Iodide uptake by forest soils is principally related to the activity of extracellular oxidases
129I is a nuclear fission decay product of concern because of its long half-life (16 Ma) and propensity to bioaccumulate. Microorganisms impact iodine mobility in soil systems by promoting iodination (covalent binding) of soil organic matter through processes that are not fully understood. Here, we...
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| Format: | Article |
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Frontiers Media S.A.
2023-03-01
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| Series: | Frontiers in Chemistry |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fchem.2023.1105641/full |
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| author | Russell M. Grandbois Peter H. Santschi Chen Xu Joshua M. Mitchell Daniel I. Kaplan Chris M. Yeager |
| author_facet | Russell M. Grandbois Peter H. Santschi Chen Xu Joshua M. Mitchell Daniel I. Kaplan Chris M. Yeager |
| author_sort | Russell M. Grandbois |
| collection | DOAJ |
| description | 129I is a nuclear fission decay product of concern because of its long half-life (16 Ma) and propensity to bioaccumulate. Microorganisms impact iodine mobility in soil systems by promoting iodination (covalent binding) of soil organic matter through processes that are not fully understood. Here, we examined iodide uptake by soils collected at two depths (0–10 and 10–20 cm) from 5 deciduous and coniferous forests in Japan and the United States. Autoclaved soils, and soils amended with an enzyme inhibitor (sodium azide) or an antibacterial agent (bronopol), bound significantly less 125I tracer (93%, 81%, 61% decrease, respectively) than the untreated control soils, confirming a microbial role in soil iodide uptake. Correlation analyses identified the strongest significant correlation between 125I uptake and three explanatory variables, actinobacteria soil biomass (p = 6.04E-04, 1.35E-02 for Kendall-Tau and regression analysis, respectively), soil nitrogen content (p = 4.86E-04, 4.24E-03), and soil oxidase enzyme activity at pH 7.0 using the substrate L-DOPA (p = 2.83E-03, 4.33E-04) and at pH 5.5 using the ABTS (p = 5.09E-03, 3.14E-03). Together, the results suggest that extracellular oxidases, primarily of bacterial origin, are the primary catalyst for soil iodination in aerobic, surface soils of deciduous and coniferous forests, and that soil N content may be indicative of the availability of binding sites for reactive iodine species. |
| first_indexed | 2024-04-10T06:18:16Z |
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| id | doaj.art-3baf66023d0244eea847b8b9e97be32a |
| institution | Directory Open Access Journal |
| issn | 2296-2646 |
| language | English |
| last_indexed | 2024-04-10T06:18:16Z |
| publishDate | 2023-03-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Chemistry |
| spelling | doaj.art-3baf66023d0244eea847b8b9e97be32a2023-03-02T05:22:57ZengFrontiers Media S.A.Frontiers in Chemistry2296-26462023-03-011110.3389/fchem.2023.11056411105641Iodide uptake by forest soils is principally related to the activity of extracellular oxidasesRussell M. Grandbois0Peter H. Santschi1Chen Xu2Joshua M. Mitchell3Daniel I. Kaplan4Chris M. Yeager5Laboratory for Environmental and Oceanographic Research, Department of Marine Sciences, Texas A&M University—Galveston, Galveston, TX, United StatesLaboratory for Environmental and Oceanographic Research, Department of Marine Sciences, Texas A&M University—Galveston, Galveston, TX, United StatesLaboratory for Environmental and Oceanographic Research, Department of Marine Sciences, Texas A&M University—Galveston, Galveston, TX, United StatesChemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM, United StatesSavannah River Ecology Laboratory, University of Georgia, Aiken, SC, United StatesChemical Diagnostics and Engineering, Los Alamos National Laboratory, Los Alamos, NM, United States129I is a nuclear fission decay product of concern because of its long half-life (16 Ma) and propensity to bioaccumulate. Microorganisms impact iodine mobility in soil systems by promoting iodination (covalent binding) of soil organic matter through processes that are not fully understood. Here, we examined iodide uptake by soils collected at two depths (0–10 and 10–20 cm) from 5 deciduous and coniferous forests in Japan and the United States. Autoclaved soils, and soils amended with an enzyme inhibitor (sodium azide) or an antibacterial agent (bronopol), bound significantly less 125I tracer (93%, 81%, 61% decrease, respectively) than the untreated control soils, confirming a microbial role in soil iodide uptake. Correlation analyses identified the strongest significant correlation between 125I uptake and three explanatory variables, actinobacteria soil biomass (p = 6.04E-04, 1.35E-02 for Kendall-Tau and regression analysis, respectively), soil nitrogen content (p = 4.86E-04, 4.24E-03), and soil oxidase enzyme activity at pH 7.0 using the substrate L-DOPA (p = 2.83E-03, 4.33E-04) and at pH 5.5 using the ABTS (p = 5.09E-03, 3.14E-03). Together, the results suggest that extracellular oxidases, primarily of bacterial origin, are the primary catalyst for soil iodination in aerobic, surface soils of deciduous and coniferous forests, and that soil N content may be indicative of the availability of binding sites for reactive iodine species.https://www.frontiersin.org/articles/10.3389/fchem.2023.1105641/fulliodideoxidaseforest soiliodinationlaccaseradioiodine |
| spellingShingle | Russell M. Grandbois Peter H. Santschi Chen Xu Joshua M. Mitchell Daniel I. Kaplan Chris M. Yeager Iodide uptake by forest soils is principally related to the activity of extracellular oxidases Frontiers in Chemistry iodide oxidase forest soil iodination laccase radioiodine |
| title | Iodide uptake by forest soils is principally related to the activity of extracellular oxidases |
| title_full | Iodide uptake by forest soils is principally related to the activity of extracellular oxidases |
| title_fullStr | Iodide uptake by forest soils is principally related to the activity of extracellular oxidases |
| title_full_unstemmed | Iodide uptake by forest soils is principally related to the activity of extracellular oxidases |
| title_short | Iodide uptake by forest soils is principally related to the activity of extracellular oxidases |
| title_sort | iodide uptake by forest soils is principally related to the activity of extracellular oxidases |
| topic | iodide oxidase forest soil iodination laccase radioiodine |
| url | https://www.frontiersin.org/articles/10.3389/fchem.2023.1105641/full |
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