Experimental Research on Microbial Degradation of Organic Matter Adsorbed in Smectite Internal Surface Area in the Interlayer of the Structure
详细信息
- 责任者：Yu BingSong(Geomicrobiology Laboratory ; State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Dong HaiLiang
- 刊名：Acta Petrologica Sinica
- 出版年：2012
- 卷期：28(3)
- 页码：p.949-960
- issnNo：ISSN1000-0569
- isbnNo：CN11-1922/P
摘要
It has been recognized that the adsorption of organic matter(OM)into smectite internal surface area in the interlayer of structure is one of the most important preservation mechanisms in recent years, whereas there is no experimental data to indicate whether and to what extent the microbes can degrade the OM adsorbed in the smectite internal surface area. In order to understand the contribution of the adsorption of OM in the internal surface area to preservation of OM in the burying process of the sediments, the microbial degradation to OM adsorbed in the internal surface area of smectite has been researched through experiments with the different kinds of microbes. Cysteine and toluene are selected as the experimental OM. The former is an important amino acid for growing of life, and the later ubiquitously occurs in the soils and sediments and can be degraded by many kinds of bacteria. Pseudomonas putida and Shewanella putrefaciens CN32 are common microbes in the marine and lacustrine sediments. The former has strong ability to degrade the OM, and the later is the Fe-deoxidized bacterium, which can deoxidize the Fe(III)in the crystal structure of smectite into Fe(II)in the anaerobic metabolism. Through the degradation experiments of different kinds of OM adsorbed in the internal surface area of smectite with the different kinds of microbes, some conclusions can be got from the results. The degradation process of microbes to OM is through the secretion of organic acid or destroying the crystal structure to release the adsorbed OM. The experiment results indicate that the degradation of OM adsorbed in the internal surface area through the secretion of organic acid from microbes is little, and the internal adsorption of OM in the interlayer structure is effective for the preservation of OM in the aerobic or anaerobic environments. Shewanella putrefaciens CN32 metabolizes through the deoxidization of Fe(III)in the anaerobic environment. It can destroy crystal structure of smectite to some extent and release some adsorbed OM. So the Fe-deoxidized bacteria can affect the preservation of OM in some extent, whereas due to the limited effect on crystal structure caused by microbes, the degradation ability to OM adsorbed in the internal surface area from Fe-deoxidized bacteria is not predominant yet. Character of OM is also a factor influencing on microbial degradation of OM. Cysteine is propitious to develop for microbes, and may promote deoxidization of Fe(III), by contraries, toluene is poisonous to microbes and it obviously restrain the deoxidization of Fe(III). Thus it can be seen that the adsorption of OM in smectite internal surface area in interlayer of structure can effectively prevent degradation from microbes and is an important preservation mode of OM in sediments.