,Department of Physical Geography, Faculty Geoscience, Utrecht University, PO Box 80115, 3508 TC Utrecht, The Netherlands
| | - David J Lorenz
- Center for Climatic Research, University of Wisconsin-Madison, 550 N. Park Street, Madison, WI 53706, USA
| | - Alejandro Ordonez
- Center for Biodiversity Dynamics in a Changing World and Ecoinformatics and Biodiversity, Department of Bioscience, Aarhus University, Ny Munkegade 116, 8000 Aarhus C, Denmark
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13
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Earth's radiative imbalance from the Last Glacial Maximum to the present. Proc Natl Acad Sci U S A 2019; 116:14881-14886. [PMID: 31285336 DOI: 10.1073/pnas.1905447116] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The energy imbalance at the top of the atmosphere determines the temporal evolution of the global climate, and vice versa changes in the climate system can alter the planetary energy fluxes. This interplay is fundamental to our understanding of Earth's heat budget and the climate system. However, even today, the direct measurement of global radiative fluxes is difficult, such that most assessments are based on changes in the total energy content of the climate system. We apply the same approach to estimate the long-term evolution of Earth's radiative imbalance in the past. New measurements of noble gas-derived mean ocean temperature from the European Project for Ice Coring in Antarctica Dome C ice core covering the last 40,000 y, combined with recent results from the West Antarctic Ice Sheet Divide ice core and the sea-level record, allow us to quantitatively reconstruct the history of the climate system energy budget. The temporal derivative of this quantity must be equal to the planetary radiative imbalance. During the deglaciation, a positive imbalance of typically +0.2 W⋅m-2 is maintained for ∼10,000 y, however, with two distinct peaks that reach up to 0.4 W⋅m-2 during times of substantially reduced Atlantic Meridional Overturning Circulation. We conclude that these peaks are related to net changes in ocean heat uptake, likely due to rapid changes in North Atlantic deep-water formation and their impact on the global radiative balance, while changes in cloud coverage, albeit uncertain, may also factor into the picture.
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14
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Datema M, Sangiorgi F, de Vernal A, Reichart G, Lourens LJ, Sluijs A. Millennial-Scale Climate Variability and Dinoflagellate-Cyst-Based Seasonality Changes Over the Last ~150 kyrs at "Shackleton Site" U1385. PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY 2019; 34:1139-1156. [PMID: 31598587 PMCID: PMC6774308 DOI: 10.1029/2018pa003497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 05/03/2019] [Accepted: 05/15/2019] [Indexed: 06/10/2023]
Abstract
During the last glacial period, climate conditions in the North Atlantic region were determined by the alternation of relatively warm interstadials and relatively cool stadials, with superimposed rapid warming (Dansgaard-Oeschger) and cooling (Heinrich) events. So far little is known about the impact of these rapid climate shifts on the seasonal variations in sea surface temperature (SST) within the North Atlantic region. Here, we present a high-resolution seasonal SST record for the past 152 kyrs derived from Integrated Ocean Drilling Program "Shackleton" Site U1385, offshore Portugal. Assemblage counts of dinoflagellates cysts (dinocysts) in combination with a modern analog technique (MAT), and regression analyses were used for the reconstructions. We compare our records with previously published SST records from the same location obtained from the application of MAT on planktonic foraminifera. Our dinocyst-based reconstructions confirm the impression of the Greenland stadials and interstadials offshore the Portuguese margin and indicate increased seasonal contrast of temperature during the cold periods of the glacial cycle (average 9.0 °C, maximum 12.2 °C) with respect to present day (5.1 °C), due to strong winter cooling by up to 8.3 °C. Our seasonal temperature reconstructions are in line with previously published data, which showed increased seasonality due to strong winter cooling during the Younger Dryas and the Last Glacial Maximum over the European continent and North Atlantic region. In addition, we show that over longer time scales, increased seasonal contrasts of temperature remained characteristic of the colder phases of the glacial cycle.
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Affiliation(s)
- Mariska Datema
- Marine Palynology and Paleoceanography, Laboratory of Palaeobotany and Palynology, Department of Earth Sciences, Faculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
| | - Francesca Sangiorgi
- Marine Palynology and Paleoceanography, Laboratory of Palaeobotany and Palynology, Department of Earth Sciences, Faculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
| | - Anne de Vernal
- Centre de recherche en géochimie et géodynamique (Geotop)Université du Québec à MontréalMontréalQuebecCanada
| | - Gert‐Jan Reichart
- Department of Earth Sciences, Faculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
- Department of Ocean SystemsNIOZ Royal Netherlands Institute for Sea ResearchTexelThe Netherlands
| | - Lucas J. Lourens
- Department of Earth Sciences, Faculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
| | - Appy Sluijs
- Marine Palynology and Paleoceanography, Laboratory of Palaeobotany and Palynology, Department of Earth Sciences, Faculty of GeosciencesUtrecht UniversityUtrechtThe Netherlands
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15
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Zhao M, Sun B, Wu L, Wang F, Wen C, Wang M, Liang Y, Hale L, Zhou J, Yang Y. Dissimilar responses of fungal and bacterial communities to soil transplantation simulating abrupt climate changes. Mol Ecol 2019; 28:1842-1856. [DOI: 10.1111/mec.15053] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 02/02/2019] [Accepted: 02/11/2019] [Indexed: 12/12/2022]
Affiliation(s)
- Mengxin Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection Chinese Academy of Agricultural Sciences Beijing China
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment Tsinghua University Beijing China
| | - Bo Sun
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences Nanjing China
| | - Linwei Wu
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment Tsinghua University Beijing China
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences University of Oklahoma Norman Oklahoma
| | - Feng Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences Nanjing China
- Ningbo Academy of Agricultural Sciences Ningbo China
| | - Chongqing Wen
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences University of Oklahoma Norman Oklahoma
- Fisheries College Guangdong Ocean University Zhanjiang China
| | - Mengmeng Wang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment Tsinghua University Beijing China
| | - Yuting Liang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science Chinese Academy of Sciences Nanjing China
| | - Lauren Hale
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences University of Oklahoma Norman Oklahoma
| | - Jizhong Zhou
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment Tsinghua University Beijing China
- Institute for Environmental Genomics, Department of Microbiology and Plant Biology, and School of Civil Engineering and Environmental Sciences University of Oklahoma Norman Oklahoma
- Earth and Environmental Sciences Lawrence Berkeley National Laboratory Berkeley California
| | - Yunfeng Yang
- State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment Tsinghua University Beijing China
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16
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Mean global ocean temperatures during the last glacial transition. Nature 2018; 553:39-44. [PMID: 29300008 DOI: 10.1038/nature25152] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 11/17/2017] [Indexed: 11/08/2022]
Abstract
Little is known about the ocean temperature's long-term response to climate perturbations owing to limited observations and a lack of robust reconstructions. Although most of the anthropogenic heat added to the climate system has been taken up by the ocean up until now, its role in a century and beyond is uncertain. Here, using noble gases trapped in ice cores, we show that the mean global ocean temperature increased by 2.57 ± 0.24 degrees Celsius over the last glacial transition (20,000 to 10,000 years ago). Our reconstruction provides unprecedented precision and temporal resolution for the integrated global ocean, in contrast to the depth-, region-, organism- and season-specific estimates provided by other methods. We find that the mean global ocean temperature is closely correlated with Antarctic temperature and has no lead or lag with atmospheric CO2, thereby confirming the important role of Southern Hemisphere climate in global climate trends. We also reveal an enigmatic 700-year warming during the early Younger Dryas period (about 12,000 years ago) that surpasses estimates of modern ocean heat uptake.
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17
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Kobashi T, Menviel L, Jeltsch-Thömmes A, Vinther BM, Box JE, Muscheler R, Nakaegawa T, Pfister PL, Döring M, Leuenberger M, Wanner H, Ohmura A. Volcanic influence on centennial to millennial Holocene Greenland temperature change. Sci Rep 2017; 7:1441. [PMID: 28469185 PMCID: PMC5431187 DOI: 10.1038/s41598-017-01451-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/30/2017] [Indexed: 11/23/2022] Open
Abstract
Solar variability has been hypothesized to be a major driver of North Atlantic millennial-scale climate variations through the Holocene along with orbitally induced insolation change. However, another important climate driver, volcanic forcing has generally been underestimated prior to the past 2,500 years partly owing to the lack of proper proxy temperature records. Here, we reconstruct seasonally unbiased and physically constrained Greenland Summit temperatures over the Holocene using argon and nitrogen isotopes within trapped air in a Greenland ice core (GISP2). We show that a series of volcanic eruptions through the Holocene played an important role in driving centennial to millennial-scale temperature changes in Greenland. The reconstructed Greenland temperature exhibits significant millennial correlations with K+ and Na+ ions in the GISP2 ice core (proxies for atmospheric circulation patterns), and δ18O of Oman and Chinese Dongge cave stalagmites (proxies for monsoon activity), indicating that the reconstructed temperature contains hemispheric signals. Climate model simulations forced with the volcanic forcing further suggest that a series of large volcanic eruptions induced hemispheric-wide centennial to millennial-scale variability through ocean/sea-ice feedbacks. Therefore, we conclude that volcanic activity played a critical role in driving centennial to millennial-scale Holocene temperature variability in Greenland and likely beyond.
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Affiliation(s)
- Takuro Kobashi
- Climate and Environmental Physics, University of Bern, 3012, Bern, Switzerland. .,Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland. .,Renewable Energy Institute, Minato-ku, 105-0003, Tokyo, Japan.
| | - Laurie Menviel
- Climate Change Research Centre and PANGEA Research Centre, University of New South Wales, New South Wales, 2052, Australia.,ARC Centre of Excellence for Climate System Science, New South Wales, Sydney, Australia
| | - Aurich Jeltsch-Thömmes
- Climate and Environmental Physics, University of Bern, 3012, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Bo M Vinther
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Jason E Box
- Geological Survey of Greenland and Denmark, 1350, Copenhagen, Denmark
| | - Raimund Muscheler
- Department of Geology, Quaternary Sciences, Lund University, 22362, Lund, Sweden
| | | | - Patrik L Pfister
- Climate and Environmental Physics, University of Bern, 3012, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Michael Döring
- Climate and Environmental Physics, University of Bern, 3012, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Markus Leuenberger
- Climate and Environmental Physics, University of Bern, 3012, Bern, Switzerland.,Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Heinz Wanner
- Oeschger Centre for Climate Change Research, University of Bern, 3012, Bern, Switzerland
| | - Atsumu Ohmura
- Institute for Atmospheric and Climate Science, Swiss Federal Institute of Technology ETH Zurich, 8092, Zurich, Switzerland
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18
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Stolper DA, Bender ML, Dreyfus GB, Yan Y, Higgins JA. A Pleistocene ice core record of atmospheric O2 concentrations. Science 2017; 353:1427-1430. [PMID: 27708037 DOI: 10.1126/science.aaf5445] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 08/02/2016] [Indexed: 11/02/2022]
Abstract
The history of atmospheric O2 partial pressures (Po2) is inextricably linked to the coevolution of life and Earth's biogeochemical cycles. Reconstructions of past Po2 rely on models and proxies but often markedly disagree. We present a record of Po2 reconstructed using O2/N2 ratios from ancient air trapped in ice. This record indicates that Po2 declined by 7 per mil (0.7%) over the past 800,000 years, requiring that O2 sinks were ~2% larger than sources. This decline is consistent with changes in burial and weathering fluxes of organic carbon and pyrite driven by either Neogene cooling or increasing Pleistocene erosion rates. The 800,000-year record of steady average carbon dioxide partial pressures (Pco2) but declining Po2 provides distinctive evidence that a silicate weathering feedback stabilizes Pco2 on million-year time scales.
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Affiliation(s)
- D A Stolper
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - M L Bender
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA. Institute of Oceanology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - G B Dreyfus
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA. Laboratoire des Sciences du Climat et de l'Environnement, Gif-sur-Yvettte, France
| | - Y Yan
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
| | - J A Higgins
- Department of Geosciences, Princeton University, Princeton, NJ 08544, USA
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19
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Riehl S. The Role of the Local Environment in the Slow Pace of Emerging Agriculture in the Fertile Crescent. J ETHNOBIOL 2016. [DOI: 10.2993/0278-0771-36.3.512] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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20
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Buizert C, Gkinis V, Severinghaus JP, He F, Lecavalier BS, Kindler P, Leuenberger M, Carlson AE, Vinther B, Masson-Delmotte V, White JWC, Liu Z, Otto-Bliesner B, Brook EJ. Greenland temperature response to climate forcing during the last deglaciation. Science 2014; 345:1177-80. [PMID: 25190795 DOI: 10.1126/science.1254961] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Greenland ice core water isotopic composition (δ(18)O) provides detailed evidence for abrupt climate changes but is by itself insufficient for quantitative reconstruction of past temperatures and their spatial patterns. We investigate Greenland temperature evolution during the last deglaciation using independent reconstructions from three ice cores and simulations with a coupled ocean-atmosphere climate model. Contrary to the traditional δ(18)O interpretation, the Younger Dryas period was 4.5° ± 2°C warmer than the Oldest Dryas, due to increased carbon dioxide forcing and summer insolation. The magnitude of abrupt temperature changes is larger in central Greenland (9° to 14°C) than in the northwest (5° to 9°C), fingerprinting a North Atlantic origin. Simulated changes in temperature seasonality closely track changes in the Atlantic overturning strength and support the hypothesis that abrupt climate change is mostly a winter phenomenon.
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Affiliation(s)
- Christo Buizert
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.
| | - Vasileios Gkinis
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Denmark. Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
| | - Jeffrey P Severinghaus
- Scripps Institution of Oceanography, University of California-San Diego, La Jolla, CA 92093, USA
| | - Feng He
- Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin, Madison, WI 53706, USA
| | - Benoit S Lecavalier
- Department of Physics and Physical Oceanography, Memorial University, St. John's, Canada
| | - Philippe Kindler
- Division of Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Markus Leuenberger
- Division of Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Anders E Carlson
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - Bo Vinther
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Denmark
| | - Valérie Masson-Delmotte
- Laboratoire des Sciences du Climat et de l'Environnement, Institut Pierre Simon Laplace (UMR CEA-CNRS-UVSQ 8212), Gif-sur-Yvette, France
| | - James W C White
- Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309, USA
| | - Zhengyu Liu
- Center for Climatic Research, Nelson Institute for Environmental Studies, University of Wisconsin, Madison, WI 53706, USA. Laboratory for Climate and Ocean-Atmosphere Studies, Peking University, Beijing 100871, China
| | - Bette Otto-Bliesner
- Climate and Global Dynamics Division, National Center for Atmospheric Research, Boulder, CO 80307, USA
| | - Edward J Brook
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
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21
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Abstract
The Younger Dryas Stadial (YDS; ∼ 12,900-11,600 y ago) in the Northern Hemisphere is classically defined by abrupt cooling and renewed glaciation during the last glacial-interglacial transition. Although this event involved a global reorganization of atmospheric and oceanic circulation [Denton GH, Alley RB, Comer GC, Broecker WS (2005) Quat Sci Rev 24:1159-1182], the magnitude, seasonality, and geographical footprint of YDS cooling remain unresolved and pose a challenge to our understanding of abrupt climate change. Here, we present a deglacial chronology from Scotland, immediately downwind of the North Atlantic Ocean, indicating that the Scottish ice cap disintegrated during the first half of the YDS. We suggest that stratification of the North Atlantic Ocean resulted in amplified seasonality that, paradoxically, stimulated a severe wintertime climate while promoting warming summers through solar heating of the mixed layer. This latter process drove deglaciation of downwind landmasses to completion well before the end of the YDS.
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22
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Zimov S, Zimov N. Role of megafauna and frozen soil in the atmospheric CH4 dynamics. PLoS One 2014; 9:e93331. [PMID: 24695117 PMCID: PMC3973675 DOI: 10.1371/journal.pone.0093331] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 03/05/2014] [Indexed: 11/19/2022] Open
Abstract
Modern wetlands are the world’s strongest methane source. But what was the role of this source in the past? An analysis of global 14C data for basal peat combined with modelling of wetland succession allowed us to reconstruct the dynamics of global wetland methane emission through time. These data show that the rise of atmospheric methane concentrations during the Pleistocene-Holocene transition was not connected with wetland expansion, but rather started substantially later, only 9 thousand years ago. Additionally, wetland expansion took place against the background of a decline in atmospheric methane concentration. The isotopic composition of methane varies according to source. Owing to ice sheet drilling programs past dynamics of atmospheric methane isotopic composition is now known. For example over the course of Pleistocene-Holocene transition atmospheric methane became depleted in the deuterium isotope, which indicated that the rise in methane concentrations was not connected with activation of the deuterium-rich gas clathrates. Modelling of the budget of the atmospheric methane and its isotopic composition allowed us to reconstruct the dynamics of all main methane sources. For the late Pleistocene, the largest methane source was megaherbivores, whose total biomass is estimated to have exceeded that of present-day humans and domestic animals. This corresponds with our independent estimates of herbivore density on the pastures of the late Pleistocene based on herbivore skeleton density in the permafrost. During deglaciation, the largest methane emissions originated from degrading frozen soils of the mammoth steppe biome. Methane from this source is unique, as it is depleted of all isotopes. We estimated that over the entire course of deglaciation (15,000 to 6,000 year before present), soils of the mammoth steppe released 300–550 Pg (1015 g) of methane. From current study we conclude that the Late Quaternary Extinction significantly affected the global methane cycle.
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Affiliation(s)
- Sergey Zimov
- Northeast Science Station, Pacific Institute for Geography, Russian Academy of Sciences, Cherskii, Russia
- * E-mail:
| | - Nikita Zimov
- Northeast Science Station, Pacific Institute for Geography, Russian Academy of Sciences, Cherskii, Russia
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23
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Metcalf JL, Prost S, Nogués-Bravo D, DeChaine EG, Anderson C, Batra P, Araújo MB, Cooper A, Guralnick RP. Integrating multiple lines of evidence into historical biogeography hypothesis testing: a Bison bison case study. Proc Biol Sci 2014; 281:20132782. [PMID: 24403338 PMCID: PMC3896022 DOI: 10.1098/rspb.2013.2782] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 12/04/2013] [Indexed: 01/30/2023] Open
Abstract
One of the grand goals of historical biogeography is to understand how and why species' population sizes and distributions change over time. Multiple types of data drawn from disparate fields, combined into a single modelling framework, are necessary to document changes in a species's demography and distribution, and to determine the drivers responsible for change. Yet truly integrated approaches are challenging and rarely performed. Here, we discuss a modelling framework that integrates spatio-temporal fossil data, ancient DNA, palaeoclimatological reconstructions, bioclimatic envelope modelling and coalescence models in order to statistically test alternative hypotheses of demographic and potential distributional changes for the iconic American bison (Bison bison). Using different assumptions about the evolution of the bioclimatic niche, we generate hypothetical distributional and demographic histories of the species. We then test these demographic models by comparing the genetic signature predicted by serial coalescence against sequence data derived from subfossils and modern populations. Our results supported demographic models that include both climate and human-associated drivers of population declines. This synthetic approach, integrating palaeoclimatology, bioclimatic envelopes, serial coalescence, spatio-temporal fossil data and heterochronous DNA sequences, improves understanding of species' historical biogeography by allowing consideration of both abiotic and biotic interactions at the population level.
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Affiliation(s)
- Jessica L. Metcalf
- Australian Centre for Ancient DNA, University of Adelaide, Adelaide, South Australia, Australia
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO, USA
| | - Stefan Prost
- Allan Wilson Centre for Molecular Ecology and Evolution, University of Otago, Dunedin, New Zealand
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - David Nogués-Bravo
- Center for Macroecology, Evolution, and Climate, University of Copenhagen, Copenhagen, Denmark
| | - Eric G. DeChaine
- Department of Biology, Western Washington University, Bellingham, WA, USA
| | - Christian Anderson
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Persaram Batra
- Department of Geology, Greenfield Community College, Greenfield, MA, USA
| | - Miguel B. Araújo
- Center for Macroecology, Evolution, and Climate, University of Copenhagen, Copenhagen, Denmark
- Department of Biodiversity and Evolutionary Biology, Museo Nacional de Ciencias Naturales, CSIC, Madrid, Spain
- Imperial College London, Silwood Park Campus, Berkshire, UK
| | - Alan Cooper
- Australian Centre for Ancient DNA, University of Adelaide, Adelaide, South Australia, Australia
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El Zaatari S, Hublin JJ. Diet of upper paleolithic modern humans: evidence from microwear texture analysis. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2014; 153:570-81. [PMID: 24449141 DOI: 10.1002/ajpa.22457] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 12/12/2013] [Indexed: 11/09/2022]
Abstract
This article presents the results of the occlusal molar microwear texture analysis of 32 adult Upper Paleolithic modern humans from a total of 21 European sites dating to marine isotope stages 3 and 2. The occlusal molar microwear textures of these specimens were analyzed with the aim of examining the effects of the climatic, as well as the cultural, changes on the diets of the Upper Paleolithic modern humans. The results of this analysis do not reveal any environmentally driven dietary shifts for the Upper Paleolithic hominins indicating that the climatic and their associated paleoecological changes did not force these humans to significantly alter their diets in order to survive. However, the microwear texture analysis does detect culturally related changes in the Upper Paleolithic humans' diets. Specifically, significant differences in diet were found between the earlier Upper Paleolithic individuals, i.e., those belonging to the Aurignacian and Gravettian contexts, and the later Magdalenian ones, such that the diet of the latter group was more varied and included more abrasive foods compared with those of the former.
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Affiliation(s)
- Sireen El Zaatari
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig D-04103, Germany; Department of Early Prehistory and Quaternary Ecology, Paleoanthropology, Senckenberg Center for Human Evolution and Paleoecology, Eberhard Karls University of Tübingen, Tübingen, 72070, Germany
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Orozco-terWengel P, Andreone F, Louis E, Vences M. Mitochondrial introgressive hybridization following a demographic expansion in the tomato frogs of Madagascar, genusDyscophus. Mol Ecol 2013; 22:6074-90. [DOI: 10.1111/mec.12558] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 10/06/2013] [Accepted: 10/07/2013] [Indexed: 01/01/2023]
Affiliation(s)
| | - Franco Andreone
- Museo Regionale di Scienze Naturali; Via Giolitti 36 10123 Torino Italy
| | - Edward Louis
- Omaha's Henry Doorly Zoo; 3701 S 10th Street Omaha NE 68107 USA
| | - Miguel Vences
- Division of Evolutionary Biology, Zoological Institute; Technical University of Braunschweig; Mendelssohnstr. 4 38106 Braunschweig Germany
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Onset of deglacial warming in West Antarctica driven by local orbital forcing. Nature 2013; 500:440-4. [PMID: 23945585 DOI: 10.1038/nature12376] [Citation(s) in RCA: 238] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 06/12/2013] [Indexed: 11/09/2022]
Abstract
The cause of warming in the Southern Hemisphere during the most recent deglaciation remains a matter of debate. Hypotheses for a Northern Hemisphere trigger, through oceanic redistributions of heat, are based in part on the abrupt onset of warming seen in East Antarctic ice cores and dated to 18,000 years ago, which is several thousand years after high-latitude Northern Hemisphere summer insolation intensity began increasing from its minimum, approximately 24,000 years ago. An alternative explanation is that local solar insolation changes cause the Southern Hemisphere to warm independently. Here we present results from a new, annually resolved ice-core record from West Antarctica that reconciles these two views. The records show that 18,000 years ago snow accumulation in West Antarctica began increasing, coincident with increasing carbon dioxide concentrations, warming in East Antarctica and cooling in the Northern Hemisphere associated with an abrupt decrease in Atlantic meridional overturning circulation. However, significant warming in West Antarctica began at least 2,000 years earlier. Circum-Antarctic sea-ice decline, driven by increasing local insolation, is the likely cause of this warming. The marine-influenced West Antarctic records suggest a more active role for the Southern Ocean in the onset of deglaciation than is inferred from ice cores in the East Antarctic interior, which are largely isolated from sea-ice changes.
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Hou S, Wang Y, Pang H. Climatology of stable isotopes in Antarctic snow and ice: Current status and prospects. CHINESE SCIENCE BULLETIN-CHINESE 2012. [DOI: 10.1007/s11434-012-5543-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Young NE, Briner JP, Rood DH, Finkel RC. Glacier Extent During the Younger Dryas and 8.2-ka Event on Baffin Island, Arctic Canada. Science 2012; 337:1330-3. [PMID: 22984068 DOI: 10.1126/science.1222759] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Nicolás E. Young
- Department of Geology, University at Buffalo, 411 Cooke Hall, Buffalo, NY 14260, USA
| | - Jason P. Briner
- Department of Geology, University at Buffalo, 411 Cooke Hall, Buffalo, NY 14260, USA
| | - Dylan H. Rood
- Accelerator Mass Spectrometry Laboratory, Scottish Universities Environmental Research Centre (SUERC), East Kilbride, UK
- Earth Research Institute, University of California, Santa Barbara, CA 93106, USA
| | - Robert C. Finkel
- Department of Earth and Planetary Sciences, University of California–Berkeley, Berkeley, CA 94720, USA
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Mialdun A, Yasnou V, Shevtsova V, Königer A, Köhler W, Alonso de Mezquia D, Bou-Ali MM. A comprehensive study of diffusion, thermodiffusion, and Soret coefficients of water-isopropanol mixtures. J Chem Phys 2012; 136:244512. [DOI: 10.1063/1.4730306] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
Greenland ice-core δ(18)O-temperature reconstructions suggest a dramatic cooling during the Younger Dryas (YD; 12.9-11.7 ka), with temperatures being as cold as the earlier Oldest Dryas (OD; 18.0-14.6 ka) despite an approximately 50 ppm rise in atmospheric CO(2). Such YD cooling implies a muted Greenland climate response to atmospheric CO(2), contrary to physical predictions of an enhanced high-latitude response to future increases in CO(2). Here we show that North Atlantic sea surface temperature reconstructions as well as transient climate model simulations suggest that the YD over Greenland should be substantially warmer than the OD by approximately 5 °C in response to increased atmospheric CO(2). Additional experiments with an isotope-enabled model suggest that the apparent YD temperature reconstruction derived from the ice-core δ(18)O record is likely an artifact of an altered temperature-δ(18)O relationship due to changing deglacial atmospheric circulation. Our results thus suggest that Greenland climate was warmer during the YD relative to the OD in response to rising atmospheric CO(2), consistent with sea surface temperature reconstructions and physical predictions, and has a sensitivity approximately twice that found in climate models for current climate due to an enhanced albedo feedback during the last deglaciation.
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Yang WH, Silver WL. Application of the N(2)/Ar technique to measuring soil-atmosphere N(2) fluxes. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2012; 26:449-459. [PMID: 22279021 DOI: 10.1002/rcm.6124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
RATIONALE The emission of dinitrogen (N(2) ) gas from soil is the most poorly constrained flux in terrestrial nitrogen (N) budgets because the high background atmospheric N(2) concentration makes soil N(2) emissions difficult to measure. In this study, we tested the theoretical and analytical feasibility of using the N(2) /Ar technique to measure soil-atmosphere N(2) fluxes. METHODS Dual inlet isotope ratio mass spectrometry was used to measure δAr/N(2) values of gas sampled from surface flux chambers. In laboratory experiments using dry sand in a diffusion box, we induced a known steady-state flux of N(2) , and then measured the change in the N(2) /Ar ratio of chamber headspace air samples to test our ability to reconstruct this flux. We m\odeled solubility, thermal, and water vapor flux fractionation effects on the N(2) /Ar ratio to constrain physical effects on the measured N(2) flux. RESULTS In dry sand, an actual N(2) flux of 108 mg N m(-2) day(-1) was measured as 111 ± 19 mg N m(-2) day(-1) (± standard error (SE)). In wet sand, an actual N(2) flux of 160 mg N m(-2) day(-1) was measured as 146 ± 20 mg N m(-2) day(-1) when solubility and water vapor flux fractionation were taken into account. Corrections for thermal fractionation did not improve estimates of N(2) fluxes. CONCLUSIONS We conclude that our application of the N(2) /Ar technique to soil surface fluxes is valid only above a detection limit of approximately 108 mg N m(-2) day(-1) . The N(2) /Ar method is currently best used as a validation tool for other methods in ecosystems with high soil N(2) fluxes, but, with future improvements, it holds promise to provide high-resolution measurements in systems with low soil N(2) fluxes.
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Affiliation(s)
- Wendy H Yang
- Ecosystem Sciences Division, Department of Environmental Science, Policy, and Management, 130 Mulford Hall #3114, University of California, Berkeley, CA 94720, USA.
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Brosius LS, Walter Anthony KM, Grosse G, Chanton JP, Farquharson LM, Overduin PP, Meyer H. Using the deuterium isotope composition of permafrost meltwater to constrain thermokarst lake contributions to atmospheric CH4during the last deglaciation. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jg001810] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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de Bruyn M, Hoelzel AR, Carvalho GR, Hofreiter M. Faunal histories from Holocene ancient DNA. Trends Ecol Evol 2011; 26:405-13. [PMID: 21529992 DOI: 10.1016/j.tree.2011.03.021] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Revised: 03/24/2011] [Accepted: 03/28/2011] [Indexed: 02/05/2023]
Abstract
Recent studies using ancient DNA have been instrumental in advancing understanding of the impact of Holocene climate change on biodiversity. Ancient DNA has been used to track demography, migration and diversity, and is providing new insights into the long-term dynamics of species and population distributions. The Holocene is key to understanding how the past has impacted on the present, as it bridges the gap between contemporary phylogeographic studies and those with inference on Pleistocene patterns, based on ancient DNA studies. Here, we examine the major patterns of Holocene faunal population dynamics and connectivity; highlighting the dynamic nature of species and population responses to Holocene climatic change, thereby providing an 'analogue' for understanding potential impacts of future change.
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Affiliation(s)
- Mark de Bruyn
- Molecular Ecology & Fisheries Genetics Laboratory, Environment Centre for Wales, School of Biological Sciences, Bangor University, Bangor, UK, LL57 2UW.
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Wolff EW. Greenhouse gases in the Earth system: a palaeoclimate perspective. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2011; 369:2133-2147. [PMID: 21502180 DOI: 10.1098/rsta.2010.0225] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
While the trends in greenhouse gas concentrations in recent decades are clear, their significance is only revealed when viewed in the context of a longer time period. Fortunately, the air bubbles in polar ice cores provide an unusually direct method of determining the concentrations of stable gases over a period of (so far) 800,000 years. Measurements on different cores with varying characteristics, as well as an overlap of ice-core and atmospheric measurements covering the same time period, show that the ice-core record provides a faithful record of changing atmospheric composition. The mixing ratio of CO(2) is now 30 per cent higher than any value observed in the ice-core record, while methane is more than double any observed value; the rate of change also appears extraordinary compared with natural changes. Before the period when anthropogenic changes have dominated, there are very interesting natural changes in concentration, particularly across glacial/interglacial cycles, and these can be used to understand feedbacks in the Earth system. The phasing of changes in temperature and CO(2) across glacial/interglacial transitions is consistent with the idea that CO(2) acts as an important amplifier of climate changes in the natural system. Even larger changes are inferred to have occurred in periods earlier than the ice cores cover, and these events might be used to constrain assessments of the way the Earth could respond to higher than present concentrations of CO(2), and to a large release of carbon: however, more certainty about CO(2) concentrations beyond the time period covered by ice cores is needed before such constraints can be fully realized.
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Affiliation(s)
- Eric W Wolff
- British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK.
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36
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Mitchell LE, Brook EJ, Sowers T, McConnell JR, Taylor K. Multidecadal variability of atmospheric methane, 1000–1800 C.E. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jg001441] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hill JK, Griffiths HM, Thomas CD. Climate change and evolutionary adaptations at species' range margins. ANNUAL REVIEW OF ENTOMOLOGY 2011; 56:143-59. [PMID: 20809802 DOI: 10.1146/annurev-ento-120709-144746] [Citation(s) in RCA: 136] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
During recent climate warming, many insect species have shifted their ranges to higher latitudes and altitudes. These expansions mirror those that occurred after the Last Glacial Maximum when species expanded from their ice age refugia. Postglacial range expansions have resulted in clines in genetic diversity across present-day distributions, with a reduction in genetic diversity observed in a wide range of insect taxa as one moves from the historical distribution core to the current range margin. Evolutionary increases in dispersal at expanding range boundaries are commonly observed in virtually all insects that have been studied, suggesting a positive feedback between range expansion and the evolution of traits that accelerate range expansion. The ubiquity of this phenomenon suggests that it is likely to be an important determinant of range changes. A better understanding of the extent and speed of adaptation will be crucial to the responses of biodiversity and ecosystems to climate change.
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Affiliation(s)
- Jane K Hill
- Department of Biology, University of York, YO10 5DD, United Kingdom.
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Kaplan MR, Schaefer JM, Denton GH, Barrell DJA, Chinn TJH, Putnam AE, Andersen BG, Finkel RC, Schwartz R, Doughty AM. Glacier retreat in New Zealand during the Younger Dryas stadial. Nature 2010; 467:194-7. [DOI: 10.1038/nature09313] [Citation(s) in RCA: 138] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Accepted: 06/22/2010] [Indexed: 11/09/2022]
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No evidence of nanodiamonds in Younger-Dryas sediments to support an impact event. Proc Natl Acad Sci U S A 2010; 107:16043-7. [PMID: 20805511 DOI: 10.1073/pnas.1003904107] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The causes of the late Pleistocene megafaunal extinctions in North America, disappearance of Clovis paleoindian lithic technology, and abrupt Younger-Dryas (YD) climate reversal of the last deglacial warming in the Northern Hemisphere remain an enigma. A controversial hypothesis proposes that one or more cometary airbursts/impacts barraged North America ≈12,900 cal yr B.P. and caused these events. Most evidence supporting this hypothesis has been discredited except for reports of nanodiamonds (including the rare hexagonal polytype) in Bølling-Ållerod-YD-boundary sediments. The hexagonal polytype of diamond, lonsdaleite, is of particular interest because it is often associated with shock pressures related to impacts where it has been found to occur naturally. Unfortunately, previous reports of YD-boundary nanodiamonds have left many unanswered questions regarding the nature and occurrence of the nanodiamonds. Therefore, we examined carbon-rich materials isolated from sediments dated 15,818 cal yr B.P. to present (including the Bølling-Allerod-YD boundary). No nanodiamonds were found in our study. Instead, graphene- and graphene/graphane-oxide aggregates are ubiquitous in all specimens examined. We demonstrate that previous studies misidentified graphene/graphane-oxide aggregates as hexagonal diamond and likely misidentified graphene as cubic diamond. Our results cast doubt upon one of the last widely discussed pieces of evidence supporting the YD impact hypothesis.
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Denton GH, Anderson RF, Toggweiler JR, Edwards RL, Schaefer JM, Putnam AE. The last glacial termination. Science 2010; 328:1652-6. [PMID: 20576882 DOI: 10.1126/science.1184119] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A major puzzle of paleoclimatology is why, after a long interval of cooling climate, each late Quaternary ice age ended with a relatively short warming leg called a termination. We here offer a comprehensive hypothesis of how Earth emerged from the last global ice age. A prerequisite was the growth of very large Northern Hemisphere ice sheets, whose subsequent collapse created stadial conditions that disrupted global patterns of ocean and atmospheric circulation. The Southern Hemisphere westerlies shifted poleward during each northern stadial, producing pulses of ocean upwelling and warming that together accounted for much of the termination in the Southern Ocean and Antarctica. Rising atmospheric CO2 during southern upwelling pulses augmented warming during the last termination in both polar hemispheres.
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Affiliation(s)
- G H Denton
- Department of Earth Sciences and Climate Change Institute, Bryand Global Sciences Center, University of Maine, Orono, ME 04469, USA
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42
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Isotope fractionation in silicate melts by thermal diffusion. Nature 2010; 464:396-400. [PMID: 20237567 DOI: 10.1038/nature08840] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Accepted: 01/13/2010] [Indexed: 11/09/2022]
Abstract
The phenomenon of thermal diffusion (mass diffusion driven by a temperature gradient, known as the Ludwig-Soret effect) has been investigated for over 150 years, but an understanding of its underlying physical basis remains elusive. A significant hurdle in studying thermal diffusion has been the difficulty of characterizing it. Extensive experiments over the past century have established that the Soret coefficient, S(T) (a single parameter that describes the steady-state result of thermal diffusion), is highly sensitive to many factors. This sensitivity makes it very difficult to obtain a robust characterization of thermal diffusion, even for a single material. Here we show that for thermal diffusion experiments that span a wide range in composition and temperature, the difference in S(T) between isotopes of diffusing elements that are network modifiers (iron, calcium and magnesium) is independent of the composition and temperature. On the basis of this finding, we propose an additive decomposition for the functional form of S(T) and argue that a theoretical approach based on local thermodynamic equilibrium holds promise for describing thermal diffusion in silicate melts and other complex solutions. Our results lead to a simple and robust framework for characterizing isotope fractionation by thermal diffusion in natural and synthetic systems.
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Affiliation(s)
- E. G. Nisbet
- Department of Earth Sciences, Royal Holloway, University of London, Egham TW20 0EX, UK
| | - J. Chappellaz
- Laboratoire de Glaciologie et Géophysique de l'Environnement, CNRS, University of Grenoble, BP 96, 38402 St. Martin d'Hères, France
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Thomas ER, Wolff EW, Mulvaney R, Johnsen SJ, Steffensen JP, Arrowsmith C. Anatomy of a Dansgaard‐Oeschger warming transition: High‐resolution analysis of the North Greenland Ice Core Project ice core. ACTA ACUST UNITED AC 2009. [DOI: 10.1029/2008jd011215] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sylvestre F. Moisture Pattern During the Last Glacial Maximum in South America. PAST CLIMATE VARIABILITY IN SOUTH AMERICA AND SURROUNDING REGIONS 2009. [DOI: 10.1007/978-90-481-2672-9_1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Abstract
Scientific knowledge of natural clathrate hydrates has grown enormously over the past decade, with spectacular new findings of large exposures of complex hydrates on the sea floor, the development of new tools for examining the solid phase in situ, significant progress in modeling natural hydrate systems, and the discovery of exotic hydrates associated with sea floor venting of liquid CO2. Major unresolved questions remain about the role of hydrates in response to climate change today, and correlations between the hydrate reservoir of Earth and the stable isotopic evidence of massive hydrate dissociation in the geologic past. The examination of hydrates as a possible energy resource is proceeding apace for the subpermafrost accumulations in the Arctic, but serious questions remain about the viability of marine hydrates as an economic resource. New and energetic explorations by nations such as India and China are quickly uncovering large hydrate findings on their continental shelves.
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Affiliation(s)
- Keith C Hester
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.
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47
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Reagan MT, Moridis GJ. Dynamic response of oceanic hydrate deposits to ocean temperature change. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008jc004938] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Matthew T. Reagan
- Earth Sciences Division; Lawrence Berkeley National Laboratory; Berkeley California USA
| | - George J. Moridis
- Earth Sciences Division; Lawrence Berkeley National Laboratory; Berkeley California USA
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Lee JE, Fung I, DePaolo DJ, Otto-Bliesner B. Water isotopes during the Last Glacial Maximum: New general circulation model calculations. ACTA ACUST UNITED AC 2008. [DOI: 10.1029/2008jd009859] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Knowledge of the outgassing history of radiogenic (40)Ar, derived over geologic time from the radioactive decay of (40)K, contributes to our understanding of the geodynamic history of the planet and the origin of volatiles on Earth's surface. The (40)Ar inventory of the atmosphere equals total (40)Ar outgassing during Earth history. Here, we report the current rate of (40)Ar outgassing, accessed by measuring the Ar isotope composition of trapped gases in samples of the Vostok and Dome C deep ice cores dating back to almost 800 ka. The modern outgassing rate (1.1 +/- 0.1 x 10(8) mol/yr) is in the range of values expected by summing outgassing from the continental crust and the upper mantle, as estimated from simple calculations and models. The measured outgassing rate is also of interest because it allows dating of air trapped in ancient ice core samples of unknown age, although uncertainties are large (+/-180 kyr for a single sample or +/-11% of the calculated age, whichever is greater).
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