| Autor: |
Jean-Paul Ambrosi, Sylvie Daumas, Laurent Eisenlohr, Lise Griffault, Laurent Trotignon, Michel de Combarieu, Jean-Eric Lartigue, Valérie Michaud |
| Rok vydání: |
2002 |
| Předmět: |
|
| Zdroj: |
Geochimica et Cosmochimica Acta. 66:2583-2601 |
| ISSN: |
0016-7037 |
| DOI: |
10.1016/s0016-7037(02)00851-7 |
| Popis: |
An experiment designed to study oxidizing perturbations in deep crystalline rock, a potential host for nuclear waste disposal, was conducted. This experiment simulated a fracture surface in contact with circulating groundwater, in which dissolved oxygen was injected periodically. Major physicochemical and biological parameters were monitored during this 1-yr experiment. Modeling of the results indicates that the kinetics of oxygen uptake may be represented by a simple steady-state rate law combining enzymatic catalysis (Monod) and a first-order rate law. Combined chemical and biological data demonstrate the coupling of organic/inorganic processes during the uptake of dissolved oxygen and the progressive return to reducing conditions. Timescales for these stages are discussed. Experimental results also suggest that iron-reducing bacteria, which are robust and well-adapted microorganisms, play a key role in these interfacial processes. These results show that an operational definition of the “redox buffering capacity” in a granitic medium cannot ignore the effect of bacteria and therefore the controls on bacterial substrates (organic carbon, H 2 , CH 4 , CO 2 ). |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect