Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experiments
Understanding hydrogen dynamics in soil organic matter is important to predict the fate of <sup>3</sup>H in terrestrial environments. One way to determine hydrogen fate and to point out processes is to examine the isotopic signature of the element in soil. However, the non-exchangeable h...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-12-01
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| Series: | Biogeosciences |
| Online Access: | http://www.biogeosciences.net/13/6587/2016/bg-13-6587-2016.pdf |
| _version_ | 1819243321295372288 |
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| author | A. Paul C. Hatté L. Pastor Y. Thiry F. Siclet J. Balesdent |
| author_facet | A. Paul C. Hatté L. Pastor Y. Thiry F. Siclet J. Balesdent |
| author_sort | A. Paul |
| collection | DOAJ |
| description | Understanding hydrogen dynamics in soil organic matter is
important to predict the fate of <sup>3</sup>H in terrestrial environments. One
way to determine hydrogen fate and to point out processes is to examine the
isotopic signature of the element in soil. However, the non-exchangeable
hydrogen isotopic signal in soil is complex and depends on the fate of
organic compounds and microbial biosyntheses that incorporate water-derived
hydrogen. To decipher this complex system and to understand the close link
between hydrogen and carbon cycles, we followed labeled hydrogen and labeled
carbon throughout near-natural soil incubations. We performed incubation
experiments with three labeling conditions: 1 – <sup>13</sup>C<sup>2</sup>H
double-labeled molecules in the presence of <sup>1</sup>H<sub>2</sub>O; 2 –
<sup>13</sup>C-labeled molecules in the presence of <sup>2</sup>H<sub>2</sub>O; 3 – no molecule
addition in the presence of <sup>2</sup>H<sub>2</sub>O. The preservation of
substrate-derived hydrogen after 1 year of incubation (ca. 5 % in most
cases) was lower than the preservation of substrate-derived carbon (30 %
in average). We highlighted that 70 % of the C–H bonds are broken during
the degradation of the molecule, which permits the exchange with water
hydrogen. Added molecules are used more for trophic resources. The isotopic
composition of the non-exchangeable hydrogen was mainly driven by the
incorporation of water hydrogen during microbial biosynthesis. It is
linearly correlated with the amount of carbon that is degraded in the soil.
The quantitative incorporation of water hydrogen in bulk material and lipids
demonstrates that non-exchangeable hydrogen exists in both organic and
mineral-bound forms. The proportion of the latter depends on soil type and
minerals. This experiment quantified the processes affecting the isotopic
composition of non-exchangeable hydrogen, and the results can be used to
predict the fate of tritium in the ecosystem or the water deuterium
signature in organic matter. |
| first_indexed | 2024-12-23T14:53:50Z |
| format | Article |
| id | doaj.art-07a9739c298b479f9139e9267748e162 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-23T14:53:50Z |
| publishDate | 2016-12-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-07a9739c298b479f9139e9267748e1622022-12-21T17:42:51ZengCopernicus PublicationsBiogeosciences1726-41701726-41892016-12-0113246587659810.5194/bg-13-6587-2016Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experimentsA. Paul0C. Hatté1L. Pastor2Y. Thiry3F. Siclet4J. Balesdent5Aix-Marseille Universite, CNRS, College de France, IRD, INRA, CEREGE UM34, 13545 Aix-en-Provence, FranceLaboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, UMR 8212 CEA-CNRS-UVSQ, Université Paris Saclay, 91198 Gif-sur-Yvette, FranceIFREMER/Centre de Brest, Département REM/EEP/LEP, CS 10070, 29280 Plouzané, FranceAndra, Research and Development Division, Parc de la Croix Blanche, 1/7 rue Jean Monnet, 92298 Châtenay-Malabry CEDEX, FranceEDF R&D, LNHE, 6 quai Watier, 78400 Chatou, FranceAix-Marseille Universite, CNRS, College de France, IRD, INRA, CEREGE UM34, 13545 Aix-en-Provence, FranceUnderstanding hydrogen dynamics in soil organic matter is important to predict the fate of <sup>3</sup>H in terrestrial environments. One way to determine hydrogen fate and to point out processes is to examine the isotopic signature of the element in soil. However, the non-exchangeable hydrogen isotopic signal in soil is complex and depends on the fate of organic compounds and microbial biosyntheses that incorporate water-derived hydrogen. To decipher this complex system and to understand the close link between hydrogen and carbon cycles, we followed labeled hydrogen and labeled carbon throughout near-natural soil incubations. We performed incubation experiments with three labeling conditions: 1 – <sup>13</sup>C<sup>2</sup>H double-labeled molecules in the presence of <sup>1</sup>H<sub>2</sub>O; 2 – <sup>13</sup>C-labeled molecules in the presence of <sup>2</sup>H<sub>2</sub>O; 3 – no molecule addition in the presence of <sup>2</sup>H<sub>2</sub>O. The preservation of substrate-derived hydrogen after 1 year of incubation (ca. 5 % in most cases) was lower than the preservation of substrate-derived carbon (30 % in average). We highlighted that 70 % of the C–H bonds are broken during the degradation of the molecule, which permits the exchange with water hydrogen. Added molecules are used more for trophic resources. The isotopic composition of the non-exchangeable hydrogen was mainly driven by the incorporation of water hydrogen during microbial biosynthesis. It is linearly correlated with the amount of carbon that is degraded in the soil. The quantitative incorporation of water hydrogen in bulk material and lipids demonstrates that non-exchangeable hydrogen exists in both organic and mineral-bound forms. The proportion of the latter depends on soil type and minerals. This experiment quantified the processes affecting the isotopic composition of non-exchangeable hydrogen, and the results can be used to predict the fate of tritium in the ecosystem or the water deuterium signature in organic matter.http://www.biogeosciences.net/13/6587/2016/bg-13-6587-2016.pdf |
| spellingShingle | A. Paul C. Hatté L. Pastor Y. Thiry F. Siclet J. Balesdent Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experiments Biogeosciences |
| title | Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experiments |
| title_full | Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experiments |
| title_fullStr | Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experiments |
| title_full_unstemmed | Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experiments |
| title_short | Hydrogen dynamics in soil organic matter as determined by <sup>13</sup>C and <sup>2</sup>H labeling experiments |
| title_sort | hydrogen dynamics in soil organic matter as determined by sup 13 sup c and sup 2 sup h labeling experiments |
| url | http://www.biogeosciences.net/13/6587/2016/bg-13-6587-2016.pdf |
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