The Role of Sulfuric Acid, Abiotic–Organic Acids, and Biotic Acids on Serpentinite Dissolution and Trace Metal Release
Organic acids produced by biota have been shown to accelerate the dissolution of minerals, possibly creating biosignatures in either reacting solutions or the solid materials. We tested aqueous alteration of serpentinite in three groups of solutions: inorganic acids, organic acids created through ab...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-02-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/14/3/256 |
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| author | Agnes R. Taylor Amanda Albright Olsen Elisabeth M. Hausrath Brian J. Olsen Dawn Cardace |
| author_facet | Agnes R. Taylor Amanda Albright Olsen Elisabeth M. Hausrath Brian J. Olsen Dawn Cardace |
| author_sort | Agnes R. Taylor |
| collection | DOAJ |
| description | Organic acids produced by biota have been shown to accelerate the dissolution of minerals, possibly creating biosignatures in either reacting solutions or the solid materials. We tested aqueous alteration of serpentinite in three groups of solutions: inorganic acids, organic acids created through abiotic processes (termed “abiotic–organics”), and organic acids created through biotic processes (termed “biotic acids”) over a range of temperatures relevant to conditions on Mars and Europa. A total of 48 batch reactor experiments were carried out at 0 °C, 22 °C, and 62 °C in 16 different acids at pH 2.6 over 28 days. Additional experiments were conducted in sulfuric acid solutions to assess aqueous alteration in sulfate-rich environments. These results show that biotic acids accelerate serpentinite dissolution compared to the control inorganic acid, whereas abiotic–organic acids have little or no effect. Sulfuric acid enhances serpentinite dissolution over nitric acid. Secondary precipitates found in the presence of biotic acids were consistently enhanced in Mn, Ti, and W. We propose that these preferentially released elements and secondary minerals may be potential biosignatures. We also show that the release of the rock-forming elements Mg and Si is correlated with stability constants for the metal–acid aqueous complex, providing a possible mechanistic interpretation of the observed results. |
| first_indexed | 2024-04-24T17:59:37Z |
| format | Article |
| id | doaj.art-a396a42c45b94c4f87614deca1b55426 |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-04-24T17:59:37Z |
| publishDate | 2024-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Minerals |
| spelling | doaj.art-a396a42c45b94c4f87614deca1b554262024-03-27T13:56:13ZengMDPI AGMinerals2075-163X2024-02-0114325610.3390/min14030256The Role of Sulfuric Acid, Abiotic–Organic Acids, and Biotic Acids on Serpentinite Dissolution and Trace Metal ReleaseAgnes R. Taylor0Amanda Albright Olsen1Elisabeth M. Hausrath2Brian J. Olsen3Dawn Cardace4School of Earth and Climate Science, University of Maine, Orono, ME 04469, USASchool of Earth and Climate Science, University of Maine, Orono, ME 04469, USADepartment of Geoscience, University of Nevada, Las Vegas, NV 89154, USASchool of Biology and Ecology, University of Maine, Orono, ME 04469, USADepartment of Geosciences, University of Rhode Island, Kingston, RI 02881, USAOrganic acids produced by biota have been shown to accelerate the dissolution of minerals, possibly creating biosignatures in either reacting solutions or the solid materials. We tested aqueous alteration of serpentinite in three groups of solutions: inorganic acids, organic acids created through abiotic processes (termed “abiotic–organics”), and organic acids created through biotic processes (termed “biotic acids”) over a range of temperatures relevant to conditions on Mars and Europa. A total of 48 batch reactor experiments were carried out at 0 °C, 22 °C, and 62 °C in 16 different acids at pH 2.6 over 28 days. Additional experiments were conducted in sulfuric acid solutions to assess aqueous alteration in sulfate-rich environments. These results show that biotic acids accelerate serpentinite dissolution compared to the control inorganic acid, whereas abiotic–organic acids have little or no effect. Sulfuric acid enhances serpentinite dissolution over nitric acid. Secondary precipitates found in the presence of biotic acids were consistently enhanced in Mn, Ti, and W. We propose that these preferentially released elements and secondary minerals may be potential biosignatures. We also show that the release of the rock-forming elements Mg and Si is correlated with stability constants for the metal–acid aqueous complex, providing a possible mechanistic interpretation of the observed results.https://www.mdpi.com/2075-163X/14/3/256serpentiniteweatheringbiosignaturesorganic acidsaqueous alteration |
| spellingShingle | Agnes R. Taylor Amanda Albright Olsen Elisabeth M. Hausrath Brian J. Olsen Dawn Cardace The Role of Sulfuric Acid, Abiotic–Organic Acids, and Biotic Acids on Serpentinite Dissolution and Trace Metal Release Minerals serpentinite weathering biosignatures organic acids aqueous alteration |
| title | The Role of Sulfuric Acid, Abiotic–Organic Acids, and Biotic Acids on Serpentinite Dissolution and Trace Metal Release |
| title_full | The Role of Sulfuric Acid, Abiotic–Organic Acids, and Biotic Acids on Serpentinite Dissolution and Trace Metal Release |
| title_fullStr | The Role of Sulfuric Acid, Abiotic–Organic Acids, and Biotic Acids on Serpentinite Dissolution and Trace Metal Release |
| title_full_unstemmed | The Role of Sulfuric Acid, Abiotic–Organic Acids, and Biotic Acids on Serpentinite Dissolution and Trace Metal Release |
| title_short | The Role of Sulfuric Acid, Abiotic–Organic Acids, and Biotic Acids on Serpentinite Dissolution and Trace Metal Release |
| title_sort | role of sulfuric acid abiotic organic acids and biotic acids on serpentinite dissolution and trace metal release |
| topic | serpentinite weathering biosignatures organic acids aqueous alteration |
| url | https://www.mdpi.com/2075-163X/14/3/256 |
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