The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal system
<p>Chemoautotrophic Campylobacteria utilize the reductive tricarboxylic acid (rTCA) cycle for carbon uptake, a metabolic pathway that is more energy-efficient and discriminates less against <span class="inline-formula"><sup>13</sup></span>C than the Calvin–Ben...
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Copernicus Publications
2025-04-01
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| Series: | Biogeosciences |
| Online Access: | https://bg.copernicus.org/articles/22/1853/2025/bg-22-1853-2025.pdf |
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| author | J. M. Maak Y.-S. Lin E. Schefuß R. F. Aepfler R. F. Aepfler L.-L. Liu M. Elvert M. Elvert S. I. Bühring |
| author_facet | J. M. Maak Y.-S. Lin E. Schefuß R. F. Aepfler R. F. Aepfler L.-L. Liu M. Elvert M. Elvert S. I. Bühring |
| author_sort | J. M. Maak |
| collection | DOAJ |
| description | <p>Chemoautotrophic Campylobacteria utilize the reductive tricarboxylic acid (rTCA) cycle for carbon uptake, a metabolic pathway that is more energy-efficient and discriminates less against <span class="inline-formula"><sup>13</sup></span>C than the Calvin–Benson–Bassham cycle. Similar to other hydrothermal systems worldwide, Campylobacteria dominate the microbial community of the shallow-water hydrothermal system off Kueishantao (Taiwan). Compound-specific carbon stable isotope analyses of lipid-derived fatty acids were performed to understand the importance of rTCA and the transfer of fixed carbon to higher trophic levels in the vent area. Of these, C<span class="inline-formula"><sub>16:1<i>ω</i>7<i>c</i></sub></span>, C<span class="inline-formula"><sub>18:1<i>ω</i>7<i>c</i></sub></span>, and C<span class="inline-formula"><sub>18:1<i>ω</i>9<i>c</i></sub></span> fatty acids were strongly enriched in <span class="inline-formula"><sup>13</sup></span>C, indicating the activity of rTCA utilizing Campylobacteria. Isotopic fractionation was close to 0 ‰, likely caused by pH values as low as 2.88. Characteristic fatty acids were present not only in the vent fluids but also in adjacent sediments and water filters 20 m away from the vent orifice, albeit with decreasing abundance and diluted <span class="inline-formula"><sup>13</sup></span>C signal. Furthermore, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C analysis of fatty acids from the tissue of <i>Xenograpsus testudinatus</i>, a crab endemic to this particular vent system, identified the trophic transfer of chemosynthetically fixed carbon. This highlights the interrelationship between chemoautotrophic microbial activity and life opportunities of higher organisms under environmentally harsh conditions at shallow-water hydrothermal systems.</p> |
| format | Article |
| id | doaj-art-a5f3e02aba1e4a8396d4be5d2e711ea5 |
| institution | OA Journals |
| issn | 1726-4170 1726-4189 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Copernicus Publications |
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| series | Biogeosciences |
| spelling | doaj-art-a5f3e02aba1e4a8396d4be5d2e711ea52025-08-20T02:12:18ZengCopernicus PublicationsBiogeosciences1726-41701726-41892025-04-01221853186310.5194/bg-22-1853-2025The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal systemJ. M. Maak0Y.-S. Lin1E. Schefuß2R. F. Aepfler3R. F. Aepfler4L.-L. Liu5M. Elvert6M. Elvert7S. I. Bühring8MARUM – Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, GermanyDepartment of Oceanography, National Sun Yat-sen University, Kaohsiung, 80424, TaiwanMARUM – Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, GermanyMARUM – Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germanynow at: Logistics and research platforms, Alfred Wegener Institute (AWI), 27568 Bremerhaven, GermanyDepartment of Oceanography, National Sun Yat-sen University, Kaohsiung, 80424, TaiwanMARUM – Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, GermanyFaculty of Geosciences, University of Bremen, 28359 Bremen, GermanyMARUM – Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany<p>Chemoautotrophic Campylobacteria utilize the reductive tricarboxylic acid (rTCA) cycle for carbon uptake, a metabolic pathway that is more energy-efficient and discriminates less against <span class="inline-formula"><sup>13</sup></span>C than the Calvin–Benson–Bassham cycle. Similar to other hydrothermal systems worldwide, Campylobacteria dominate the microbial community of the shallow-water hydrothermal system off Kueishantao (Taiwan). Compound-specific carbon stable isotope analyses of lipid-derived fatty acids were performed to understand the importance of rTCA and the transfer of fixed carbon to higher trophic levels in the vent area. Of these, C<span class="inline-formula"><sub>16:1<i>ω</i>7<i>c</i></sub></span>, C<span class="inline-formula"><sub>18:1<i>ω</i>7<i>c</i></sub></span>, and C<span class="inline-formula"><sub>18:1<i>ω</i>9<i>c</i></sub></span> fatty acids were strongly enriched in <span class="inline-formula"><sup>13</sup></span>C, indicating the activity of rTCA utilizing Campylobacteria. Isotopic fractionation was close to 0 ‰, likely caused by pH values as low as 2.88. Characteristic fatty acids were present not only in the vent fluids but also in adjacent sediments and water filters 20 m away from the vent orifice, albeit with decreasing abundance and diluted <span class="inline-formula"><sup>13</sup></span>C signal. Furthermore, <span class="inline-formula"><i>δ</i><sup>13</sup></span>C analysis of fatty acids from the tissue of <i>Xenograpsus testudinatus</i>, a crab endemic to this particular vent system, identified the trophic transfer of chemosynthetically fixed carbon. This highlights the interrelationship between chemoautotrophic microbial activity and life opportunities of higher organisms under environmentally harsh conditions at shallow-water hydrothermal systems.</p>https://bg.copernicus.org/articles/22/1853/2025/bg-22-1853-2025.pdf |
| spellingShingle | J. M. Maak Y.-S. Lin E. Schefuß R. F. Aepfler R. F. Aepfler L.-L. Liu M. Elvert M. Elvert S. I. Bühring The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal system Biogeosciences |
| title | The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal system |
| title_full | The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal system |
| title_fullStr | The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal system |
| title_full_unstemmed | The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal system |
| title_short | The energy-efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the Kueishantao shallow-water hydrothermal system |
| title_sort | energy efficient reductive tricarboxylic acid cycle drives carbon uptake and transfer to higher trophic levels within the kueishantao shallow water hydrothermal system |
| url | https://bg.copernicus.org/articles/22/1853/2025/bg-22-1853-2025.pdf |
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