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Ro S, Park J, Yoo H, Han C, Lee A, Lee Y, Kim M, Han Y, Svensson A, Shin J, Ro CU, Hong S. Millennial-scale variability of Greenland dust provenance during the last glacial maximum as determined by single particle analysis. Sci Rep 2024; 14:2040. [PMID: 38263283 PMCID: PMC10805741 DOI: 10.1038/s41598-024-52546-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 01/19/2024] [Indexed: 01/25/2024] Open
Abstract
Greenland ice core records exhibited 100-fold higher dust concentrations during the Last Glacial Maximum (LGM) than during the Holocene, and dust input temporal variability corresponded to different climate states in the LGM. While East Asian deserts, the Sahara, and European loess have been suggested as the potential source areas (PSAs) for Greenland LGM dust, millennial-scale variability in their relative contributions within the LGM remains poorly constrained. Here, we present the morphological, mineralogical, and geochemical characteristics of insoluble microparticles to constrain the provenance of dust in Greenland NEEM ice core samples covering cold Greenland Stadials (GS)-2.1a to GS-3 (~ 14.7 to 27.1 kyr ago) in the LGM. The analysis was conducted on individual particles in microdroplet samples by scanning electron microscopy with energy dispersive X-ray spectroscopy and Raman microspectroscopy. We found that the kaolinite-to-chlorite (K/C) ratios and chemical index of alteration (CIA) values were substantially higher (K/C: 1.4 ± 0.7, CIA: 74.7 ± 2.9) during GS-2.1a to 2.1c than during GS-3 (K/C: 0.5 ± 0.1, CIA: 65.8 ± 2.8). Our records revealed a significant increase in Saharan dust contributions from GS-2.1a to GS-2.1c and that the Gobi Desert and/or European loess were potential source(s) during GS-3. This conclusion is further supported by distinctly different carbon contents in particles corresponding to GS-2.1 and GS-3. These results are consistent with previous estimates of proportional dust source contributions obtained using a mixing model based on Pb and Sr isotopic compositions in NEEM LGM ice and indicate millennial-scale changes in Greenland dust provenance that are probably linked to large-scale atmospheric circulation variabilities during the LGM.
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Affiliation(s)
- Seokhyun Ro
- Department of Ocean Sciences, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
- Division of Glacial Environment Research, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea
| | - Jonghyeon Park
- Department of Chemistry, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
- Marine Environment Research Department, Ara Consulting and Technology, 30 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea
| | - Hanjin Yoo
- Department of Chemistry, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
- Particle Pollution Research and Management Center, Inha University, 36 Gaetbeol-ro, Yeonsu-gu, Incheon, 21999, Republic of Korea
| | - Changhee Han
- Department of Water Environmental Safety Management, Korea Water Resources Corporation, 200 Sintanjin-ro, Daedeok-gu, Daejeon, 34350, Republic of Korea
| | - Ahhyung Lee
- Department of Ocean Sciences, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
- Unit of Frontier Exploration, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea
| | - Yoojin Lee
- Department of Chemistry, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
| | - Minjeong Kim
- Division of Glacial Environment Research, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea
- Department of Chemistry, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea
| | - Yeongcheol Han
- Division of Glacial Environment Research, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea
| | - Anders Svensson
- Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Julian 10 Maries Vej 30, 2100, Copenhagen, Denmark
| | - Jinhwa Shin
- Division of Glacial Environment Research, Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Republic of Korea
| | - Chul-Un Ro
- Department of Chemistry, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea.
- Particle Pollution Research and Management Center, Inha University, 36 Gaetbeol-ro, Yeonsu-gu, Incheon, 21999, Republic of Korea.
| | - Sungmin Hong
- Department of Ocean Sciences, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Republic of Korea.
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Moreno J, Ramos AM, Raposeiro PM, Santos RN, Rodrigues T, Naughton F, Moreno F, Trigo RM, Ibañez-Insa J, Ludwig P, Shi X, Hernández A. Identifying imprints of externally derived dust and halogens in the sedimentary record of an Iberian alpine lake for the past ∼13,500 years - Lake Peixão, Serra da Estrela (Central Portugal). THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 903:166179. [PMID: 37572895 DOI: 10.1016/j.scitotenv.2023.166179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 08/04/2023] [Accepted: 08/07/2023] [Indexed: 08/14/2023]
Abstract
Iberian lacustrine sediments are a valuable archive to document environmental changes since the last glacial termination, seen as key for anticipating future climate/environmental changes and their far-reaching implications for generations to come. Herein, multi-proxy-based indicators of a mountain lake record from Serra da Estrela were used to reconstruct atmospheric (in)fluxes and associated climatic/environmental changes over the last ∼13.5 ka. Depositions of long-range transported dust (likely from the Sahara) and halogens (primarily derived from seawater) were higher for the pre-Holocene, particularly in the late Bølling-Allerød-Younger Dryas period, compared to the Holocene. This synchronous increase could be related to a recognized dust-laden atmosphere, along with the combined effect of (i) an earlier proposed effective transport of Sahara dust for higher latitudes during cold periods and (ii) the progressive Polar Front expansion southwards, with the amplification of halogen activation reactions in lower latitudes due to greater closeness to snow/sea ice (halide-laden) surfaces. Additionally, the orographic blocking of Serra da Estrela may have played a critical role in increasing precipitation of Atlantic origin at higher altitudes, with the presence of snow prompting physical and chemical processes involving halogen species. In the Late Holocene, the dust proxy records highlighted two periods of enhanced input to Lake Peixão, the first (∼3.5-2.7 ka BP) after the end of the last African Humid Period and the second, from the 19th century onwards, agreeing with the advent of commercial agriculture, and human contribution to land degradation and dust emission in the Sahara/Sahel region. The oceanic imprints throughout the Holocene matched well with North Atlantic rapid climatic changes that, in turn, coincided with ice-rafted debris or Bond events and other records of increased storminess for the European coasts. Positive parallel peaks in halogens were found in recent times, probably connected to fire extinction by halogenated alkanes and roadway de-icing.
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Affiliation(s)
- J Moreno
- Universidade de Lisboa, Faculdade de Ciências, Instituto Dom Luiz, 1749-016 Lisboa, Portugal.
| | - A M Ramos
- Universidade de Lisboa, Faculdade de Ciências, Instituto Dom Luiz, 1749-016 Lisboa, Portugal; Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - P M Raposeiro
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Pólo dos Açores, Rua da Mãe de Deus, 9500-321 Ponta Delgada, Portugal; Faculdade de Ciências e Tecnologia, Universidade dos Açores, Rua da Mãe de Deus, 9500-321 Ponta Delgada, Portugal
| | - R N Santos
- Instituto Português do Mar e da Atmosfera (IPMA), Rua C do Aeroporto, 1749-077 Lisboa, Portugal
| | - T Rodrigues
- Instituto Português do Mar e da Atmosfera (IPMA), Rua C do Aeroporto, 1749-077 Lisboa, Portugal; Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Estrada da Penha, 8005-139 Faro, Portugal
| | - F Naughton
- Instituto Português do Mar e da Atmosfera (IPMA), Rua C do Aeroporto, 1749-077 Lisboa, Portugal; Centro de Ciências do Mar (CCMAR), Universidade do Algarve, Estrada da Penha, 8005-139 Faro, Portugal
| | - F Moreno
- Independent Researcher, Caminho da Portela, n. ° 97, Cascalha, 4940-061 Bico PCR, Portugal
| | - R M Trigo
- Universidade de Lisboa, Faculdade de Ciências, Instituto Dom Luiz, 1749-016 Lisboa, Portugal; Departamento de Meteorologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 21941-919, Brazil
| | - J Ibañez-Insa
- Geosciences Barcelona (GEO3BCN-CSIC), Lluís Solé i Sabarís s/n, E-08028 Barcelona, Spain
| | - P Ludwig
- Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - X Shi
- Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), China
| | - A Hernández
- Universidade da Coruña, GRICA Group, Centro Interdisciplinar de Química e Bioloxía (CICA), Rúa As Carballeiras, 15071 A Coruña, Spain
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3
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Sea ice fluctuations in the Baffin Bay and the Labrador Sea during glacial abrupt climate changes. Proc Natl Acad Sci U S A 2022; 119:e2203468119. [PMID: 36279448 PMCID: PMC9636944 DOI: 10.1073/pnas.2203468119] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sea ice decline in the North Atlantic and Nordic Seas has been proposed to contribute to the repeated abrupt atmospheric warmings recorded in Greenland ice cores during the last glacial period, known as Dansgaard-Oeschger (D-O) events. However, the understanding of how sea ice changes were coupled with abrupt climate changes during D-O events has remained incomplete due to a lack of suitable high-resolution sea ice proxy records from northwestern North Atlantic regions. Here, we present a subdecadal-scale bromine enrichment (Br
enr
) record from the NEEM ice core (Northwest Greenland) and sediment core biomarker records to reconstruct the variability of seasonal sea ice in the Baffin Bay and Labrador Sea over a suite of D-O events between 34 and 42 ka. Our results reveal repeated shifts between stable, multiyear sea ice (MYSI) conditions during cold stadials and unstable, seasonal sea ice conditions during warmer interstadials. The shift from stadial to interstadial sea ice conditions occurred rapidly and synchronously with the atmospheric warming over Greenland, while the amplitude of high-frequency sea ice fluctuations increased through interstadials. Our findings suggest that the rapid replacement of widespread MYSI with seasonal sea ice amplified the abrupt climate warming over the course of D-O events and highlight the role of feedbacks associated with late-interstadial seasonal sea ice expansion in driving the North Atlantic ocean–climate system back to stadial conditions.
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Újvári G, Klötzli U, Stevens T, Svensson A, Ludwig P, Vennemann T, Gier S, Horschinegg M, Palcsu L, Hippler D, Kovács J, Di Biagio C, Formenti P. Greenland Ice Core Record of Last Glacial Dust Sources and Atmospheric Circulation. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2022; 127:e2022JD036597. [PMID: 36245641 PMCID: PMC9542552 DOI: 10.1029/2022jd036597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 06/16/2023]
Abstract
Abrupt and large-scale climate changes have occurred repeatedly and within decades during the last glaciation. These events, where dramatic warming occurs over decades, are well represented in both Greenland ice core mineral dust and temperature records, suggesting a causal link. However, the feedbacks between atmospheric dust and climate change during these Dansgaard-Oeschger events are poorly known and the processes driving changes in atmospheric dust emission and transport remain elusive. Constraining dust provenance is key to resolving these gaps. Here, we present a multi-technique analysis of Greenland dust provenance using novel and established, source diagnostic isotopic tracers as well as results from a regional climate model including dust cycle simulations. We show that the existing dominant model for the provenance of Greenland dust as sourced from combined East Asian dust and Pacific volcanics is not supported. Rather, our clay mineralogical and Hf-Sr-Nd and D/H isotopic analyses from last glacial Greenland dust and an extensive range of Northern Hemisphere potential dust sources reveal three most likely scenarios (in order of probability): direct dust sourcing from the Taklimakan Desert in western China, direct sourcing from European glacial sources, or a mix of dust originating from Europe and North Africa. Furthermore, our regional climate modeling demonstrates the plausibility of European or mixed European/North African sources for the first time. We suggest that the origin of dust to Greenland is potentially more complex than previously recognized, demonstrating more uncertainty in our understanding dust climate feedbacks during abrupt events than previously understood.
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Affiliation(s)
- G. Újvári
- Centre for Astronomy and Earth SciencesInstitute for Geological and Geochemical ResearchEötvös Loránd Research NetworkBudapestHungary
- CSFKMTA Centre of ExcellenceBudapestHungary
- Department of Lithospheric ResearchUniversity of ViennaViennaAustria
| | - U. Klötzli
- Department of Lithospheric ResearchUniversity of ViennaViennaAustria
| | - T. Stevens
- Department of Earth SciencesUppsala UniversityUppsalaSweden
| | - A. Svensson
- Physics of Ice, Climate and EarthNiels Bohr InstituteUniversity of CopenhagenCopenhagenDenmark
| | - P. Ludwig
- Institute for Meteorology and Climate ResearchKarlsruhe Institute of TechnologyKarlsruheGermany
| | - T. Vennemann
- Institute of Earth Surface DynamicsUniversity of LausanneLausanneSwitzerland
| | - S. Gier
- Department of GeologyUniversity of ViennaViennaAustria
| | - M. Horschinegg
- Department of Lithospheric ResearchUniversity of ViennaViennaAustria
| | - L. Palcsu
- Isotope Climatology and Environmental Research CentreInstitute for Nuclear ResearchDebrecenHungary
| | - D. Hippler
- Institute of Applied GeosciencesGraz University of TechnologyGrazAustria
| | - J. Kovács
- Environmental Analytical and Geoanalytical Research GroupSzentágothai Research CentreUniversity of PécsPécsHungary
- Institute of Geography and Earth SciencesUniversity of PécsPécsHungary
| | - C. Di Biagio
- Université de Paris Cité and University Paris Est CreteilCNRSLISAParisFrance
| | - P. Formenti
- Université de Paris Cité and University Paris Est CreteilCNRSLISAParisFrance
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5
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Corella JP, Maffezzoli N, Spolaor A, Vallelonga P, Cuevas CA, Scoto F, Müller J, Vinther B, Kjær HA, Cozzi G, Edwards R, Barbante C, Saiz-Lopez A. Climate changes modulated the history of Arctic iodine during the Last Glacial Cycle. Nat Commun 2022; 13:88. [PMID: 35013214 PMCID: PMC8748508 DOI: 10.1038/s41467-021-27642-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 12/03/2021] [Indexed: 11/23/2022] Open
Abstract
Iodine has a significant impact on promoting the formation of new ultrafine aerosol particles and accelerating tropospheric ozone loss, thereby affecting radiative forcing and climate. Therefore, understanding the long-term natural evolution of iodine, and its coupling with climate variability, is key to adequately assess its effect on climate on centennial to millennial timescales. Here, using two Greenland ice cores (NEEM and RECAP), we report the Arctic iodine variability during the last 127,000 years. We find the highest and lowest iodine levels recorded during interglacial and glacial periods, respectively, modulated by ocean bioproductivity and sea ice dynamics. Our sub-decadal resolution measurements reveal that high frequency iodine emission variability occurred in pace with Dansgaard/Oeschger events, highlighting the rapid Arctic ocean-ice-atmosphere iodine exchange response to abrupt climate changes. Finally, we discuss if iodine levels during past warmer-than-present climate phases can serve as analogues of future scenarios under an expected ice-free Arctic Ocean. We argue that the combination of natural biogenic ocean iodine release (boosted by ongoing Arctic warming and sea ice retreat) and anthropogenic ozone-induced iodine emissions may lead to a near future scenario with the highest iodine levels of the last 127,000 years.
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Affiliation(s)
- Juan Pablo Corella
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Serrano 119, 28006, Madrid, Spain.
- CIEMAT, Environmental Department, Av. Complutense 40, 28040, Madrid, Spain.
| | - Niccolo Maffezzoli
- Physics of Ice Climate and Earth, Niels Bohr Institute, University of Copenhagen, Tagensvej 16, Copenhagen N, 2200, Denmark
- Institute of Polar Sciences, CNR- ISP, Via Torino 155, 30172, Venice, Italy
- Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172, Venice, Italy
| | - Andrea Spolaor
- Institute of Polar Sciences, CNR- ISP, Via Torino 155, 30172, Venice, Italy
- Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172, Venice, Italy
| | - Paul Vallelonga
- Physics of Ice Climate and Earth, Niels Bohr Institute, University of Copenhagen, Tagensvej 16, Copenhagen N, 2200, Denmark
| | - Carlos A Cuevas
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Serrano 119, 28006, Madrid, Spain
| | - Federico Scoto
- Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172, Venice, Italy
- Institute of Atmospheric Sciences and Climate, ISAC-CNR, S.P Lecce-Monteroni km1.2, 73100, Lecce, Italy
| | - Juliane Müller
- Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Am Alten Hafen 26, 27568, Bremerhaven, Germany
- MARUM Research Faculty, University of Bremen, Leobener Strasse 8, 28359, Bremen, Germany
| | - Bo Vinther
- Physics of Ice Climate and Earth, Niels Bohr Institute, University of Copenhagen, Tagensvej 16, Copenhagen N, 2200, Denmark
| | - Helle A Kjær
- Physics of Ice Climate and Earth, Niels Bohr Institute, University of Copenhagen, Tagensvej 16, Copenhagen N, 2200, Denmark
| | - Giulio Cozzi
- Institute of Polar Sciences, CNR- ISP, Via Torino 155, 30172, Venice, Italy
- Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172, Venice, Italy
| | - Ross Edwards
- Physics and Astronomy, Curtin University, Kent St, Bentley, WA, 6102, Australia
- Department of Civil and Environmental Engineering, UW-Madison, Madison, WI, 53706, USA
| | - Carlo Barbante
- Institute of Polar Sciences, CNR- ISP, Via Torino 155, 30172, Venice, Italy
- Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172, Venice, Italy
| | - Alfonso Saiz-Lopez
- Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Serrano 119, 28006, Madrid, Spain.
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6
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Abstract
Data availability and temporal resolution make it challenging to unravel the anatomy (duration and temporal phasing) of the Last Glacial abrupt climate changes. Here, we address these limitations by investigating the anatomy of abrupt changes using sub-decadal-scale records from Greenland ice cores. We highlight the absence of a systematic pattern in the anatomy of abrupt changes as recorded in different ice parameters. This diversity in the sequence of changes seen in ice-core data is also observed in climate parameters derived from numerical simulations which exhibit self-sustained abrupt variability arising from internal atmosphere-ice-ocean interactions. Our analysis of two ice cores shows that the diversity of abrupt warming transitions represents variability inherent to the climate system and not archive-specific noise. Our results hint that during these abrupt events, it may not be possible to infer statistically-robust leads and lags between the different components of the climate system because of their tight coupling.
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7
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Spolaor A, Varin C, Pedeli X, Christille JM, Kirchgeorg T, Giardi F, Cappelletti D, Turetta C, Cairns WRL, Gambaro A, Bernagozzi A, Gallet JC, Björkman MP, Barbaro E. Source, timing and dynamics of ionic species mobility in the Svalbard annual snowpack. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 751:141640. [PMID: 32892077 DOI: 10.1016/j.scitotenv.2020.141640] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/29/2020] [Accepted: 08/09/2020] [Indexed: 06/11/2023]
Abstract
Nearly all ice core archives from the Arctic and middle latitudes (such as the Alps), apart from some very high elevation sites in Greenland and the North Pacific, are strongly influenced by melting processes. The increases in the average Arctic temperature has enhanced surface snow melting even of higher elevation ice caps, especially on the Svalbard Archipelago. The increase of the frequency and altitude of winter "rain on snow" events as well as the increase of the length of the melting season have had a direct impact on the chemical composition of the seasonal and permanent snow layers due to different migration processes of water-soluble species, such as inorganic ions. This re-allocation along the snowpack of ionic species could significantly modify the original chemical signal present in the annual snow. This paper aims to give a picture of the evolution of the seasonal snow strata with a daily time resolution to better understand: a) the processes that can influence deposition b) the distribution of ions in annual snow c) the impact of the presence of liquid water on chemical re-distribution within the annual snow pack. Specifically, the chemical composition of the first 100 cm of seasonal snow on the Austre Brøggerbreen Glacier (Spitsbergen, Svalbard Islands, Norway) was monitored daily from the 27th of March to the 31st of May 2015. The experimental period covered almost the entire Arctic spring until the melting season. This unique dataset gives us a daily picture of the snow pack composition, and helps us to understand the behaviour of cations (K+, Ca2+, Na+, Mg2+) and anions (Br-, I-, SO42-, NO3-, Cl-, MSA) in the Svalbard snow pack. We demonstrate that biologically related depositions occur only at the end of the snow season and that rain and melting events have different impacts on the snowpack chemistry.
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Affiliation(s)
- Andrea Spolaor
- Institute of Polar Sciences, ISP-CNR, Via Torino 155, 30172 Venice-Mestre, Italy; Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172 Venice-Mestre, Italy.
| | - Cristiano Varin
- Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172 Venice-Mestre, Italy
| | - Xanthi Pedeli
- Athens University of Economics and Business, Department of Statistics, 76 Patision Street, 10434 Athens, Greece
| | - Jean Marc Christille
- Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA), Loc. Lignan 39, 11020 Nus, AO, Italy; Dipartimento di Fisica e Geologia, Università degli Studi di Perugia, I-06123 Perugia, Italy
| | - Torben Kirchgeorg
- Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172 Venice-Mestre, Italy
| | - Fabio Giardi
- Department of Physics and Astronomy, University of Florence, Via Giovanni Sansone, 1, I-50019 Sesto Fiorentino, Florence, Italy
| | - David Cappelletti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, I-06123 Perugia, Italy
| | - Clara Turetta
- Institute of Polar Sciences, ISP-CNR, Via Torino 155, 30172 Venice-Mestre, Italy; Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172 Venice-Mestre, Italy
| | - Warren R L Cairns
- Institute of Polar Sciences, ISP-CNR, Via Torino 155, 30172 Venice-Mestre, Italy; Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172 Venice-Mestre, Italy
| | - Andrea Gambaro
- Institute of Polar Sciences, ISP-CNR, Via Torino 155, 30172 Venice-Mestre, Italy; Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172 Venice-Mestre, Italy
| | - Andrea Bernagozzi
- Astronomical Observatory of the Autonomous Region of the Aosta Valley (OAVdA), Loc. Lignan 39, 11020 Nus, AO, Italy
| | | | - Mats P Björkman
- University of Gothenburg, Department of Earth Sciences, Box 460, 40530 Göteborg, Sweden
| | - Elena Barbaro
- Institute of Polar Sciences, ISP-CNR, Via Torino 155, 30172 Venice-Mestre, Italy; Ca' Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30172 Venice-Mestre, Italy
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8
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Sherwood SC, Webb MJ, Annan JD, Armour KC, Forster PM, Hargreaves JC, Hegerl G, Klein SA, Marvel KD, Rohling EJ, Watanabe M, Andrews T, Braconnot P, Bretherton CS, Foster GL, Hausfather Z, von der Heydt AS, Knutti R, Mauritsen T, Norris JR, Proistosescu C, Rugenstein M, Schmidt GA, Tokarska KB, Zelinka MD. An Assessment of Earth's Climate Sensitivity Using Multiple Lines of Evidence. REVIEWS OF GEOPHYSICS (WASHINGTON, D.C. : 1985) 2020; 58:e2019RG000678. [PMID: 33015673 PMCID: PMC7524012 DOI: 10.1029/2019rg000678] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 04/22/2020] [Accepted: 06/24/2020] [Indexed: 05/10/2023]
Abstract
We assess evidence relevant to Earth's equilibrium climate sensitivity per doubling of atmospheric CO2, characterized by an effective sensitivity S. This evidence includes feedback process understanding, the historical climate record, and the paleoclimate record. An S value lower than 2 K is difficult to reconcile with any of the three lines of evidence. The amount of cooling during the Last Glacial Maximum provides strong evidence against values of S greater than 4.5 K. Other lines of evidence in combination also show that this is relatively unlikely. We use a Bayesian approach to produce a probability density function (PDF) for S given all the evidence, including tests of robustness to difficult-to-quantify uncertainties and different priors. The 66% range is 2.6-3.9 K for our Baseline calculation and remains within 2.3-4.5 K under the robustness tests; corresponding 5-95% ranges are 2.3-4.7 K, bounded by 2.0-5.7 K (although such high-confidence ranges should be regarded more cautiously). This indicates a stronger constraint on S than reported in past assessments, by lifting the low end of the range. This narrowing occurs because the three lines of evidence agree and are judged to be largely independent and because of greater confidence in understanding feedback processes and in combining evidence. We identify promising avenues for further narrowing the range in S, in particular using comprehensive models and process understanding to address limitations in the traditional forcing-feedback paradigm for interpreting past changes.
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Affiliation(s)
- S C Sherwood
- Climate Change Research Centre and ARC Centre of Excellence for Climate Extremes University of New South Wales Sydney Sydney New South Wales Australia
| | - M J Webb
- Met Office Hadley Centre Exeter UK
| | | | | | - P M Forster
- Priestley International Centre for Climate University of Leeds Leeds UK
| | | | - G Hegerl
- School of Geosciences University of Edinburgh Edinburgh UK
| | | | - K D Marvel
- Department of Applied Physics and Applied Math Columbia University New York NY USA
- NASA Goddard Institute for Space Studies New York NY USA
| | - E J Rohling
- Research School of Earth Sciences Australian National University Canberra ACT Australia
- Ocean and Earth Science, National Oceanography Centre University of Southampton Southampton UK
| | - M Watanabe
- Atmosphere and Ocean Research Institute The University of Tokyo Tokyo Japan
| | | | - P Braconnot
- Laboratoire des Sciences du Climat et de l'Environnement, unité mixte CEA-CNRS-UVSQ Université Paris-Saclay Gif sur Yvette France
| | | | - G L Foster
- Ocean and Earth Science, National Oceanography Centre University of Southampton Southampton UK
| | | | - A S von der Heydt
- Institute for Marine and Atmospheric Research, and Centre for Complex Systems Science Utrecht University Utrecht The Netherlands
| | - R Knutti
- Institute for Atmospheric and Climate Science Zurich Switzerland
| | - T Mauritsen
- Department of Meteorology Stockholm University Stockholm Sweden
| | - J R Norris
- Scripps Institution of Oceanography La Jolla CA USA
| | - C Proistosescu
- Department of Atmospheric Sciences and Department of Geology University of Illinois at Urbana-Champaign Urbana IL USA
| | - M Rugenstein
- Max Planck Institute for Meteorology Hamburg Germany
| | - G A Schmidt
- NASA Goddard Institute for Space Studies New York NY USA
| | - K B Tokarska
- School of Geosciences University of Edinburgh Edinburgh UK
- Institute for Atmospheric and Climate Science Zurich Switzerland
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9
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Tierney JE, Poulsen CJ, Montañez IP, Bhattacharya T, Feng R, Ford HL, Hönisch B, Inglis GN, Petersen SV, Sagoo N, Tabor CR, Thirumalai K, Zhu J, Burls NJ, Foster GL, Goddéris Y, Huber BT, Ivany LC, Kirtland Turner S, Lunt DJ, McElwain JC, Mills BJW, Otto-Bliesner BL, Ridgwell A, Zhang YG. Past climates inform our future. Science 2020; 370:370/6517/eaay3701. [DOI: 10.1126/science.aay3701] [Citation(s) in RCA: 111] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
| | - Christopher J. Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Isabel P. Montañez
- Department of Earth and Planetary Sciences, University of California, Davis, Davis, CA, USA
| | - Tripti Bhattacharya
- Department of Earth and Environmental Sciences, Syracuse University, Syracuse, NY, USA
| | - Ran Feng
- Department of Geosciences, University of Connecticut, Storrs, CT, USA
| | - Heather L. Ford
- School of Geography, Queen Mary University of London, London, UK
| | - Bärbel Hönisch
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | - Gordon N. Inglis
- Department of Earth and Environmental Sciences, Columbia University, Palisades, NY, USA
| | - Sierra V. Petersen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Navjit Sagoo
- Department of Meteorology, University of Stockholm, Stockholm, Sweden
| | - Clay R. Tabor
- Department of Geosciences, University of Connecticut, Storrs, CT, USA
| | | | - Jiang Zhu
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Natalie J. Burls
- Department of Atmospheric, Oceanic, and Earth Sciences, George Mason University, Fairfax, VA, USA
| | - Gavin L. Foster
- Department of Earth and Environmental Sciences, Columbia University, Palisades, NY, USA
| | - Yves Goddéris
- Centre National de la Recherche Scientifique, Géosciences Environnement Toulouse, Toulouse, France
| | - Brian T. Huber
- Department of Paleobiology, Smithsonian National Museum of Natural History, Washington, DC, USA
| | - Linda C. Ivany
- Department of Earth and Environmental Sciences, Syracuse University, Syracuse, NY, USA
| | | | - Daniel J. Lunt
- School of Geographical Sciences, University of Bristol, Bristol, UK
| | | | | | | | - Andy Ridgwell
- Department of Earth Science, University of California, Riverside, Riverside, CA, USA
| | - Yi Ge Zhang
- Department of Oceanography, Texas A&M University, College Station, TX, USA
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10
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Martinez-Swatson K, Mihály E, Lange C, Ernst M, Dela Cruz M, Price MJ, Mikkelsen TN, Christensen JH, Lundholm N, Rønsted N. Biomonitoring of Polycyclic Aromatic Hydrocarbon Deposition in Greenland Using Historical Moss Herbarium Specimens Shows a Decrease in Pollution During the 20 th Century. FRONTIERS IN PLANT SCIENCE 2020; 11:1085. [PMID: 32760420 PMCID: PMC7373755 DOI: 10.3389/fpls.2020.01085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
Although most point sources of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbons (PAHs), are at lower latitudes, the Arctic region is contaminated. In particular, PAHs now dominate the POP body burden of the region's marine biota at the lower trophic levels. Greenlandic Inuits have the most elevated levels of POPs in their blood compared to any other population, due to their consumption of seal meat and other marine mammals. PAHs, the by-products of the incomplete combustion of petroleum products, are known carcinogens and have been shown to affect the immune system, reproduction, endocrine functions, and the nervous system. With industrial activities and climate change set to increase local PAH emissions, it is paramount to document changes in atmospheric PAH deposition to further investigate PAH exposure in the region and attribute contaminations to their sources. As a measure of atmospheric pollution, we sampled bryophyte herbarium specimens of three common and widespread species collected in Greenland between the 1920s and 1970s after which time new collections were not available. They were analyzed for 19 PAHs using GC-MS (gas chromatography mass spectrometry). The presence of more low-molecular-weight PAHs than high-molecular-weight PAHs is evidence that the PAH contamination in Greenland is due to long-range transport rather than originating from local sources. The results show peaks in PAH atmospheric deposition in the first part of the 19th century followed by a trend of decrease, which mirror global trends in atmospheric pollution known from those periods. PAHs associated with wood and fossil-fuel combustion decrease in the 1970s coinciding with the disappearance of charcoal pits and foundries in Europe and North America, and a shift away from domestic heating with wood during the 19th century. The results highlight the value of bryophytes as bioindicators to measure PAH atmospheric pollution as well as the unrealized potential of herbaria as historical records of environmental change.
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Affiliation(s)
- Karen Martinez-Swatson
- Natural History Museum of Denmark, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Eszter Mihály
- Natural History Museum of Denmark, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Christian Lange
- Natural History Museum of Denmark, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Madeleine Ernst
- Natural History Museum of Denmark, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Center for Newborn Screening, Department of Congenital Disorders, Statens Serum Institute, Copenhagen, Denmark
| | - Majbrit Dela Cruz
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Michelle J. Price
- Conservatoire et Jardin Botaniques de la Ville de Genève, Geneva, Switzerland
| | | | - Jan H. Christensen
- Department of Plant and Environmental Sciences, Faculty of Science, University of Copenhagen, Frederiksberg, Denmark
| | - Nina Lundholm
- Natural History Museum of Denmark, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Nina Rønsted
- Natural History Museum of Denmark, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
- Science and Conservation, National Tropical Botanical Garden, Kalaheo, HI, United States
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11
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Xiao C, Du Z, Handley MJ, Mayewski PA, Cao J, Schüpbach S, Zhang T, Petit JR, Li C, Han Y, Li Y, Ren J. Iron in the NEEM ice core relative to Asian loess records over the last glacial-interglacial cycle. Natl Sci Rev 2020; 8:nwaa144. [PMID: 34691679 PMCID: PMC8310736 DOI: 10.1093/nsr/nwaa144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 06/16/2020] [Accepted: 06/23/2020] [Indexed: 11/13/2022] Open
Abstract
Mineral dust can indirectly affect the climate by supplying bioavailable iron (Fe) to the ocean. Here, we present the records of dissolved Fe (DFe) and total Fe (TDFe) in North Greenland Eemian Ice Drilling (NEEM) ice core over the past 110 kyr BP. The Fe records are significantly negatively correlated with the carbon-dioxide (CO2) concentrations during cold periods. The results suggest that the changes in Fe fluxes over the past 110 kyr BP in the NEEM ice core are consistent with those in Chinese loess records because the mineral-dust distribution is controlled by the East Asian deserts. Furthermore, the variations in the dust input on a global scale are most likely driven by changes in solar radiation during the last glacial-interglacial cycle in response to Earth's orbital cycles. In the last glacial-interglacial cycle, the DFe/TDFe ratios were higher during the warm periods (following the post-Industrial Revolution and during the Holocene and last interglacial period) than during the main cold period (i.e. the last glacial maximum (LGM)), indicating that the aeolian input of iron and the iron fertilization effect on the oceans have a non-linear relationship during different periods. Although the burning of biomass aerosols has released large amounts of DFe since the Industrial Revolution, no significant responses are observed in the DFe and TDFe variations during this period, indicating that severe anthropogenic contamination has no significant effect on the DFe (TDFe) release in the NEEM ice core.
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Affiliation(s)
- Cunde Xiao
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China
| | - Zhiheng Du
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Mike J Handley
- Climate Change Institute, School of Earth and Climate Sciences, University of Maine, Orono, ME 04469, USA
| | - Paul A Mayewski
- Climate Change Institute, School of Earth and Climate Sciences, University of Maine, Orono, ME 04469, USA
| | - Junji Cao
- Key Laboratory of Aerosol Science and Technology, SKLLQG, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710061, China
| | - Simon Schüpbach
- Climate and Environmental Physics, Physics Institute, University of Bern, Bern 3012, Switzerland
| | - Tong Zhang
- Institute of Tibetan Plateau and Polar Meteorology, Chinese Academy of Meteorological Sciences, Beijing 100081, China
| | - Jean-Robert Petit
- Institut des Geosciences de I'Environment (IGE), University Grenoble Alpes, Grenoble F38000, France
| | - Chuanjin Li
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | | | - Yuefang Li
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Jiawen Ren
- State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
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12
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Erhardt T, Jensen CM, Borovinskaya O, Fischer H. Single Particle Characterization and Total Elemental Concentration Measurements in Polar Ice Using Continuous Flow Analysis-Inductively Coupled Plasma Time-of-Flight Mass Spectrometry. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:13275-13283. [PMID: 31608632 DOI: 10.1021/acs.est.9b03886] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Continuous flow analysis (CFA) has become widely used for the measurement of aerosol-derived impurities in ice-core samples, resulting in high-resolution data sets of past aerosol deposition. Here, we present first results from coupling an inductively coupled plasma time-of-flight mass spectrometer (TOFMS) to a traditional CFA system. This setup enables the measurement of exactly coregistered elemental concentrations over the full mass range without degradation of sensitivity with an increasing number of analytes. The resulting total elemental concentration records have similar or better resolution than the established spectrophotometric methods. The unique capability of a TOFMS to measure fast transient signals and to still cover the full mass range furthermore enables the detection of the ionization of individual insoluble particles entering the plasma. The resulting mass spectra of the particles can be used to investigate the relative elemental composition of the mineral dust particles preserved in ice. The presented analysis of iron-bearing particles indicates that most of the particulate iron in Greenland ice is associated with Mg and Al and is likely part of clay minerals such as illite.
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Affiliation(s)
- Tobias Erhardt
- Climate and Environmental Physics and Oeschger Center for Climate Change Research , University of Bern , Sidlerstrasse 5 , 3012 Bern , Switzerland
| | - Camilla M Jensen
- Climate and Environmental Physics and Oeschger Center for Climate Change Research , University of Bern , Sidlerstrasse 5 , 3012 Bern , Switzerland
| | | | - Hubertus Fischer
- Climate and Environmental Physics and Oeschger Center for Climate Change Research , University of Bern , Sidlerstrasse 5 , 3012 Bern , Switzerland
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13
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East Greenland ice core dust record reveals timing of Greenland ice sheet advance and retreat. Nat Commun 2019; 10:4494. [PMID: 31582753 PMCID: PMC6776541 DOI: 10.1038/s41467-019-12546-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 09/18/2019] [Indexed: 12/04/2022] Open
Abstract
Accurate estimates of the past extent of the Greenland ice sheet provide critical constraints for ice sheet models used to determine Greenland’s response to climate forcing and contribution to global sea level. Here we use a continuous ice core dust record from the Renland ice cap on the east coast of Greenland to constrain the timing of changes to the ice sheet margin and relative sea level over the last glacial cycle. During the Holocene and the previous interglacial period (Eemian) the dust record was dominated by coarse particles consistent with rock samples from central East Greenland. From the coarse particle concentration record we infer the East Greenland ice sheet margin advanced from 113.4 ± 0.4 to 111.0 ± 0.4 ka BP during the glacial onset and retreated from 12.1 ± 0.1 to 9.0 ± 0.1 ka BP during the last deglaciation. These findings constrain the possible response of the Greenland ice sheet to climate forcings. Accurate measurements of the past extent of the Greenland ice sheet are crucial to understand its response to changing climate conditions. Here, the authors present a dust record from an ice core from the east coast of Greenland to provide detailed time constraints on ice sheet advance and retreat over the last interglacials.
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14
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Du Z, Xiao C, Handley MJ, Mayewski PA, Li C, Liu S, Ma X, Yang J. Fe variation characteristics and sources in snow samples along a traverse from Zhongshan Station to Dome A, East Antarctica. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 675:380-389. [PMID: 31030144 DOI: 10.1016/j.scitotenv.2019.04.139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Revised: 04/07/2019] [Accepted: 04/09/2019] [Indexed: 06/09/2023]
Abstract
Iron concentrations in the Southern Ocean are thought to act as a driver of the regular glacial-interglacial cycles in atmospheric carbon dioxide (CO2). This study presents the concentrations of bioavailable Fe (dissolved Fe (DFe) and total dissolved Fe (TDFe)), major ions (Na+, K+, Mg2+, Ca2+, Cl-,NO3-,SO42- and methanesulfonic acid (MSA)), heavy metal elements (Sr, Pb, V, Ti and Cd), and rare earth elements (REEs; specifically, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and the oxygen and hydrogen isotopic compositions (δ18O and δD) from a series of surface snow samples collected during from January 22 to February 5, 2017 along a traverse from Zhongshan Station to Dome A in East Antarctica. The results reflect the Antarctic surface snow Fe and the other trace element concentrations on the East Antarctica ice sheet. In particular, the DFe and TDFe concentrations were measured using inductively coupled plasma sector field mass spectrometry (SF-ICP-MS). The concentration patterns of DFe and TDFe show three different stages along this transect. First, there is an abrupt decrease with distance inland from the coast and then a slight decreasing trend with increasing elevation. The maximum concentrations were observed at distances of 450-600 km from the coast, indicating that there are different potential sources and/or transporting air masses. The variations show that the sources and processes that deliver bioavailable Fe differ along this transect. These data are useful for assessing bioavailable Fe release from the Antarctic ice sheet.
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Affiliation(s)
- Zhiheng Du
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Cunde Xiao
- State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China.
| | - Mike J Handley
- Climate Change Institute, University of Maine, Orono, ME 04469, USA
| | - Paul A Mayewski
- Climate Change Institute, University of Maine, Orono, ME 04469, USA
| | - Chuanjin Li
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Shiwei Liu
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Xiangyu Ma
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Jiao Yang
- State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
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15
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Impact of abrupt sea ice loss on Greenland water isotopes during the last glacial period. Proc Natl Acad Sci U S A 2019; 116:4099-4104. [PMID: 30760586 PMCID: PMC6410777 DOI: 10.1073/pnas.1807261116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Dansgaard–Oeschger events contained in Greenland ice cores constitute the archetypal record of abrupt climate change. An accurate understanding of these events hinges on interpretation of Greenland records of oxygen and nitrogen isotopes. We present here the important results from a suite of modeled Dansgaard–Oeschger events. These simulations show that the change in oxygen isotope per degree of warming becomes smaller during larger events. Abrupt reductions in sea ice also emerge as a strong control on ice core oxygen isotopes because of the influence on both the moisture source and the regional temperature increase. This work confirms the significance of sea ice for past abrupt warming events. Greenland ice cores provide excellent evidence of past abrupt climate changes. However, there is no universally accepted theory of how and why these Dansgaard–Oeschger (DO) events occur. Several mechanisms have been proposed to explain DO events, including sea ice, ice shelf buildup, ice sheets, atmospheric circulation, and meltwater changes. DO event temperature reconstructions depend on the stable water isotope (δ18O) and nitrogen isotope measurements from Greenland ice cores: interpretation of these measurements holds the key to understanding the nature of DO events. Here, we demonstrate the primary importance of sea ice as a control on Greenland ice core δ18O: 95% of the variability in δ18O in southern Greenland is explained by DO event sea ice changes. Our suite of DO events, simulated using a general circulation model, accurately captures the amplitude of δ18O enrichment during the abrupt DO event onsets. Simulated geographical variability is broadly consistent with available ice core evidence. We find an hitherto unknown sensitivity of the δ18O paleothermometer to the magnitude of DO event temperature increase: the change in δ18O per Kelvin temperature increase reduces with DO event amplitude. We show that this effect is controlled by precipitation seasonality.
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16
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Han C, Do Hur S, Han Y, Lee K, Hong S, Erhardt T, Fischer H, Svensson AM, Steffensen JP, Vallelonga P. High-resolution isotopic evidence for a potential Saharan provenance of Greenland glacial dust. Sci Rep 2018; 8:15582. [PMID: 30348975 PMCID: PMC6197225 DOI: 10.1038/s41598-018-33859-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 10/07/2018] [Indexed: 11/09/2022] Open
Abstract
Dust concentrations in Greenland ice show pronounced glacial/interglacial variations with almost two orders of magnitude increase during the Last Glacial Maximum. Greenland glacial dust was previously sourced to two East Asian deserts: the Taklimakan and Gobi deserts. Here we report the first high-resolution Pb and Sr isotopic evidence for a significant Saharan dust influence in Greenland during the last glacial period, back to ~31 kyr ago, from the Greenland NEEM ice core. We find that during Greenland Stadials 3-5.1 (~31 to 23 kyr ago), the primary dust provenance was East Asia, as previously proposed. Subsequently, the Saharan isotopic signals emerge during Greenland Stadials 2.1a-2.1c (~22.6 to 14.7 kyr ago) and from the late Bølling-Allerød to the Younger Dryas periods (~13.6 to 12 kyr ago), coincident with increased aridity in the Sahara and efficient northward transport of dust during these cold periods. A mixing isotopic model proposes the Sahara as an important source, accounting for contribution to Greenland glacial dust of up to 50%, particularly during Greenland Stadial 2.1b and the late Bølling-Allerød to the Younger Dryas periods. Our findings provide new insights into climate-related dust provenance changes and essential paleoclimatic constraints on dust-climate feedbacks in northern high latitudes.
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Affiliation(s)
- Changhee Han
- Department of Ocean Sciences, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Korea
- Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Korea
| | - Soon Do Hur
- Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Korea
| | - Yeongcheol Han
- Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Korea
| | - Khanghyun Lee
- Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon, 21990, Korea
| | - Sungmin Hong
- Department of Ocean Sciences, Inha University, 100 Inha-ro, Michuhol-gu, Incheon, 22212, Korea.
| | - Tobias Erhardt
- Climate and Environmental Physics, Physics Institute & Oeschger Center for Climate Change Research, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland
| | - Hubertus Fischer
- Climate and Environmental Physics, Physics Institute & Oeschger Center for Climate Change Research, University of Bern, Sidlerstrasse 5, 3012, Bern, Switzerland
| | - Anders M Svensson
- Center for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Julian Maries Vej 30, 2100, Copenhagen, Denmark
| | - Jørgen Peder Steffensen
- Center for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Julian Maries Vej 30, 2100, Copenhagen, Denmark
| | - Paul Vallelonga
- Center for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Julian Maries Vej 30, 2100, Copenhagen, Denmark
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