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Herndon E, Richardson J, Carrell AA, Pierce E, Weston D. Sulfur speciation in Sphagnum peat moss modified by mutualistic interactions with cyanobacteria. New Phytol 2024; 241:1998-2008. [PMID: 38135655 DOI: 10.1111/nph.19476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023]
Abstract
Peat moss (Sphagnum spp.) develops mutualistic interactions with cyanobacteria by providing carbohydrates and S compounds in exchange for N-rich compounds, potentially facilitating N inputs into peatlands. Here, we evaluate how colonization of Sphagnum angustifolium hyaline cells by Nostoc muscorum modifies S abundance and speciation at the scales of individual cells and across whole leaves. For the first time, S K-edge X-ray Absorption Spectroscopy was used to identify bulk and micron-scale S speciation across isolated cyanobacteria colonies, and in colonized and uncolonized leaves. Uncolonized leaves contained primarily reduced organic S and oxidized sulfonate- and sulfate-containing compounds. Increasing Nostoc colonization resulted in an enrichment of S and changes in speciation, with increases in sulfate relative to reduced S and sulfonate. At the scale of individual hyaline cells, colonized cells exhibited localized enrichment of reduced S surrounded by diffuse sulfonate, similar to observations of cyanobacteria colonies cultured in the absence of leaves. We infer that colonization stimulates plant S uptake and the production of sulfate-containing metabolites that are concentrated in stem tissues. Sulfate compounds that are produced in response to colonization become depleted in colonized cells where they may be converted into reduced S metabolites by cyanobacteria.
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Affiliation(s)
- Elizabeth Herndon
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | | | - Alyssa A Carrell
- Biological Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - Eric Pierce
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
| | - David Weston
- Biological Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
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2
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Li H, Reinhart B, Moller S, Herndon E. Effects of C/Mn Ratios on the Sorption and Oxidative Degradation of Small Organic Molecules on Mn-Oxides. Environ Sci Technol 2023; 57:741-750. [PMID: 36535081 DOI: 10.1021/acs.est.2c03633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Manganese (Mn) oxides have a high surface area and redox potential that facilitate sorption and/or oxidation of organic carbon (OC), but their role in regulating soil C storage is relatively unexplored. Small OC compounds with distinct structures were reacted with Mn(III/IV)-oxides to investigate the effects of OC/Mn molar ratios on Mn-OC interaction mechanisms. Dissolved and solid-phase OC and Mn were measured to quantify the OC sorption to and/or the redox reaction with Mn-oxides. Mineral transformation was evaluated using X-ray diffraction and X-ray absorption spectroscopy. Higher OC/Mn ratios resulted in higher sorption and/or redox transformation; however, interaction mechanisms differed at low or high OC/Mn ratios for some OC. Citrate, pyruvate, ascorbate, and catechol induced Mn-oxide dissolution. The average oxidation state of Mn in the solid phase did not change during the reaction with citrate, suggesting ligand-promoted mineral dissolution, but decreased significantly during reactions with the other compounds, suggesting reductive dissolution mechanisms. Phthalate primarily sorbed on Mn-oxides with no detectable formation of redox products. Mn-OC interactions led primarily to C loss through OC oxidation into inorganic C, except phthalate, which was predominantly immobilized in the solid phase. Together, these results provided detailed fundamental insights into reactions happening at organo-mineral interfaces in soils.
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Affiliation(s)
- Hui Li
- Department of Crop and Soil Sciences, North Carolina State University, Raleigh, North Carolina27695, United States
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
| | - Benjamin Reinhart
- X-ray Science Division, Argonne National Laboratory, Lemont, Illinois60439, United States
| | - Spencer Moller
- Department of Plant and Soil Sciences, University of Delaware, Newark, Delaware19716, United States
| | - Elizabeth Herndon
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee37831, United States
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3
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Patzner M, Kainz N, Lundin E, Barczok M, Smith C, Herndon E, Kinsman-Costello L, Fischer S, Straub D, Kleindienst S, Kappler A, Bryce C. Seasonal Fluctuations in Iron Cycling in Thawing Permafrost Peatlands. Environ Sci Technol 2022; 56:4620-4631. [PMID: 35290040 PMCID: PMC9097474 DOI: 10.1021/acs.est.1c06937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 03/01/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
In permafrost peatlands, up to 20% of total organic carbon (OC) is bound to reactive iron (Fe) minerals in the active layer overlying intact permafrost, potentially protecting OC from microbial degradation and transformation into greenhouse gases (GHG) such as CO2 and CH4. During the summer, shifts in runoff and soil moisture influence redox conditions and therefore the balance of Fe oxidation and reduction. Whether reactive iron minerals could act as a stable sink for carbon or whether they are continuously dissolved and reprecipitated during redox shifts remains unknown. We deployed bags of synthetic ferrihydrite (FH)-coated sand in the active layer along a permafrost thaw gradient in Stordalen mire (Abisko, Sweden) over the summer (June to September) to capture changes in redox conditions and quantify the formation and dissolution of reactive Fe(III) (oxyhydr)oxides. We found that the bags accumulated Fe(III) under constant oxic conditions in areas overlying intact permafrost over the full summer season. In contrast, in fully thawed areas, conditions were continuously anoxic, and by late summer, 50.4 ± 12.8% of the original Fe(III) (oxyhydr)oxides were lost via dissolution. Periodic redox shifts (from 0 to +300 mV) were observed over the summer season in the partially thawed areas. This resulted in the dissolution and loss of 47.2 ± 20.3% of initial Fe(III) (oxyhydr)oxides when conditions are wetter and more reduced, and new formation of Fe(III) minerals (33.7 ± 8.6% gain in comparison to initial Fe) in the late summer under more dry and oxic conditions, which also led to the sequestration of Fe-bound organic carbon. Our data suggest that there is seasonal turnover of iron minerals in partially thawed permafrost peatlands, but that a fraction of the Fe pool remains stable even under continuously anoxic conditions.
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Affiliation(s)
- Monique
S. Patzner
- Geomicrobiology,
Center for Applied Geosciences, University
of Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
| | - Nora Kainz
- Geomicrobiology,
Center for Applied Geosciences, University
of Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
| | - Erik Lundin
- Abisko
Scientific Research Station, Swedish Polar
Research Secretariat, Vetenskapens väg 38, SE-891
07 Abisko, Sweden
| | - Maximilian Barczok
- Department
of Geology, Kent State University, Kent, Ohio 44242, United States
| | - Chelsea Smith
- Department
of Biological Sciences, Kent State University, Kent, Ohio 44242, United States
| | - Elizabeth Herndon
- Environmental
Sciences Division, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830, United States
| | | | - Stefan Fischer
- Tuebingen
Structural Microscopy Core Facility, Center for Applied Geosciences, University Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
| | - Daniel Straub
- Microbial
Ecology, Center for Applied Geosciences, University Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
- Quantitative
Biology Center (QBiC), University Tuebingen, Auf der Morgenstelle 10, 72076 Tuebingen, Germany
| | - Sara Kleindienst
- Microbial
Ecology, Center for Applied Geosciences, University Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
| | - Andreas Kappler
- Geomicrobiology,
Center for Applied Geosciences, University
of Tuebingen, Schnarrenbergstrasse 94-96, 72076 Tuebingen, Germany
- Cluster
of Excellence: EXC 2124: Controlling Microbes to Fight Infection, 72074 Tübingen, Germany
| | - Casey Bryce
- School
of Earth Sciences, University of Bristol, Bristol BS8 1RJ, U.K.
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Eckert P, Johs A, Semrau JD, DiSpirito AA, Richardson J, Sarangi R, Herndon E, Gu B, Pierce EM. Spectroscopic and computational investigations of organometallic complexation of group 12 transition metals by methanobactins from Methylocystis sp. SB2. J Inorg Biochem 2021; 223:111496. [PMID: 34271330 PMCID: PMC10569158 DOI: 10.1016/j.jinorgbio.2021.111496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/17/2021] [Accepted: 05/26/2021] [Indexed: 12/30/2022]
Abstract
Methanotrophic bacteria catalyze the aerobic oxidation of methane to methanol using Cu-containing enzymes, thereby exerting a modulating influence on the global methane cycle. To facilitate the acquisition of Cu ions, some methanotrophic bacteria secrete small modified peptides known as "methanobactins," which strongly bind Cu and function as an extracellular Cu recruitment relay, analogous to siderophores and Fe. In addition to Cu, methanobactins form complexes with other late transition metals, including the Group 12 transition metals Zn, Cd, and Hg, although the interplay among solution-phase configurations, metal interactions, and the spectroscopic signatures of methanobactin-metal complexes remains ambiguous. In this study, the complexation of Zn, Cd, and Hg by methanobactin from Methylocystis sp. strain SB2 was studied using a combination of absorbance, fluorescence, extended x-ray absorption fine structure (EXAFS) spectroscopy, and time-dependent density functional theory (TD-DFT) calculations. We report changes in sample absorbance and fluorescence spectral dynamics, which occur on a wide range of experimental timescales and characterize a clear stoichiometric complexation dependence. Mercury L3-edge EXAFS and TD-DFT calculations suggest a linear model for HgS coordination, and TD-DFT suggests a tetrahedral model for Zn2+ and Cd2+. We observed an enhancement in the fluorescence of methanobactin upon interaction with transition metals and propose a mechanism of complexation-hindered isomerization drawing inspiration from the wild-type Green Fluorescent Protein active site. Collectively, our results represent the first combined computational and experimental spectroscopy study of methanobactins and shed new light on molecular interactions and dynamics that characterize complexes of methanobactins with Group 12 transition metals.
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Affiliation(s)
- Peter Eckert
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - Alexander Johs
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Jeremy D Semrau
- Civil & Environmental Engineering, The University of Michigan, Ann Arbor, MI 48109, USA
| | - Alan A DiSpirito
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
| | - Jocelyn Richardson
- Structural Molecular Biology Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94306, USA
| | - Ritimukta Sarangi
- Structural Molecular Biology Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94306, USA
| | - Elizabeth Herndon
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Baohua Gu
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA
| | - Eric M Pierce
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
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5
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Li H, Santos F, Butler K, Herndon E. A Critical Review on the Multiple Roles of Manganese in Stabilizing and Destabilizing Soil Organic Matter. Environ Sci Technol 2021; 55:12136-12152. [PMID: 34469151 DOI: 10.1021/acs.est.1c00299] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Manganese (Mn) is a biologically important and redox-active metal that may exert a poorly recognized control on carbon (C) cycling in terrestrial ecosystems. Manganese influences ecosystem C dynamics by mediating biochemical pathways that include photosynthesis, serving as a reactive intermediate in the breakdown of organic molecules, and binding and/or oxidizing organic molecules through organo-mineral associations. However, the potential for Mn to influence ecosystem C storage remains unresolved. Although substantial research has demonstrated the ability of Fe- and Al-oxides to stabilize organic matter, there is a scarcity of similar information regarding Mn-oxides. Furthermore, Mn-mediated reactions regulate important litter decomposition pathways, but these processes are poorly constrained across diverse ecosystems. Here, we discuss the ecological roles of Mn in terrestrial environments and synthesize existing knowledge on the multiple pathways by which biogeochemical Mn and C cycling intersect. We demonstrate that Mn has a high potential to degrade organic molecules through abiotic and microbially mediated oxidation and to stabilize organic molecules, at least temporarily, through organo-mineral associations. We outline research priorities needed to advance understanding of Mn-C interactions, highlighting knowledge gaps that may address key uncertainties in soil C predictions.
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Affiliation(s)
- Hui Li
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Fernanda Santos
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Kristen Butler
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Earth and Planetary Sciences, College of Arts & Sciences, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Elizabeth Herndon
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Earth and Planetary Sciences, College of Arts & Sciences, University of Tennessee, Knoxville, Tennessee 37996, United States
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6
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Herndon E, Kinsman-Costello L, Di Domenico N, Duroe K, Barczok M, Smith C, Wullschleger SD. Iron and iron-bound phosphate accumulate in surface soils of ice-wedge polygons in arctic tundra. Environ Sci Process Impacts 2020; 22:1475-1490. [PMID: 32475995 DOI: 10.1039/d0em00142b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Phosphorus (P) is a limiting or co-limiting nutrient to plants and microorganisms in diverse ecosystems that include the arctic tundra. Certain soil minerals can adsorb or co-precipitate with phosphate, and this mineral-bound P provides a potentially large P reservoir in soils. Iron (Fe) oxyhydroxides have a high capacity to adsorb phosphate; however, the ability of Fe oxyhydroxides to adsorb phosphate and limit P bioavailability in organic tundra soils is not known. Here, we examined the depth distribution of soil Fe and P species in the active layer (<30 cm) of low-centered and high-centered ice-wedge polygons at the Barrow Environmental Observatory on the Alaska North Slope. Soil reservoirs of Fe and P in bulk horizons and in narrower depth increments were characterized using sequential chemical extractions and synchrotron-based X-ray absorption spectroscopy (XAS). Organic horizons across all polygon features (e.g., trough, ridge, and center) were enriched in extractable Fe and P relative to mineral horizons. Soil Fe was dominated by organic-bound Fe and short-range ordered Fe oxyhydroxides, while soil P was primarily associated with oxides and organic matter in organic horizons but apatite and/or calcareous minerals in mineral horizons. Iron oxyhydroxides and Fe-bound inorganic P (Pi) were most enriched at the soil surface and decreased gradually with depth, and Fe-bound Pi was >4× greater than water-soluble Pi. These results demonstrate that Fe-bound Pi is a large and ecologically important reservoir of phosphate. We contend that Fe oxyhydroxides and other minerals may regulate Pi solubility under fluctuating redox conditions in organic surface soils on the arctic tundra.
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Affiliation(s)
- Elizabeth Herndon
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA. and Department of Geology, Kent State University, Kent, OH, USA
| | | | | | - Kiersten Duroe
- Department of Geology, Kent State University, Kent, OH, USA
| | | | - Chelsea Smith
- Department of Biological Sciences, Kent State University, Kent, OH, USA
| | - Stan D Wullschleger
- Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA.
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Brantley SL, Megonigal JP, Scatena FN, Balogh-Brunstad Z, Barnes RT, Bruns MA, Van Cappellen P, Dontsova K, Hartnett HE, Hartshorn AS, Heimsath A, Herndon E, Jin L, Keller CK, Leake JR, McDowell WH, Meinzer FC, Mozdzer TJ, Petsch S, Pett-Ridge J, Pregitzer KS, Raymond PA, Riebe CS, Shumaker K, Sutton-Grier A, Walter R, Yoo K. Twelve testable hypotheses on the geobiology of weathering. Geobiology 2011; 9:140-165. [PMID: 21231992 DOI: 10.1111/j.1472-4669.2010.00264.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Critical Zone (CZ) research investigates the chemical, physical, and biological processes that modulate the Earth's surface. Here, we advance 12 hypotheses that must be tested to improve our understanding of the CZ: (1) Solar-to-chemical conversion of energy by plants regulates flows of carbon, water, and nutrients through plant-microbe soil networks, thereby controlling the location and extent of biological weathering. (2) Biological stoichiometry drives changes in mineral stoichiometry and distribution through weathering. (3) On landscapes experiencing little erosion, biology drives weathering during initial succession, whereas weathering drives biology over the long term. (4) In eroding landscapes, weathering-front advance at depth is coupled to surface denudation via biotic processes. (5) Biology shapes the topography of the Critical Zone. (6) The impact of climate forcing on denudation rates in natural systems can be predicted from models incorporating biogeochemical reaction rates and geomorphological transport laws. (7) Rising global temperatures will increase carbon losses from the Critical Zone. (8) Rising atmospheric P(CO2) will increase rates and extents of mineral weathering in soils. (9) Riverine solute fluxes will respond to changes in climate primarily due to changes in water fluxes and secondarily through changes in biologically mediated weathering. (10) Land use change will impact Critical Zone processes and exports more than climate change. (11) In many severely altered settings, restoration of hydrological processes is possible in decades or less, whereas restoration of biodiversity and biogeochemical processes requires longer timescales. (12) Biogeochemical properties impart thresholds or tipping points beyond which rapid and irreversible losses of ecosystem health, function, and services can occur.
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Affiliation(s)
- S L Brantley
- Earth and Environmental Systems Institute, Pennsylvania State University, University Park, PA, USA.
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Beltsos A, Herndon E, Jasulaitis L, Lederer K, Byers M, Uhler M. Comparison of luteal phase support with endometrin vs. progesterone in oil in donor oocyte cycles. Fertil Steril 2009. [DOI: 10.1016/j.fertnstert.2009.07.296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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