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Tagliabue A, Buck KN, Sofen LE, Twining BS, Aumont O, Boyd PW, Caprara S, Homoky WB, Johnson R, König D, Ohnemus DC, Sohst B, Sedwick P. Authigenic mineral phases as a driver of the upper-ocean iron cycle. Nature 2023; 620:104-109. [PMID: 37532817 DOI: 10.1038/s41586-023-06210-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 05/12/2023] [Indexed: 08/04/2023]
Abstract
Iron is important in regulating the ocean carbon cycle1. Although several dissolved and particulate species participate in oceanic iron cycling, current understanding emphasizes the importance of complexation by organic ligands in stabilizing oceanic dissolved iron concentrations2-6. However, it is difficult to reconcile this view of ligands as a primary control on dissolved iron cycling with the observed size partitioning of dissolved iron species, inefficient dissolved iron regeneration at depth or the potential importance of authigenic iron phases in particulate iron observational datasets7-12. Here we present a new dissolved iron, ligand and particulate iron seasonal dataset from the Bermuda Atlantic Time-series Study (BATS) region. We find that upper-ocean dissolved iron dynamics were decoupled from those of ligands, which necessitates a process by which dissolved iron escapes ligand stabilization to generate a reservoir of authigenic iron particles that settle to depth. When this 'colloidal shunt' mechanism was implemented in a global-scale biogeochemical model, it reproduced both seasonal iron-cycle dynamics observations and independent global datasets when previous models failed13-15. Overall, we argue that the turnover of authigenic particulate iron phases must be considered alongside biological activity and ligands in controlling ocean-dissolved iron distributions and the coupling between dissolved and particulate iron pools.
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Affiliation(s)
| | - Kristen N Buck
- College of Marine Science, University of South Florida, St. Petersburg, FL, USA
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
| | - Laura E Sofen
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, USA
| | | | - Olivier Aumont
- LOCEAN, IRD-CNRS-Sorbonne Université-MNHN, IPSL, Paris, France
| | - Philip W Boyd
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia
| | - Salvatore Caprara
- College of Marine Science, University of South Florida, St. Petersburg, FL, USA
| | | | - Rod Johnson
- Bermuda Institute of Ocean Sciences, St. George's, Bermuda
| | - Daniela König
- School of Environmental Sciences, University of Liverpool, Liverpool, UK
- Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, Honolulu, HI, USA
| | - Daniel C Ohnemus
- Skidaway Institute of Oceanography, University of Georgia, Department of Marine Sciences, Savannah, GA, USA
| | - Bettina Sohst
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, USA
| | - Peter Sedwick
- Department of Ocean and Earth Sciences, Old Dominion University, Norfolk, VA, USA
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2
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Tagliabue A, Bowie AR, DeVries T, Ellwood MJ, Landing WM, Milne A, Ohnemus DC, Twining BS, Boyd PW. The interplay between regeneration and scavenging fluxes drives ocean iron cycling. Nat Commun 2019; 10:4960. [PMID: 31673108 PMCID: PMC6823497 DOI: 10.1038/s41467-019-12775-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 09/30/2019] [Indexed: 01/18/2023] Open
Abstract
Despite recent advances in observational data coverage, quantitative constraints on how different physical and biogeochemical processes shape dissolved iron distributions remain elusive, lowering confidence in future projections for iron-limited regions. Here we show that dissolved iron is cycled rapidly in Pacific mode and intermediate water and accumulates at a rate controlled by the strongly opposing fluxes of regeneration and scavenging. Combining new data sets within a watermass framework shows that the multidecadal dissolved iron accumulation is much lower than expected from a meta-analysis of iron regeneration fluxes. This mismatch can only be reconciled by invoking significant rates of iron removal to balance iron regeneration, which imply generation of authigenic particulate iron pools. Consequently, rapid internal cycling of iron, rather than its physical transport, is the main control on observed iron stocks within intermediate waters globally and upper ocean iron limitation will be strongly sensitive to subtle changes to the internal cycling balance. Iron is crucial for marine photosynthesis, but observational constraints on the magnitude of key iron cycle processes are lacking. Here the authors use a range of observational data sets to demonstrate that the balance between iron re-supply and removal in the subsurface controls upper ocean iron limitation.
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Affiliation(s)
| | - Andrew R Bowie
- Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobsart, TAS, Australia
| | - Timothy DeVries
- University of California Santa Barbara, Santa Barbara, CA, USA
| | - Michael J Ellwood
- Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
| | | | - Angela Milne
- Florida State University, Tallahassee, FL, USA.,University of Plymouth, Plymouth, UK
| | | | | | - Philip W Boyd
- Institute for Marine and Antarctic Studies and Antarctic Climate and Ecosystems CRC, University of Tasmania, Hobsart, TAS, Australia
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Brzezinski MA, Krause JW, Baines SB, Collier JL, Ohnemus DC, Twining BS. Patterns and regulation of silicon accumulation in Synechococcus spp. J Phycol 2017; 53:746-761. [PMID: 28457002 DOI: 10.1111/jpy.12545] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 04/18/2017] [Indexed: 06/07/2023]
Abstract
Six clones of the marine cyanobacterium Synechococcus, representing four major clades, were all found to contain significant amounts of silicon in culture. Growth rate was unaffected by silicic acid, Si(OH)4 , concentration between 1 and 120 μM suggesting that Synechococcus lacks an obligate need for silicon (Si). Strains contained two major pools of Si: an aqueous soluble and an aqueous insoluble pool. Soluble pool sizes correspond to estimated intracellular dissolved Si concentrations of 2-24 mM, which would be thermodynamically unstable implying the binding of intracellular soluble Si to organic ligands. The Si content of all clones was inversely related to growth rate and increased with higher [Si(OH)4 ] in the growth medium. Accumulation rates showed a unique bilinear response to increasing [Si(OH)4 ] from 1 to 500 μM with the rate of Si acquisition increasing abruptly between 80 and 100 μM Si(OH)4 . Although these linear responses imply some form of diffusion-mediated transport, Si uptake rates at low Si (~1 μM Si) were inhibited by orthophosphate, suggesting a role of phosphate transporters in Si acquisition. Theoretical calculations imply that observed Si acquisition rates are too rapid to be supported by lipid-solubility diffusion of Si through the plasmalemma; however, facilitated diffusion involving membrane protein channels may suffice. The data are used to construct a working model of the mechanisms governing the Si content and rate of Si acquisition in Synechococcus.
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Affiliation(s)
- Mark A Brzezinski
- Marine Science Institute and the Department of Ecology Evolution and Marine Biology, University of California, Santa Barbara, California, USA
| | - Jeffrey W Krause
- Dauphin Island Sea Lab, Dauphin Island, Alabama, USA
- Department of Marine Sciences, University of South Alabama, Mobile, Alabama, USA
| | - Stephen B Baines
- Department of Ecology and Evolution, Stony Brook University, Stony Brook, New York, USA
| | - Jackie L Collier
- School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, New York, USA
| | - Daniel C Ohnemus
- Bigelow Laboratory for Ocean Sciences, East Boothbay, Maine, USA
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4
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Anderson RF, Cheng H, Edwards RL, Fleisher MQ, Hayes CT, Huang KF, Kadko D, Lam PJ, Landing WM, Lao Y, Lu Y, Measures CI, Moran SB, Morton PL, Ohnemus DC, Robinson LF, Shelley RU. How well can we quantify dust deposition to the ocean? Philos Trans A Math Phys Eng Sci 2016; 374:rsta.2015.0285. [PMID: 29035251 DOI: 10.1098/rsta.2015.02852016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Accepted: 08/10/2016] [Indexed: 05/25/2023]
Abstract
Deposition of continental mineral aerosols (dust) in the Eastern Tropical North Atlantic Ocean, between the coast of Africa and the Mid-Atlantic Ridge, was estimated using several strategies based on the measurement of aerosols, trace metals dissolved in seawater, particulate material filtered from the water column, particles collected by sediment traps and sediments. Most of the data used in this synthesis involve samples collected during US GEOTRACES expeditions in 2010 and 2011, although some results from the literature are also used. Dust deposition generated by a global model serves as a reference against which the results from each observational strategy are compared. Observation-based dust fluxes disagree with one another by as much as two orders of magnitude, although most of the methods produce results that are consistent with the reference model to within a factor of 5. The large range of estimates indicates that further work is needed to reduce uncertainties associated with each method before it can be applied routinely to map dust deposition to the ocean. Calculated dust deposition using observational strategies thought to have the smallest uncertainties is lower than the reference model by a factor of 2-5, suggesting that the model may overestimate dust deposition in our study area.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.
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Affiliation(s)
- R F Anderson
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA
| | - H Cheng
- Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - R L Edwards
- Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - M Q Fleisher
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA
| | - C T Hayes
- Department of Marine Science, University of Southern Mississippi, Stennis Space Center, MS 39529, USA
| | - K-F Huang
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan, Republic of China
| | - D Kadko
- Applied Research Center, Florida International University, Miami, FL 33174, USA
| | - P J Lam
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - W M Landing
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Y Lao
- Department of Laboratory Services, Massachusetts Water Resources Authority, 190 Tafts Avenue, Winthrop, MA 02152, USA
| | - Y Lu
- Earth Observatory of Singapore, 50 Nanyang Avenue, Singapore 639798, Republic of Singapore
| | - C I Measures
- Department of Oceanography, University of Hawaii, Honolulu, HI 96822, USA
| | - S B Moran
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - P L Morton
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - D C Ohnemus
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME 04544, USA
| | - L F Robinson
- School of Earth Sciences, University of Bristol, Queens Road, Bristol BS8 1RJ, UK
| | - R U Shelley
- LEMAR/UMR CNRS 6539/IUEM, Technopôle Brest-Iroise, Place Nicolas Copernic, Plouzané 29280, France
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5
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Anderson RF, Cheng H, Edwards RL, Fleisher MQ, Hayes CT, Huang KF, Kadko D, Lam PJ, Landing WM, Lao Y, Lu Y, Measures CI, Moran SB, Morton PL, Ohnemus DC, Robinson LF, Shelley RU. How well can we quantify dust deposition to the ocean? Philos Trans A Math Phys Eng Sci 2016; 374:20150285. [PMID: 29035251 PMCID: PMC5069522 DOI: 10.1098/rsta.2015.0285] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 08/10/2016] [Indexed: 05/09/2023]
Abstract
Deposition of continental mineral aerosols (dust) in the Eastern Tropical North Atlantic Ocean, between the coast of Africa and the Mid-Atlantic Ridge, was estimated using several strategies based on the measurement of aerosols, trace metals dissolved in seawater, particulate material filtered from the water column, particles collected by sediment traps and sediments. Most of the data used in this synthesis involve samples collected during US GEOTRACES expeditions in 2010 and 2011, although some results from the literature are also used. Dust deposition generated by a global model serves as a reference against which the results from each observational strategy are compared. Observation-based dust fluxes disagree with one another by as much as two orders of magnitude, although most of the methods produce results that are consistent with the reference model to within a factor of 5. The large range of estimates indicates that further work is needed to reduce uncertainties associated with each method before it can be applied routinely to map dust deposition to the ocean. Calculated dust deposition using observational strategies thought to have the smallest uncertainties is lower than the reference model by a factor of 2-5, suggesting that the model may overestimate dust deposition in our study area.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'.
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Affiliation(s)
- R F Anderson
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA
- Department of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USA
| | - H Cheng
- Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - R L Edwards
- Department of Earth Sciences, University of Minnesota, Minneapolis, MN 55455, USA
| | - M Q Fleisher
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USA
| | - C T Hayes
- Department of Marine Science, University of Southern Mississippi, Stennis Space Center, MS 39529, USA
| | - K-F Huang
- Institute of Earth Sciences, Academia Sinica, Taipei, Taiwan, Republic of China
| | - D Kadko
- Applied Research Center, Florida International University, Miami, FL 33174, USA
| | - P J Lam
- Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - W M Landing
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Y Lao
- Department of Laboratory Services, Massachusetts Water Resources Authority, 190 Tafts Avenue, Winthrop, MA 02152, USA
| | - Y Lu
- Earth Observatory of Singapore, 50 Nanyang Avenue, Singapore 639798, Republic of Singapore
| | - C I Measures
- Department of Oceanography, University of Hawaii, Honolulu, HI 96822, USA
| | - S B Moran
- College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - P L Morton
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - D C Ohnemus
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME 04544, USA
| | - L F Robinson
- School of Earth Sciences, University of Bristol, Queens Road, Bristol BS8 1RJ, UK
| | - R U Shelley
- LEMAR/UMR CNRS 6539/IUEM, Technopôle Brest-Iroise, Place Nicolas Copernic, Plouzané 29280, France
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Lamborg CH, Hammerschmidt CR, Bowman KL, Swarr GJ, Munson KM, Ohnemus DC, Lam PJ, Heimbürger LE, Rijkenberg MJA, Saito MA. A global ocean inventory of anthropogenic mercury based on water column measurements. Nature 2014; 512:65-8. [DOI: 10.1038/nature13563] [Citation(s) in RCA: 331] [Impact Index Per Article: 33.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Accepted: 06/03/2014] [Indexed: 11/09/2022]
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