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Sarathchandraprasad T, Tiwari M, Kumar V, Sherin S, Yadava MG. Glacial interglacial variations in the natural iron fertilization during the low sea ice periods along the eastern continental margin of Antarctica. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 954:176745. [PMID: 39383957 DOI: 10.1016/j.scitotenv.2024.176745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 09/28/2024] [Accepted: 10/03/2024] [Indexed: 10/11/2024]
Abstract
The Southern Ocean sequesters atmospheric CO2 through biological pumps, though its driving factors are debated. Modern productivity is regulated by natural iron fertilization from micronutrient influx through dust, regeneration, and Antarctic glaciers and sea ice melting (ice melt). The productivity along the eastern Antarctic continental margin was low during the last glacial period and gradually increased through the deglacial to Late Holocene, marked by distinct productivity peaks. The micronutrients also varied similarly, with reduced glacial influx and an increase in the Holocene, which may cause productivity peaks. Therefore, the coherence of enhanced productivity and micronutrient influx is considered as enhanced iron fertilization period. The productivity peaks declined within ∼1.5 kyr, mostly due to the Ekman transport and sea ice formation. Along with ice melt, the independent weathering pattern that responds with glacial- interglacial ice volume changes suggest the source of micronutrients is not terrigenous. Shelf interaction of oceanic currents can influence the water column nutrient stock significantly, while its utilization occurs during reduced ice periods (low sea ice and high glacier melting) for productivity. Therefore, enhanced natural iron fertilization periods are considered as ice low periods that occurred in a periodicity of 2 kyrs, at ∼7.5 kyr BP, ∼5.5 kyr BP, ∼4 kyr BP, ∼ 2.5 kyr BP, and ∼0.5 kyr BP, likely due to the combined effects of atmospheric and oceanographic factors driven by the high amplitude regional temperature variability during the mid to late Holocene.
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Affiliation(s)
- T Sarathchandraprasad
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Vasco Da Gama, Goa 403804, India
| | - Manish Tiwari
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Vasco Da Gama, Goa 403804, India.
| | - Vikash Kumar
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Vasco Da Gama, Goa 403804, India
| | - Sharmila Sherin
- National Centre for Polar and Ocean Research, Ministry of Earth Sciences, Vasco Da Gama, Goa 403804, India
| | - M G Yadava
- Geoscience Division, Physical Research Laboratory, Navrangapura, Ahmedabad 380009, India
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2
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Chen J, Zhang D, Fu Y, Wang J, Cui X, Qu-Zong CR, Zhang Q, Jin C, Duo B. Microscopic and spectroscopic analysis of atmospheric iron-containing single particles in Lhasa, Tibet. J Environ Sci (China) 2024; 141:40-50. [PMID: 38408833 DOI: 10.1016/j.jes.2023.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 02/28/2024]
Abstract
The Tibetan Plateau, known as the "Third Pole", is currently in a state of perturbation caused by intensified human activity. In this study, 56 samples were obtained at the five sampling sites in typical area of Lhasa city and their physical and chemical properties were investigated by TEM/EDS, STXM, and NEXAFS spectroscopy. After careful examination of 3387 single particles, the results showed that Fe should be one of the most frequent metal elements. The Fe-containing single particles in irregular shape and micrometer size was about 7.8% and might be mainly from local sources. Meanwhile, the Fe was located on the subsurface of single particles and might be existed in the form of iron oxide. Interestingly, the core-shell structure of iron-containing particles were about 38.8% and might be present as single-, dual- or triple-core shell structure and multi-core shell structure with the Fe/Si ratios of 17.5, 10.5, 2.9 and 1.2, respectively. Meanwhile, iron and manganese were found to coexist with identical distributions in the single particles, which might induce a synergistic effect between iron and manganese in catalytic oxidation. Finally, the solid spherical structure of Fe-containing particles without an external layer were about 53.4%. The elements of Fe and Mn were co-existed, and might be presented as iron oxide-manganese oxide-silica composite. Moreover, the ferrous and ferric forms of iron might be co-existed. Such information can be valuable in expanding our understanding of Fe-containing particles in the Tibetan Plateau atmosphere.
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Affiliation(s)
- Junyu Chen
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Daobin Zhang
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Yiran Fu
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Jinhu Wang
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Xiaomei Cui
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Ci-Ren Qu-Zong
- School of Ecology and Environment, Tibet University, Lhasa 850000, China; Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiangying Zhang
- School of Ecology and Environment, Tibet University, Lhasa 850000, China
| | - Chan Jin
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
| | - Bu Duo
- School of Ecology and Environment, Tibet University, Lhasa 850000, China.
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Mushtaq N, Farooqi A, Khattak JA, Hussain I, Mailloux B, Bostick BC, Nghiem A, Ellis T, van Geen A. Elevated arsenic concentrations in groundwater of the Upper Indus Plain of Pakistan across a range of redox conditions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168574. [PMID: 38000757 DOI: 10.1016/j.scitotenv.2023.168574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 10/30/2023] [Accepted: 11/12/2023] [Indexed: 11/26/2023]
Abstract
Groundwater of the Ravi River floodplain is particularly elevated in arsenic (As) on both sides of the Pakistan-India border. To understand this pattern, 14 sites were drilled to 12-30 m depth across floodplains and doabs of Pakistan after testing over 20,000 wells. Drill cuttings were collected at 1.5 m intervals, 132 of which were sand overlain by 77 intervals of clay and/or silt. Radiocarbon dating of clay indicates deposition of the aquifer sands tapped by wells 20-30 kyr ago. Most (85 %) of the sand samples were gray in color, indicating partial reduction to Fe(II) oxides, whereas most (92 %) of the clay and/or silt samples were orange. Associations between groundwater electrical conductivity, dissolved Fe, sulfate, and nitrate suggest that wells can be elevated (>10 μg/L) in As in the region due to either reductive dissolution of Fe oxides, evaporative concentration, or alkali desorption. In the Ravi floodplain, 47 % of 6445 wells tested contain >10 μg/L As compared to only 9 % of 14,165 tested wells in other floodplains and doabs. The As content of aquifer sands in the Ravi floodplain of Pakistan averages 4 ± 4 mg/kg (n = 66) and is higher than the average of 2 ± 2 mg/kg (n = 51) for aquifer sands outside the Ravi. Synchrotron spectroscopy and column-based speciation indicate predominance of As(V) over As(III) in both aquifer sands and groundwater. Whereas multiple processes may be responsible for elevated levels of As in groundwater across the region, spatial heterogeneity in groundwater As concentrations in the Ravi floodplain seems linked to variations in As concentrations in aquifer sands. Regulation by the solid phase may limit variations in groundwater As over time in response to natural and human-induced changes in hydrology. This means spatial heterogeneity could be taken advantage of to lower the exposure across the region with more testing and targeted drilling.
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Affiliation(s)
- Nisbah Mushtaq
- Environmental Hydrogeochemistry Laboratory, Department of Environmental Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Abida Farooqi
- Environmental Hydrogeochemistry Laboratory, Department of Environmental Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan.
| | - Junaid Ali Khattak
- Environmental Hydrogeochemistry Laboratory, Department of Environmental Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Ishtiaque Hussain
- Environmental Hydrogeochemistry Laboratory, Department of Environmental Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Brian Mailloux
- Environmental Sciences Department, Barnard College, New York, USA
| | | | - Athena Nghiem
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
| | - Tyler Ellis
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
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Chen L, Di P, Feng J, Chen D, Li N, Li Y. Impact of dust deposition on the growth of marine autotrophic and heterotrophic microorganisms: Evidence from the South China Sea. MARINE POLLUTION BULLETIN 2023; 197:115749. [PMID: 37924735 DOI: 10.1016/j.marpolbul.2023.115749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 10/29/2023] [Accepted: 11/01/2023] [Indexed: 11/06/2023]
Abstract
Aeolian dust can provide nutrients for the ocean and affect the growth of phytoplankton. However, the impacts of dust deposition on autotrophic and heterotrophic microorganisms have rarely been studied. In this study, we conducted two microcosm experiments in the low-nutrient and low-chlorophyll environment of the South China Sea and found that dust did not stimulate the abundance of autotrophic and heterotrophic microorganisms. Our results show that dust contains most of the unreacted iron-bearing minerals, and thus provides limited bioavailable iron and nitrogen for bacterioplankton and phytoplankton growth. These results elucidate the overlooked impacts of the properties of the iron-bearing minerals in aeolian dust on microbial communities, which may play an important role in marine ecosystems and climate change.
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Affiliation(s)
- Linying Chen
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China
| | - Pengfei Di
- Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 510301, China
| | - Junxi Feng
- Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, Ministry of Natural Resources, Guangzhou 510075, China
| | - Duofu Chen
- Shanghai Engineering Research Center of Hadal Science and Technology, College of Marine Sciences, Shanghai Ocean University, Shanghai 201306, China
| | - Niu Li
- Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 510301, China.
| | - Yazi Li
- Guangdong Provincial Key Laboratory of Single Cell Technology and Application, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
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Zan J, Maher B, Yamazaki T, Fang X, Han W, Kang J, Hu Z. Mid-Pleistocene links between Asian dust, Tibetan glaciers, and Pacific iron fertilization. Proc Natl Acad Sci U S A 2023; 120:e2304773120. [PMID: 37279267 PMCID: PMC10268273 DOI: 10.1073/pnas.2304773120] [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: 03/23/2023] [Accepted: 05/08/2023] [Indexed: 06/08/2023] Open
Abstract
Increasing Asian dust fluxes, associated with late Cenozoic cooling and intensified glaciations, are conventionally thought to drive iron fertilization of phytoplankton productivity in the North Pacific, contributing to ocean carbon storage and drawdown of atmospheric CO2. During the early Pleistocene glaciations, however, productivity remained low despite higher Asian dust fluxes, only displaying glacial stage increases after the mid-Pleistocene climate transition (~800 ka B.P.). We solve this paradox by analyzing an Asian dust sequence, spanning the last 3.6 My, from the Tarim Basin, identifying a major switch in the iron composition of the dust at ~800 ka, associated with expansion of Tibetan glaciers and enhanced production of freshly ground rock minerals. This compositional shift in the Asian dust was recorded synchronously in the downwind, deep sea sediments of the central North Pacific. The switch from desert dust, containing stable, highly oxidized iron, to glacial dust, richer in reactive reduced iron, coincided with increased populations of silica-producing phytoplankton in the equatorial North Pacific and increased primary productivity in more northerly locations, such as the South China Sea. We calculate that potentially bioavailable Fe2+ flux to the North Pacific was more than doubled after the switch to glacially- sourced dust. These findings indicate a positive feedback between Tibetan glaciations, glaciogenic production of dust with enhanced iron bioavailability, and changes in North Pacific iron fertilization. Notably, this strengthened link between climate and eolian dust coincided with the mid-Pleistocene transition to increased storage of C in the glacial North Pacific and more intense northern hemisphere glaciations.
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Affiliation(s)
- Jinbo Zan
- State Key Laboratory of Tibetan Plateau Earth System and Resources Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing100101China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing1000449China
| | - Barbara A. Maher
- Centre for Environmental Magnetism & Palaeomagnetism, Lancaster Environment Centre, University of Lancaster,LancasterLA1 4YQ, UK
| | - Toshitsugu Yamazaki
- Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa277-8564, Japan
| | - Xiaomin Fang
- State Key Laboratory of Tibetan Plateau Earth System and Resources Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing100101China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing1000449China
| | - Wenxia Han
- School of Resource and Environmental Sciences, Linyi University,276000Linyi, China
| | - Jian Kang
- State Key Laboratory of Tibetan Plateau Earth System and Resources Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing100101China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing1000449China
| | - Zhe Hu
- State Key Laboratory of Tibetan Plateau Earth System and Resources Environment, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing100101China
- College of Resources and Environment, University of Chinese Academy of Sciences, Beijing1000449China
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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
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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: 2] [Impact Index Per Article: 1.0] [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.
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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
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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.
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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
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Gao X, Bowler C, Kazamia E. Iron metabolism strategies in diatoms. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:2165-2180. [PMID: 33693565 PMCID: PMC7966952 DOI: 10.1093/jxb/eraa575] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 03/03/2021] [Indexed: 05/28/2023]
Abstract
Diatoms are one of the most successful group of photosynthetic eukaryotes in the contemporary ocean. They are ubiquitously distributed and are the most abundant primary producers in polar waters. Equally remarkable is their ability to tolerate iron deprivation and respond to periodic iron fertilization. Despite their relatively large cell sizes, diatoms tolerate iron limitation and frequently dominate iron-stimulated phytoplankton blooms, both natural and artificial. Here, we review the main iron use strategies of diatoms, including their ability to assimilate and store a range of iron sources, and the adaptations of their photosynthetic machinery and architecture to iron deprivation. Our synthesis relies on published literature and is complemented by a search of 82 diatom transcriptomes, including information collected from seven representatives of the most abundant diatom genera in the world's oceans.
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Affiliation(s)
- Xia Gao
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Chris Bowler
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
| | - Elena Kazamia
- Institut de Biologie de l’ENS (IBENS), Département de Biologie, École Normale Supérieure, CNRS, INSERM, Université PSL, 75005 Paris, France
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Laufer-Meiser K, Michaud AB, Maisch M, Byrne JM, Kappler A, Patterson MO, Røy H, Jørgensen BB. Potentially bioavailable iron produced through benthic cycling in glaciated Arctic fjords of Svalbard. Nat Commun 2021; 12:1349. [PMID: 33649339 PMCID: PMC7921405 DOI: 10.1038/s41467-021-21558-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/28/2021] [Indexed: 01/31/2023] Open
Abstract
The Arctic has the highest warming rates on Earth. Glaciated fjord ecosystems, which are hotspots of carbon cycling and burial, are extremely sensitive to this warming. Glaciers are important for the transport of iron from land to sea and supply this essential nutrient to phytoplankton in high-latitude marine ecosystems. However, up to 95% of the glacially-sourced iron settles to sediments close to the glacial source. Our data show that while 0.6-12% of the total glacially-sourced iron is potentially bioavailable, biogeochemical cycling in Arctic fjord sediments converts the glacially-derived iron into more labile phases, generating up to a 9-fold increase in the amount of potentially bioavailable iron. Arctic fjord sediments are thus an important source of potentially bioavailable iron. However, our data suggests that as glaciers retreat onto land the flux of iron to the sediment-water interface may be reduced. Glacial retreat therefore likely impacts iron cycling in coastal marine ecosystems.
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Affiliation(s)
- Katja Laufer-Meiser
- grid.7048.b0000 0001 1956 2722Center for Geomicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark ,grid.15649.3f0000 0000 9056 9663Present Address: GEOMAR, Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Alexander B. Michaud
- grid.7048.b0000 0001 1956 2722Center for Geomicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark ,grid.296275.d0000 0000 9516 4913Present Address: Bigelow Laboratory for Ocean Sciences, Maine, USA
| | - Markus Maisch
- grid.10392.390000 0001 2190 1447Center for Applied Geosciences, University of Tübingen, Tübingen, Germany
| | - James M. Byrne
- grid.10392.390000 0001 2190 1447Center for Applied Geosciences, University of Tübingen, Tübingen, Germany ,grid.5337.20000 0004 1936 7603Present Address: School of Earth Sciences, University of Bristol, Wills Memorial Building, Bristol, UK
| | - Andreas Kappler
- grid.10392.390000 0001 2190 1447Center for Applied Geosciences, University of Tübingen, Tübingen, Germany ,grid.15649.3f0000 0000 9056 9663Present Address: GEOMAR, Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Molly O. Patterson
- grid.264260.40000 0001 2164 4508Department of Geological Sciences and Environmental Studies, Binghamton University, New York, USA
| | - Hans Røy
- grid.7048.b0000 0001 1956 2722Center for Geomicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Bo Barker Jørgensen
- grid.7048.b0000 0001 1956 2722Center for Geomicrobiology, Department of Biology, Aarhus University, Aarhus, Denmark
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11
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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.
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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
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Pryer HV, Hawkings JR, Wadham JL, Robinson LF, Hendry KR, Hatton JE, Kellerman AM, Bertrand S, Gill‐Olivas B, Marshall MG, Brooker RA, Daneri G, Häussermann V. The Influence of Glacial Cover on Riverine Silicon and Iron Exports in Chilean Patagonia. GLOBAL BIOGEOCHEMICAL CYCLES 2020; 34:e2020GB006611. [PMID: 33519063 PMCID: PMC7818384 DOI: 10.1029/2020gb006611] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 09/27/2020] [Accepted: 11/12/2020] [Indexed: 06/12/2023]
Abstract
Glaciated environments have been highlighted as important sources of bioavailable nutrients, with inputs of glacial meltwater potentially influencing productivity in downstream ecosystems. However, it is currently unclear how riverine nutrient concentrations vary across a spectrum of glacial cover, making it challenging to accurately predict how terrestrial fluxes will change with continued glacial retreat. Using 40 rivers in Chilean Patagonia as a unique natural laboratory, we investigate how glacial cover affects riverine Si and Fe concentrations, and infer how exports of these bioessential nutrients may change in the future. Dissolved Si (as silicic acid) and soluble Fe (<0.02 μm) concentrations were relatively low in glacier-fed rivers, whereas concentrations of colloidal-nanoparticulate (0.02-0.45 μm) Si and Fe increased significantly as a function of glacial cover. These colloidal-nanoparticulate phases were predominately composed of aluminosilicates and Fe-oxyhydroxides, highlighting the need for size-fractionated analyses and further research to quantify the lability of colloidal-nanoparticulate species. We also demonstrate the importance of reactive particulate (>0.45 μm) phases of both Si and Fe, which are not typically accounted for in terrestrial nutrient budgets but can dominate riverine exports. Dissolved Si and soluble Fe yield estimates showed no trend with glacial cover, suggesting no significant change in total exports with continued glacial retreat. However, yields of colloidal-nanoparticulate and reactive sediment-bound Si and Fe were an order of magnitude greater in highly glaciated catchments and showed significant positive correlations with glacial cover. As such, regional-scale exports of these phases are likely to decrease as glacial cover disappears across Chilean Patagonia, with potential implications for downstream ecosystems.
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Affiliation(s)
- Helena V. Pryer
- Bristol Glaciology Centre, Department of Geographical SciencesUniversity of BristolBristolUK
- School of Earth SciencesUniversity of BristolBristolUK
| | - Jon R. Hawkings
- Department of Earth, Ocean and Atmospheric SciencesFlorida State UniversityTallahasseeFLUSA
- German Research Centre for Geosciences GFZPotsdamGermany
| | - Jemma L. Wadham
- Bristol Glaciology Centre, Department of Geographical SciencesUniversity of BristolBristolUK
| | | | | | | | - Anne M. Kellerman
- Department of Earth, Ocean and Atmospheric SciencesFlorida State UniversityTallahasseeFLUSA
| | | | - Beatriz Gill‐Olivas
- Bristol Glaciology Centre, Department of Geographical SciencesUniversity of BristolBristolUK
| | - Matthew G. Marshall
- Bristol Glaciology Centre, Department of Geographical SciencesUniversity of BristolBristolUK
| | | | - Giovanni Daneri
- Centro de Investigación en Ecosistemas de la PatagoniaCoyhaiqueChile
- COPAS Sur‐AustralUniversidad de ConcepciónConcepciónChile
| | - Vreni Häussermann
- Huinay Scientific Field StationPontificia Universidad Católica de ValparaísoValparaísoChile
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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.
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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
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Highly bioavailable dust-borne iron delivered to the Southern Ocean during glacial periods. Proc Natl Acad Sci U S A 2018; 115:11180-11185. [PMID: 30322933 PMCID: PMC6217405 DOI: 10.1073/pnas.1809755115] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dust-borne iron fertilization of Southern Ocean phytoplankton contributes to lower glacial atmospheric CO2. Previous studies evaluating the impact of dust on climate estimate bioavailable iron using total iron fluxes in sediment cores. Thus, all iron is considered equally bioavailable over geologic time, despite evidence that glaciers mobilize highly bioavailable iron from bedrock, which winds can deliver to the Southern Ocean. Here we reconstruct dust-borne iron speciation over the last glacial cycle, showing that highly bioavailable iron(II) silicate minerals are a greater fraction of total iron reaching the Southern Ocean during glacial periods. The abundance of iron(II) silicates likely controls the bioavailable iron supply to the Southern Ocean and contributes to the previously observed increase in glacial productivity and CO2 drawdown. Changes in bioavailable dust-borne iron (Fe) supply to the iron-limited Southern Ocean may influence climate by modulating phytoplankton growth and CO2 fixation into organic matter that is exported to the deep ocean. The chemical form (speciation) of Fe impacts its bioavailability, and glacial weathering produces highly labile and bioavailable Fe minerals in modern dust sources. However, the speciation of dust-borne Fe reaching the iron-limited Southern Ocean on glacial−interglacial timescales is unknown, and its impact on the bioavailable iron supply over geologic time has not been quantified. Here we use X-ray absorption spectroscopy on subantarctic South Atlantic and South Pacific marine sediments to reconstruct dust-borne Fe speciation over the last glacial cycle, and determine the impact of glacial activity and glaciogenic dust sources on bioavailable Fe supply. We show that the Fe(II) content, as a percentage of total dust-borne Fe, increases from ∼5 to 10% in interglacial periods to ∼25 to 45% in glacial periods. Consequently, the highly bioavailable Fe(II) flux increases by a factor of ∼15 to 20 in glacial periods compared with the current interglacial, whereas the total Fe flux increases only by a factor of ∼3 to 5. The change in Fe speciation is dominated by primary Fe(II) silicates characteristic of glaciogenic dust. Our results suggest that glacial physical weathering increases the proportion of highly bioavailable Fe(II) in dust that reaches the subantarctic Southern Ocean in glacial periods, which represents a positive feedback between glacial activity and cold glacial temperatures.
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Duarte B, Cabrita MT, Vidal T, Pereira JL, Pacheco M, Pereira P, Canário J, Gonçalves FJM, Matos AR, Rosa R, Marques JC, Caçador I, Gameiro C. Phytoplankton community-level bio-optical assessment in a naturally mercury contaminated Antarctic ecosystem (Deception Island). MARINE ENVIRONMENTAL RESEARCH 2018; 140:412-421. [PMID: 30055834 DOI: 10.1016/j.marenvres.2018.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/16/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
Mercury naturally contaminated environments, like Deception Island (Antarctica), are field labs to study the physiological consequences of chronic Hg-exposure at the community level. Deception Island volcanic vents lead to a continuous chronic exposure of the phytoplanktonic communities to potentially toxic Hg concentrations. Comparing Hg-contaminated areas (Fumarolas Bay - FB, Gabriel de Castilla station - GdC station), no significant differences in chlorophyll a concentrations were detected, indicating that biomass production was not impaired by Hg-exposure despite the high Hg levels found in the cells. Moreover, the electron transport energy, responsible for energy production, also presented rather similar values in phytoplankton from both locations. Regarding FB communities, although the cells absorbed and trapped lower amounts of energy, the effect of Hg was not relevant in the photochemical work produced by the electronic transport chain. This might be due to the activation of alternative internal electron donors, as counteractive measure to the energy accumulated inside the cells. In fact, this alternative electron pathway, may have allowed FB communities to have similar electron transport energy fluxes without using respiration as photoprotective measure towards excessive energy. Hg-exposed cells also showed a shift from the energy flux towards the PS I (photosystem I), alleviating the excessive energy accumulation at the PS II (photosystem II) and preventing an oxidative burst. Our findings suggest a higher energy use efficiency in the communities exposed to volcanic Hg, which is not observable in cultured phytoplankton species grown under Hg exposure. This may constitute a metabolic adaptation, driven from chronic exposure allowing the maintenance of high levels of primary productivity under the assumingly unfavourable conditions of Deception Island.
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Affiliation(s)
- Bernardo Duarte
- Marine and Environmental Sciences Centre (MARE), Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal.
| | - Maria Teresa Cabrita
- Centro de Estudos Geográficos (CEG), Instituto de Geografia e Ordenamento do Território (IGOT), Universidade de Lisboa, Rua Branca Edmée Marques, 1600-276, Lisboa, Portugal; Instituto do Mar e da Atmosfera (IPMA), Rua Alfredo Magalhães Ramalho, 6, 1495-006, Algés, Portugal
| | - Tânia Vidal
- Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Joana Luísa Pereira
- Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Mário Pacheco
- Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Patrícia Pereira
- Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - João Canário
- Centro de Química Estrutural (CQE), Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1, 1049-001, Lisboa, Portugal
| | - Fernando J M Gonçalves
- Department of Biology & CESAM - Centre for Environmental and Marine Studies, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Ana Rita Matos
- Biosystems and Integrative Sciences Institute (BioISI), Plant Functional Genomics Group, Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal
| | - Rui Rosa
- Marine and Environmental Sciences Centre (MARE), Laboratório Marítimo da Guia, Faculdade de Ciências da Universidade de Lisboa, Avenida Nossa Senhora do Cabo 939, 2750-374, Cascais, Portugal
| | - João Carlos Marques
- Marine and Environmental Sciences Centre (MARE), c/o Departamento de Zoologia Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3000, Coimbra, Portugal
| | - Isabel Caçador
- Marine and Environmental Sciences Centre (MARE), Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal
| | - Carla Gameiro
- Marine and Environmental Sciences Centre (MARE), Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal; Instituto do Mar e da Atmosfera (IPMA), Rua Alfredo Magalhães Ramalho, 6, 1495-006, Algés, Portugal
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