1
|
Barkley AE, Winckler G, Recasens C, Kaplan MR, Koffman BG, Calabozo F, Middleton JL, Anderson RF, Cai Y, Bolge L, Longman J, Goldstein SL. Patagonian dust, Agulhas Current, and Antarctic ice-rafted debris contributions to the South Atlantic Ocean over the past 150,000 years. Proc Natl Acad Sci U S A 2024; 121:e2402120121. [PMID: 39042680 PMCID: PMC11295081 DOI: 10.1073/pnas.2402120121] [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: 01/30/2024] [Accepted: 06/12/2024] [Indexed: 07/25/2024] Open
Abstract
Disentangling inputs of aeolian dust, ice-rafted debris (IRD), and eroded continental detritus delivered by ocean currents to marine sediments provide important insights into Earth System processes and climate. This study uses Sr-Nd-Pb isotope ratios of the continent-derived (lithogenic) fraction in deep-sea core TN057-6 from the subantarctic Southern Ocean southwest of Africa over the past 150,000 y to identify source regions and quantify their relative contributions and fluxes utilizing a mixing model set in a Bayesian framework. The data are compared with proxies from parallel core Ocean Drilling Program Site 1090 and newly presented data from potential South America aeolian dust source areas (PSAs), allowing for an integrated investigation into atmospheric, oceanic, and cryospheric dynamics. PSA inputs varied on glacial/interglacial timescales, with southern South American sources dominating up to 88% of the lithogenic fraction (mainly Patagonia, which provided up to 68%) during cold periods, while southern African sources were more important during interglacials. During the warmer Marine Isotope Stage (MIS) 3 of the last glacial period, lithogenic fluxes were twice that of colder MIS2 and MIS4 at times, and showed unique isotope ratios best explained by Antarctic-derived IRD, likely from the Weddell Sea. The IRD intrusions contributed up to 41% at times and followed Antarctic millennial warming events that raised temperatures, causing instability of icesheet margins. High IRD was synchronous with increased bioavailable iron, nutrient utilization, high biological productivity, and decreased atmospheric CO2. Overall, TN057-6 sediments record systematic Southern Hemisphere climate shifts and cryospheric changes that impacted biogeochemical cycling on both glacial/interglacial and subglacial timescales.
Collapse
Affiliation(s)
- Anne E. Barkley
- Division of Geochemistry, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY10964
| | - Gisela Winckler
- Division of Geochemistry, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY10964
- Department of Earth and Environmental Sciences, Columbia University, New York, NY10027
| | - Cristina Recasens
- Division of Geochemistry, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY10964
| | - Michael R. Kaplan
- Division of Geochemistry, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY10964
| | | | - Fernando Calabozo
- Centro de Investigaciones en Ciencias de la Tierra, Ciudad Universitaria, CórdobaX5016CGA, Argentina
| | - Jennifer L. Middleton
- Division of Geochemistry, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY10964
| | - Robert F. Anderson
- Division of Geochemistry, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY10964
- Department of Earth and Environmental Sciences, Columbia University, New York, NY10027
| | - Yue Cai
- Nanjing Institute of Geology and Palaeontology and Center for Excellence in Life and Paleoenvironment, Chinese Academy of Sciences, Nanjing210008, China
| | - Louise Bolge
- Division of Geochemistry, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY10964
| | - Jack Longman
- Marine Isotope Geochemistry, Institute for Chemistry and Biology of the Marine Environment, Carl von Ossietzky Universität Oldenburg, Oldenburg26129, Germany
- Department of Geography and Environmental Sciences, Northumbria University, Newcastle-upon-TyneNE1 8ST, United Kingdom
| | - Steven L. Goldstein
- Division of Geochemistry, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY10964
- Department of Earth and Environmental Sciences, Columbia University, New York, NY10027
| |
Collapse
|
2
|
Weis J, Chase Z, Schallenberg C, Strutton PG, Bowie AR, Fiddes SL. One-third of Southern Ocean productivity is supported by dust deposition. Nature 2024; 629:603-608. [PMID: 38750234 DOI: 10.1038/s41586-024-07366-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 03/28/2024] [Indexed: 05/18/2024]
Abstract
Natural iron fertilization of the Southern Ocean by windblown dust has been suggested to enhance biological productivity and modulate the climate1-3. Yet, this process has never been quantified across the Southern Ocean and at annual timescales4,5. Here we combined 11 years of nitrate observations from autonomous biogeochemical ocean profiling floats with a Southern Hemisphere dust simulation to empirically derive the relationship between dust-iron deposition and annual net community production (ANCP) in the iron-limited Southern Ocean. Using this relationship, we determined the biological response to dust-iron in the pelagic perennially ice-free Southern Ocean at present and during the last glacial maximum (LGM). We estimate that dust-iron now supports 33% ± 15% of Southern Ocean ANCP. During the LGM, when dust deposition was 5-40-fold higher than today, the contribution of dust to Southern Ocean ANCP was much greater, estimated at 64% ± 13%. We provide quantitative evidence of basin-wide dust-iron fertilization of the Southern Ocean and the potential magnitude of its impact on glacial-interglacial timescales, supporting the idea of the important role of dust in the global carbon cycle and climate6-8.
Collapse
Affiliation(s)
- Jakob Weis
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, Tasmania, Australia.
- Australian Research Council Centre of Excellence for Climate Extremes (CLEX), University of Tasmania, Hobart, Tasmania, Australia.
| | - Zanna Chase
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, Tasmania, Australia
- Australian Research Council Centre for Excellence in Antarctic Science (ACEAS), University of Tasmania, Hobart, Tasmania, Australia
| | - Christina Schallenberg
- Australian Antarctic Program Partnership (AAPP), University of Tasmania, Hobart, Tasmania, Australia
- Environment, CSIRO, Hobart, Tasmania, Australia
| | - Peter G Strutton
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, Tasmania, Australia
- Australian Research Council Centre of Excellence for Climate Extremes (CLEX), University of Tasmania, Hobart, Tasmania, Australia
- Australian Research Council Centre for Excellence in Antarctic Science (ACEAS), University of Tasmania, Hobart, Tasmania, Australia
| | - Andrew R Bowie
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, Tasmania, Australia
- Australian Antarctic Program Partnership (AAPP), University of Tasmania, Hobart, Tasmania, Australia
| | - Sonya L Fiddes
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, Tasmania, Australia
- Australian Research Council Centre of Excellence for Climate Extremes (CLEX), University of Tasmania, Hobart, Tasmania, Australia
- Australian Antarctic Program Partnership (AAPP), University of Tasmania, Hobart, Tasmania, Australia
| |
Collapse
|
3
|
Stubbins B, Leier AL, Barbeau DL, Pullen A, Abell JT, Nie J, Zárate MA, Fidler MK. Global climate forcing on late Miocene establishment of the Pampean aeolian system in South America. Nat Commun 2023; 14:6899. [PMID: 37899425 PMCID: PMC10613622 DOI: 10.1038/s41467-023-42537-3] [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: 06/08/2023] [Accepted: 10/12/2023] [Indexed: 10/31/2023] Open
Abstract
Wind-blown dust from southern South America links the terrestrial, marine, atmospheric, and biological components of Earth's climate system. The Pampas of central Argentina (~33°-39° S) contain a Miocene to Holocene aeolian record that spans an important interval of global cooling. Upper Miocene sediment provenance based on n = 3299 detrital-zircon U-Pb ages is consistent with the provenance of Pleistocene-Holocene deposits, indicating the Pampas are the site of a long-lived fluvial-aeolian system that has been operating since the late Miocene. Here, we show the establishment of aeolian sedimentation in the Pampas coincided with late Miocene cooling. These findings, combined with those from the Chinese Loess Plateau (~33°-39° N) underscore: (1) the role of fluvial transport in the development and maintenance of temporally persistent mid-latitude loess provinces; and (2) a global-climate forcing mechanism behind the establishment of large mid-latitude loess provinces during the late Miocene.
Collapse
Affiliation(s)
- Blake Stubbins
- School of the Earth, Ocean and Environment, University of South Carolina, Columbia, SC, 29208, USA
| | - Andrew L Leier
- School of the Earth, Ocean and Environment, University of South Carolina, Columbia, SC, 29208, USA
| | - David L Barbeau
- School of the Earth, Ocean and Environment, University of South Carolina, Columbia, SC, 29208, USA
| | - Alex Pullen
- Department of Environmental Engineering and Earth Sciences, Clemson University, Clemson, SC, 29634, USA.
| | - Jordan T Abell
- Department of Geosciences, University of Arizona, Tucson, AZ, 85721, USA
- Department of Earth and Environmental Sciences, Lehigh University, Pennsylvania, PA, 18015, USA
| | - Junsheng Nie
- Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, China
| | - Marcelo A Zárate
- Instituto de Ciencias de la Tierra y Ambientales de La Pampa, CONICET Universidad Nacional de La Pampa, La Pampa, Argentina
| | - Mary Kate Fidler
- Department of Environmental Engineering and Earth Sciences, Clemson University, Clemson, SC, 29634, USA
| |
Collapse
|
4
|
Nghiem AA, Prommer H, Mozumder MRH, Siade A, Jamieson J, Ahmed KM, van Geen A, Bostick BC. Sulfate reduction accelerates groundwater arsenic contamination even in aquifers with abundant iron oxides. NATURE WATER 2023; 1:151-165. [PMID: 37034542 PMCID: PMC10074394 DOI: 10.1038/s44221-022-00022-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 12/19/2022] [Indexed: 02/18/2023]
Abstract
Groundwater contamination by geogenic arsenic is a global problem affecting nearly 200 million people. In South and Southeast Asia, a cost-effective mitigation strategy is to use oxidized low-arsenic aquifers rather than reduced high-arsenic aquifers. Aquifers with abundant oxidized iron minerals are presumably safeguarded against immediate arsenic contamination, due to strong sorption of arsenic onto iron minerals. However, preferential pumping of low-arsenic aquifers can destabilize the boundaries between these aquifers, pulling high-arsenic water into low-arsenic aquifers. We investigate this scenario in a hybrid field-column experiment in Bangladesh where naturally high-arsenic groundwater is pumped through sediment cores from a low-arsenic aquifer, and detailed aqueous and solid-phase measurements are used to constrain reactive transport modelling. Here we show that elevated groundwater arsenic concentrations are induced by sulfate reduction and the predicted formation of highly mobile, poorly sorbing thioarsenic species. This process suggests that contamination of currently pristine aquifers with arsenic can occur up to over 1.5 times faster than previously thought, leading to a deterioration of urgently needed water resources.
Collapse
Affiliation(s)
- Athena A. Nghiem
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
- Present address: Institute of Biogeochemistry and Pollutant Dynamics, Department of Environmental Systems Science, ETH Zurich, Zurich, Switzerland
- Present address: Eawag, Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland
| | - Henning Prommer
- CSIRO Environment, Wembley, Western Australia, Australia
- School of Earth Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - M. Rajib H. Mozumder
- Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
- Ramboll Environment & Health, Westford, MA, USA
| | - Adam Siade
- CSIRO Environment, Wembley, Western Australia, Australia
- School of Earth Sciences, University of Western Australia, Perth, Western Australia, Australia
| | - James Jamieson
- CSIRO Environment, Wembley, Western Australia, Australia
- School of Earth Sciences, University of Western Australia, Perth, Western Australia, Australia
| | | | - Alexander van Geen
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA
| | | |
Collapse
|
5
|
van Genuchten CM. The Enhanced Stability of Arsenic Coprecipitated with Magnetite during Aging: An XAS Investigation. Ind Eng Chem Res 2022. [DOI: 10.1021/acs.iecr.2c02357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Case M. van Genuchten
- Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Øster Voldgade 10, Copenhagen 1350, Denmark
| |
Collapse
|
6
|
Fan S, Gao Y, Lai B, Elzinga EJ, Yu S. Aerosol iron speciation and seasonal variation of iron oxidation state over the western Antarctic Peninsula. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 824:153890. [PMID: 35182624 DOI: 10.1016/j.scitotenv.2022.153890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 02/07/2022] [Accepted: 02/11/2022] [Indexed: 06/14/2023]
Abstract
The iron (Fe) speciation and oxidation state have been considered critical factors affecting Fe solubility in the atmosphere and bioavailability in the surface ocean. In this study, elemental composition and Fe speciation in aerosol samples collected at the Palmer Station in the West Antarctic Peninsula were determined using synchrotron-based X-ray fluorescence (XRF) and X-ray Absorption Near-Edge Structure (XANES) spectroscopy. The elemental composition of coarse-mode (>1 μm) Fe-containing particles suggests that the region's crustal emission is the primary source of aerosol Fe. The Fe minerals in these aerosol particles were predominantly hematite and biotite, but minor fractions of pyrite and ilmenite were observed as well. The Fe oxidation state showed an evident seasonal variation. The Fe(II) content accounted for 71% of the total Fe in the austral summer, while this fraction dropped to 60% in the austral winter. Multivariate linear models involving meteorological parameters suggested that the wind speed, relative humidity, and solar irradiance were the factors that significantly controlled the percentage of Fe(II) in the austral summer. On the contrary, no relationship was found between these factors and the Fe(II) percentage in the austral winter, suggesting that atmospheric photoreduction and regional dust emission were limited. Moreover, the snow depth was significantly (p < 0.05) correlated with the aerosol Fe concentration, confirming the limiting effect of snow/ice cover on the regional dust emission. Given that the Antarctic Peninsula has experienced rapid warming during recent decades, the ice-free areas in the Antarctic Peninsula may act as potential dust sources.
Collapse
Affiliation(s)
- Songyun Fan
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Yuan Gao
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102, USA.
| | - Barry Lai
- Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA
| | - Evert J Elzinga
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102, USA
| | - Shun Yu
- Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ 07102, USA
| |
Collapse
|
7
|
Klaes B, Wörner G, Thiele-Bruhn S, Arz HW, Struck J, Dellwig O, Groschopf N, Lorenz M, Wagner JF, Urrea OB, Lamy F, Kilian R. Element mobility related to rock weathering and soil formation at the westward side of the southernmost Patagonian Andes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 817:152977. [PMID: 35016939 DOI: 10.1016/j.scitotenv.2022.152977] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 12/25/2021] [Accepted: 01/04/2022] [Indexed: 06/14/2023]
Abstract
Rock weathering and pedogenesis are fundamental processes for element mobility in terrestrial bio-geochemical cycles and for the regulation of primary productivity in adjacent coastal marine ecosystems. Here, soils developed from volcanic ash under extreme climate conditions could play a particular role. We therefore investigated rock weathering, soil formation and the associated mobilization of trace elements and micronutrients in a pristine South Patagonian ecosystem. Weathered and unweathered basement lithologies, tephra of the 4.216 kyrs BP Mt. Burney eruption and four soil profiles are considered. The approach combines mineralogical (XRD, SEM) and inorganic geochemical (XRF, ICP-OES/MS) with organic geochemical analyses (TOC, TN, δ13C, δ15N, DOC extracts) of representative samples. Chemical weathering is quantified by mass balance calculations and 14C age constraints allow a correlation of pedogenic processes with the paleoenvironmental history of the area. Our data document that pedogenesis with initial peat formation occurred since ~2.5 kyrs BP. In these acidic peaty Andosols, intensive alteration of volcanic glass mobilized large quantities of elements, considerably surpassing leachates provided by basement rock weathering. Clay production is limited in favor of the formation of amorphous Al- and crystalline Fe-(hydr)oxides. However, tephra alteration, soil organic matter turnover rates, enhanced dissolved organic carbon export, and Fe-/Al-(hydr)oxide precipitation are closely linked and ultimately controlled by rainfall-induced water-level fluctuations, highlighting the dominant influence of the southern westerly wind belt. The transport of mobilized trace elements and micronutrients adsorbed onto suspended colloids (dissolved organic carbon, Al-humus complexes and Fe-(hydr)oxides) is redox-pH-dependent, highly variable and ultimately regulated by westerly intensity. Broader implications of this work include a new perspective on the climate-controlled micronutrient delivery for primary productivity in South Patagonian fjords, which is strongly affected by Andosol formation. Furthermore, a careful evaluation of 'ordinary' geochemical proxies in regional paleoenvironmental archives is needed to account for these unique pedogenic processes.
Collapse
Affiliation(s)
- Björn Klaes
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany; Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Gerhard Wörner
- Division of Geochemistry and Isotope Geology, GZG, Georg-August-University Göttingen, Goldschmidtstraße 1, 37077 Göttingen, Germany.
| | - Sören Thiele-Bruhn
- Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Helge Wolfgang Arz
- Marine Geology Department, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Seestraße 15, 18119 Rostock, Germany.
| | - Julian Struck
- Department of Physical Geography, Institute of Geography, Friedrich-Schiller-University Jena, Löbdergraben 32, 07743 Jena, Germany.
| | - Olaf Dellwig
- Marine Geology Department, Leibniz Institute for Baltic Sea Research Warnemünde (IOW), Seestraße 15, 18119 Rostock, Germany.
| | - Nora Groschopf
- Petrology Research Group, Institute of Geosciences, Johannes Gutenberg University Mainz, Johann-Joachim-Becher-Weg 21, 55128 Mainz, Germany.
| | - Marcel Lorenz
- Soil Science Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Jean-Frank Wagner
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Oscar Baeza Urrea
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany.
| | - Frank Lamy
- Alfred Wegener Institute (AWI) Bremerhaven, Am Alten Hafen 26, 27568 Bremerhaven, Germany.
| | - Rolf Kilian
- Geology Department, Trier University, Campus II (Geozentrum), Behringstraße 21, 54296 Trier, Germany; University of Magallanes, Avenida Bulnes, 01855 Punta Arenas, Chile
| |
Collapse
|
8
|
Wang S, Koedooder C, Zhang F, Kessler N, Eichner M, Shi D, Shaked Y. Colonies of the marine cyanobacterium Trichodesmium optimize dust utilization by selective collection and retention of nutrient-rich particles. iScience 2022; 25:103587. [PMID: 35005537 PMCID: PMC8718973 DOI: 10.1016/j.isci.2021.103587] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/01/2021] [Accepted: 12/06/2021] [Indexed: 12/11/2022] Open
Abstract
Trichodesmium, a globally important, N2-fixing, and colony-forming cyanobacterium, employs multiple pathways for acquiring nutrients from air-borne dust, including active dust collection. Once concentrated within the colony core, dust can supply Trichodesmium with nutrients. Recently, we reported a selectivity in particle collection enabling Trichodesmium to center iron-rich minerals and optimize its nutrient utilization. In this follow-up study we examined if colonies select Phosphorus (P) minerals. We incubated 1,200 Trichodesmium colonies from the Red Sea with P-free CaCO3, P-coated CaCO3, and dust, over an entire bloom season. These colonies preferably interacted, centered, and retained P-coated CaCO3 compared with P-free CaCO3. In both studies, Trichodesmium clearly favored dust over all other particles tested, whereas nutrient-free particles were barely collected or retained, indicating that the colonies sense the particle composition and preferably collect nutrient-rich particles. This unique ability contributes to Trichodesmium's current ecological success and may assist it to flourish in future warmer oceans. Natural Trichodesmium colonies collect and maintain dust within their colony core Using synthetic particles we tested if colonies select the particles they collect Colonies selectively collect and retain nutrient-rich over nutrient-free particles Selective collection of particles optimizes their nutrient acquisition from dust
Collapse
Affiliation(s)
- Siyuan Wang
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| | - Coco Koedooder
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel.,Israel Limnology and Oceanography Research, Haifa, Israel
| | - Futing Zhang
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel.,State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Nivi Kessler
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Meri Eichner
- Laboratory of Photosynthesis, Center Algatech, Institute of Microbiology of the Czech Academy of Sciences, Třeboň, Czech Republic
| | - Dalin Shi
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, People's Republic of China
| | - Yeala Shaked
- The Freddy and Nadine Herrmann Institute of Earth Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University of Jerusalem, Jerusalem, Israel.,The Interuniversity Institute for Marine Sciences in Eilat, Eilat, Israel
| |
Collapse
|
9
|
Schaefer MV, Abernathy MJ, Nguyen D, Cornell T, Ying SC. Firing Increases Arsenic Leaching from Ceramic Water Filters via Arsenic and Iron Phase Transformations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:9826-9835. [PMID: 34232034 PMCID: PMC8761037 DOI: 10.1021/acs.est.1c00169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Ceramic water filters (CWFs) are produced globally using local clay sources and can effectively remove bacterial pathogens during point-of-use water treatment. The ceramic production process involves firing clay mixed with burnout material at temperatures of 800-1100 °C, which induces mineralogical changes leading to increased arsenic (As) leaching from CWF material compared to source clay. Unfired clay and fired CWFs from Cambodia, Canada, and Mexico, CWF from Laos, and test-fired clay from the United States were analyzed to determine the extent of As leaching from CWFs that range in As (<1 to 16 mg kg-1) and iron (Fe) (0.6 to 5%) content. Deionized water, NaOH, HCl, and oxalate extractions showed that firing increased As solubility and decreased Fe solubility compared to unfired clay, with up to 8 mg kg-1 of water-soluble As in Cambodian CWFs. X-ray absorption spectra of the Cambodian clay and CWF showed a decrease in the Fe-O distance from 2.01 to 1.91 Å and decreased Fe coordination number from 6.3 to 4.6 after firing, indicating a decrease in Fe-O coordination. Arsenic(V) was the dominant species in Cambodia clay and CWF, existing primarily as a surface complex with average As-Fe distance of 3.28 Å in clay while in CWF As was either an outer-sphere As(V) phase or a discrete arsenate phase with no significant As-Fe scattering contribution within the resolution of the data. Improved understanding of molecular-scale processes that cause increased As leaching from CWFs provides a basis for assessing As leaching potential prior to CWF factory capital investment as well as engineered solutions (e.g., modified firing temperature, material amendments, and leaching prior to distribution) to mitigate As exposure from CWFs.
Collapse
Affiliation(s)
- Michael V Schaefer
- Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801, United States
| | - Macon J Abernathy
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521, United States
| | - Dominique Nguyen
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Thida Cornell
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| | - Samantha C Ying
- Environmental Toxicology Graduate Program, University of California, Riverside, California 92521, United States
- Department of Environmental Sciences, University of California, Riverside, California 92521, United States
| |
Collapse
|
10
|
Baccolo G, Delmonte B, Niles PB, Cibin G, Di Stefano E, Hampai D, Keller L, Maggi V, Marcelli A, Michalski J, Snead C, Frezzotti M. Jarosite formation in deep Antarctic ice provides a window into acidic, water-limited weathering on Mars. Nat Commun 2021; 12:436. [PMID: 33469027 PMCID: PMC7815727 DOI: 10.1038/s41467-020-20705-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/07/2020] [Indexed: 11/17/2022] Open
Abstract
Many interpretations have been proposed to explain the presence of jarosite within Martian surficial sediments, including the possibility that it precipitated within paleo-ice deposits owing to englacial weathering of dust. However, until now a similar geochemical process was not observed on Earth nor in other planetary settings. We report a multi-analytical indication of jarosite formation within deep ice. Below 1000 m depth, jarosite crystals adhering on residual silica-rich particles have been identified in the Talos Dome ice core (East Antarctica) and interpreted as products of weathering involving aeolian dust and acidic atmospheric aerosols. The progressive increase of ice metamorphism and re-crystallization with depth, favours the relocation and concentration of dust and the formation of acidic brines in isolated environments, allowing chemical reactions and mineral neo-formation to occur. This is the first described englacial diagenetic mechanism occurring in deep Antarctic ice and supports the ice-weathering model for jarosite formation on Mars, highlighting the geologic importance of paleo ice-related processes on this planet. Additional implications concern the preservation of dust-related signals in deep ice cores with respect to paleoclimatic reconstructions and the englacial history of meteorites from Antarctic blue ice fields. The authors report in-situ formation of jarosite witin the Talos Dome ice core (East Antarctica) and show that this ferric-potassium sulfate mineral is present in ice deeper than 1000 meters and progressively increases with depth. This has implications for the presence and formation mechanisms of jarosite observed on Mars.
Collapse
Affiliation(s)
- Giovanni Baccolo
- Department of Environmental and Earth Sciences, University of Milano-Bicocca, 20126, Milan, Italy. .,INFN, section of Milano-Bicocca, 20126, Milan, Italy.
| | - Barbara Delmonte
- Department of Environmental and Earth Sciences, University of Milano-Bicocca, 20126, Milan, Italy
| | - P B Niles
- NASA Johnson Space Center, Houston, TX, 77058, USA
| | - Giannantonio Cibin
- Diamond Light Source, Harwell Science and Innovation Campus, Didcot, OX11 0DE, UK
| | - Elena Di Stefano
- Department of Environmental and Earth Sciences, University of Milano-Bicocca, 20126, Milan, Italy.,INFN, section of Milano-Bicocca, 20126, Milan, Italy.,Department of Physical, Earth and Environmental Sciences, University of Siena, 53100, Siena, Italy
| | - Dariush Hampai
- Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044, Frascati, Italy
| | | | - Valter Maggi
- Department of Environmental and Earth Sciences, University of Milano-Bicocca, 20126, Milan, Italy.,INFN, section of Milano-Bicocca, 20126, Milan, Italy
| | - Augusto Marcelli
- Laboratori Nazionali di Frascati, Istituto Nazionale di Fisica Nucleare, 00044, Frascati, Italy.,Rome International Center for Materials Science - Superstripes, 00185, Rome, Italy
| | - Joseph Michalski
- Department of Earth Sciences, University of Hong Kong, Hong Kong, Hong Kong
| | | | | |
Collapse
|
11
|
Nghiem AA, Shen Y, Stahl M, Sun J, Haque E, DeYoung B, Nguyen KN, Mai TT, Trang PTK, Pham HV, Mailloux B, Harvey CF, van Geen A, Bostick BC. Aquifer-Scale Observations of Iron Redox Transformations in Arsenic-Impacted Environments to Predict Future Contamination. ENVIRONMENTAL SCIENCE & TECHNOLOGY LETTERS 2020; 7:916-922. [PMID: 33604397 PMCID: PMC7886273 DOI: 10.1021/acs.estlett.0c00672] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Iron oxides control the mobility of a host of contaminants in aquifer systems, and the microbial reduction of iron oxides in the subsurface is linked to high levels of arsenic in groundwater that affects greater than 150 million people globally. Paired observations of groundwater and solid-phase aquifer composition are critical to understand spatial and temporal trends in contamination and effectively manage changing water resources, yet field-representative mineralogical data are sparse across redox gradients relevant to arsenic contamination. We characterize iron mineralogy using X-ray absorption spectroscopy across a natural gradient of groundwater arsenic contamination in Vietnam. Hierarchical cluster analysis classifies sediments into meaningful groups delineating weathering and redox changes, diagnostic of depositional history, in this first direct characterization of redox transformations in the field. Notably, these groupings reveal a signature of iron minerals undergoing active reduction before the onset of arsenic contamination in groundwater. Pleistocene sediments undergoing postdepositional reduction may be more extensive than previously recognized due to previous misclassification. By upscaling to similar environments in South and Southeast Asia via multinomial logistic regression modeling, we show that active iron reduction, and therefore susceptibility to future arsenic contamination, is more widely distributed in presumably pristine aquifers than anticipated.
Collapse
Affiliation(s)
- Athena A Nghiem
- Department of Earth and Environmental Sciences and Lamont-Doherty Earth Observatory, Columbia University, New York, New York 10027, United States
| | - Yating Shen
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, United States; National Research Center of Geoanalysis, Chinese Academy of Geological Sciences, Beijing, China
| | - Mason Stahl
- Department of Geology, Union College, Schenectady, New York 12308, United States
| | - Jing Sun
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang China
| | - Ezazul Haque
- Department of Occupational and Environmental Health, University of Iowa, Iowa City, Iowa 52242, United States
| | - Beck DeYoung
- Department of Geology, Union College, Schenectady, New York 12308, United States
| | - Khue N Nguyen
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, United States
| | - Tran Thi Mai
- Key Laboratory of Analytical Technology for Environmental Quality and Food Safety Control (KLATEFOS), VNU University of Science, Vietnam National University, Hanoi, Vietnam
| | - Pham Thi Kim Trang
- Key Laboratory of Analytical Technology for Environmental Quality and Food Safety Control (KLATEFOS), VNU University of Science, Vietnam National University, Hanoi, Vietnam
| | - Hung Viet Pham
- Key Laboratory of Analytical Technology for Environmental Quality and Food Safety Control (KLATEFOS), VNU University of Science, Vietnam National University, Hanoi, Vietnam
| | - Brian Mailloux
- Department of Environmental Sciences, Barnard College, New York, New York 10027, United States
| | - Charles F Harvey
- Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Alexander van Geen
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, United States
| | - Benjamin C Bostick
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, United States
| |
Collapse
|
12
|
Struve T, Pahnke K, Lamy F, Wengler M, Böning P, Winckler G. A circumpolar dust conveyor in the glacial Southern Ocean. Nat Commun 2020; 11:5655. [PMID: 33168803 PMCID: PMC7652835 DOI: 10.1038/s41467-020-18858-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 09/14/2020] [Indexed: 11/22/2022] Open
Abstract
The increased flux of soluble iron (Fe) to the Fe-deficient Southern Ocean by atmospheric dust is considered to have stimulated the net primary production and carbon export, thus promoting atmospheric CO2 drawdown during glacial periods. Yet, little is known about the sources and transport pathways of Southern Hemisphere dust during the Last Glacial Maximum (LGM). Here we show that Central South America (~24‒32°S) contributed up to ~80% of the dust deposition in the South Pacific Subantarctic Zone via efficient circum-Antarctic dust transport during the LGM, whereas the Antarctic Zone was dominated by dust from Australia. This pattern is in contrast to the modern/Holocene pattern, when South Pacific dust fluxes are thought to be primarily supported by Australian sources. Our findings reveal that in the glacial Southern Ocean, Fe fertilization critically relies on the dynamic interaction of changes in dust-Fe sources in Central South America with the circumpolar westerly wind system. Dust deposition brings iron that fuels ocean productivity, a connection impacting climate over geological time. Here the authors use sediment cores to show that in contrast to dynamics today, during the last glacial maximum westerly winds shuttled dust from Australia and South America around Antarctica and into the South Pacific.
Collapse
Affiliation(s)
- Torben Struve
- Marine Isotope Geochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, 26129, Oldenburg, Germany.
| | - Katharina Pahnke
- Marine Isotope Geochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, 26129, Oldenburg, Germany
| | - Frank Lamy
- Alfred Wegener Institute for Polar and Marine Research, 27568, Bremerhaven, Germany
| | - Marc Wengler
- Alfred Wegener Institute for Polar and Marine Research, 27568, Bremerhaven, Germany
| | - Philipp Böning
- Marine Isotope Geochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, 26129, Oldenburg, Germany
| | - Gisela Winckler
- Lamont-Doherty Earth Observatory of Columbia University, Palisades, New York, 10964, USA.,Department of Earth and Environmental Sciences, Columbia University, New York, New York, 10027, USA
| |
Collapse
|
13
|
Mozumder MRH, Bostick BC, Selim M, Islam MA, Shoenfelt EM, Ellis T, Mailloux BJ, Choudhury I, Ahmed KM, van Geen A. Similar retardation of arsenic in gray Holocene and orange Pleistocene sediments: Evidence from field-based column experiments in Bangladesh. WATER RESEARCH 2020; 183:116081. [PMID: 32784107 DOI: 10.1016/j.watres.2020.116081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/15/2020] [Accepted: 06/16/2020] [Indexed: 06/11/2023]
Abstract
Groundwater flow has the potential to introduce arsenic (As) in previously uncontaminated aquifers. The extent to which As transport is retarded by adsorption is particularly relevant in Bangladesh where low-As wells offer the best chance of reducing chronic exposure to As of a large rural population dependent on groundwater. In this study, column experiments were conducted with intact cores in the field to measure As retardation. Freshly collected cores of reduced iron (Fe-II) dominated gray sediment of Holocene age as well as oxidized Fe (III)-coated orange sediment of Pleistocene age were eluted at pore-water velocities of 40-230 cm/day with anoxic groundwater pumped directly from a well and containing 320 μg/L As. Up to 100 μg/L As was immediately released from gray sand but the main As breakthrough for both gray and orange sand occurred between 30 and 70 pore volumes, depending on flow rate. The early release of As from gray sand is attributed to the presence of a weakly bound pool of As. The sorption of As was kinetically limited in both gray and orange sand columns. We used a reversible multi-reaction transport model to simulate As breakthrough curves while keeping the model parameters as constant as possible. Contrary to the notion that dissolved As is sorbed more strongly to orange sands, we show that As was similarly retarded in both gray and orange sands in the field.
Collapse
Affiliation(s)
- M Rajib H Mozumder
- Lamont-Doherty Earth Observatory of Columbia University, NY, 10964, USA; Now at Gradient, One Beacon Street, 17th Floor, Boston, MA, 02108, USA.
| | | | - Magdi Selim
- School of Plant, Environmental, and Soil Sciences, Louisiana State University AgCenter, Baton Rouge, LA, 70803, USA
| | - M Atikul Islam
- Department of Geology, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Elizabeth M Shoenfelt
- Lamont-Doherty Earth Observatory of Columbia University, NY, 10964, USA; Now at Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Tyler Ellis
- Lamont-Doherty Earth Observatory of Columbia University, NY, 10964, USA
| | - Brian J Mailloux
- Environmental Science, Barnard College, New York, NY, 10027, USA
| | - Imtiaz Choudhury
- Department of Geology, University of Dhaka, Dhaka, 1000, Bangladesh
| | - Kazi M Ahmed
- Department of Geology, University of Dhaka, Dhaka, 1000, Bangladesh
| | | |
Collapse
|
14
|
Galbraith ED, Skinner LC. The Biological Pump During the Last Glacial Maximum. ANNUAL REVIEW OF MARINE SCIENCE 2020; 12:559-586. [PMID: 31899673 DOI: 10.1146/annurev-marine-010419-010906] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Much of the global cooling during ice ages arose from changes in ocean carbon storage that lowered atmospheric CO2. A slew of mechanisms, both physical and biological, have been proposed as key drivers of these changes. Here we discuss the current understanding of these mechanisms with a focus on how they altered the theoretically defined soft-tissue and biological disequilibrium carbon storage at the peak of the last ice age. Observations and models indicate a role for Antarctic sea ice through its influence on ocean circulation patterns, but other mechanisms, including changes in biological processes, must have been important as well, and may have been coordinated through links with global air temperature. Further research is required to better quantify the contributions of the various mechanisms, and there remains great potential to use the Last Glacial Maximum and the ensuing global warming as natural experiments from which to learn about climate-driven changes in the marine ecosystem.
Collapse
Affiliation(s)
- Eric D Galbraith
- Department of Earth and Planetary Sciences, McGill University, Montreal H3A 0E8, Canada;
- Institut de Ciència i Tecnologia Ambientals (ICTA-UAB), Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
| | - Luke C Skinner
- Godwin Laboratory for Palaeoclimate Research, Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, United Kingdom;
| |
Collapse
|
15
|
Corliss BA, Delalio LJ, Stevenson Keller TC, Keller AS, Keller DA, Corliss BH, Beers JM, Peirce SM, Isakson BE. Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver. Front Physiol 2019; 10:1389. [PMID: 31780954 PMCID: PMC6861181 DOI: 10.3389/fphys.2019.01389] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 10/24/2019] [Indexed: 12/16/2022] Open
Abstract
Frigid temperatures of the Southern Ocean are known to be an evolutionary driver in Antarctic fish. For example, many fish have reduced red blood cell (RBC) concentration to minimize vascular resistance. Via the oxygen-carrying protein hemoglobin, RBCs contain the vast majority of the body's iron, which is known to be a limiting nutrient in marine ecosystems. Since lower RBC levels also lead to reduced iron requirements, we hypothesize that low iron availability was an additional evolutionary driver of Antarctic fish speciation. Antarctic Icefish of the family Channichthyidae are known to have an extreme alteration of iron metabolism due to loss of RBCs and two iron-binding proteins, hemoglobin and myoglobin. Loss of hemoglobin is considered a maladaptive trait allowed by relaxation of predator selection since extreme adaptations are required to compensate for the loss of oxygen-carrying capacity. However, iron dependency minimization may have driven hemoglobin loss instead of a random evolutionary event. Given the variety of functions that hemoglobin serves in the endothelium, we suspected the protein corresponding to the 3' truncated Hbα fragment (Hbα-3'f) that was not genetically excluded by icefish may still be expressed as a protein. Using whole mount confocal microscopy, we show that Hbα-3'f is expressed in the vascular endothelium of icefish retina, suggesting this Hbα fragment may still serve an important role in the endothelium. These observations support a novel hypothesis that iron minimization could have influenced icefish speciation with the loss of the iron-binding portion of Hbα in Hbα-3'f, as well as hemoglobin β and myoglobin.
Collapse
Affiliation(s)
- Bruce A Corliss
- Biomedical Engineering Department, University of Virginia, Charlottesville, VA, United States
| | - Leon J Delalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - T C Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Alexander S Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States
| | | | - Bruce H Corliss
- Graduate School of Oceanography, University of Rhode Island, Kingston, RI, United States
| | - Jody M Beers
- Department of Biology, College of Charleston, Charleston, SC, United States
| | - Shayn M Peirce
- Biomedical Engineering Department, University of Virginia, Charlottesville, VA, United States
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, United States.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA, United States
| |
Collapse
|
16
|
Wadham JL, Hawkings JR, Tarasov L, Gregoire LJ, Spencer RGM, Gutjahr M, Ridgwell A, Kohfeld KE. Ice sheets matter for the global carbon cycle. Nat Commun 2019; 10:3567. [PMID: 31417076 PMCID: PMC6695407 DOI: 10.1038/s41467-019-11394-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 07/09/2019] [Indexed: 11/09/2022] Open
Abstract
The cycling of carbon on Earth exerts a fundamental influence upon the greenhouse gas content of the atmosphere, and hence global climate over millennia. Until recently, ice sheets were viewed as inert components of this cycle and largely disregarded in global models. Research in the past decade has transformed this view, demonstrating the existence of uniquely adapted microbial communities, high rates of biogeochemical/physical weathering in ice sheets and storage and cycling of organic carbon (>104 Pg C) and nutrients. Here we assess the active role of ice sheets in the global carbon cycle and potential ramifications of enhanced melt and ice discharge in a warming world.
Collapse
Affiliation(s)
- J L Wadham
- University of Bristol, Bristol, BS8 1TH, UK.
| | - J R Hawkings
- National High Magnetic Field Lab and Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, 32306, USA
- German Research Centre for Geosciences GFZ, 14473, Potsdam, Germany
| | - L Tarasov
- Memorial University, St. John's, NF, A1B 3X9, Canada
| | | | - R G M Spencer
- National High Magnetic Field Lab and Earth, Ocean and Atmospheric Sciences, Florida State University, Tallahassee, FL, 32306, USA
| | | | - A Ridgwell
- University of California, Riverside, CA, 94720, USA
| | - K E Kohfeld
- Simon Fraser University, Burnaby, BC, 8888, Canada
| |
Collapse
|
17
|
Khatiwala S, Schmittner A, Muglia J. Air-sea disequilibrium enhances ocean carbon storage during glacial periods. SCIENCE ADVANCES 2019; 5:eaaw4981. [PMID: 31206024 PMCID: PMC6561735 DOI: 10.1126/sciadv.aaw4981] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Accepted: 05/09/2019] [Indexed: 06/09/2023]
Abstract
The prevailing hypothesis for lower atmospheric carbon dioxide (CO2) concentrations during glacial periods is an increased efficiency of the ocean's biological pump. However, tests of this and other hypotheses have been hampered by the difficulty to accurately quantify ocean carbon components. Here, we use an observationally constrained earth system model to precisely quantify these components and the role that different processes play in simulated glacial-interglacial CO2 variations. We find that air-sea disequilibrium greatly amplifies the effects of cooler temperatures and iron fertilization on glacial ocean carbon storage even as the efficiency of the soft-tissue biological pump decreases. These two processes, which have previously been regarded as minor, explain most of our simulated glacial CO2 drawdown, while ocean circulation and sea ice extent, hitherto considered dominant, emerge as relatively small contributors.
Collapse
Affiliation(s)
- S. Khatiwala
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - A. Schmittner
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - J. Muglia
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| |
Collapse
|