Earth Science Frontiers ›› 2020, Vol. 27 ›› Issue (5): 195-206.DOI: 10.13745/j.esf.sf.2020.5.53

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The evolutionary process of microbial community structure influenced by photoelectron from semiconducting minerals occurring at the “mineral membrane” on the Earth surface

REN Guiping1(), LU Anhuai2,*(), LI Yan2, WANG Changqiu2, DING Hongrui2,*()   

  1. 1. The Key Laboratory of Mineral Resources in Western China (Gansu Province), School of Earth Sciences, Lanzhou University, Lanzhou 730000, China
    2. The Key Laboratory of Orogenic Belts and Crustal Evolution/Beijing Key Laboratory of Mineral Environmental Function, School of Earth and Space Sciences, Peking University, Beijing 100871, China
  • Received:2020-04-25 Revised:2020-05-20 Online:2020-09-25 Published:2020-09-25
  • Contact: LU Anhuai,DING Hongrui

Abstract:

The interaction between minerals and microorganisms involved in the material recycling and energy transformation takes place on the earth's surface. In recently years, research on semiconducting minerals in natural environments has provided a new direction for the study of mineral-microbe interaction. It is one of the core scientific issues in the interdisciplinary study of geomicrobiology to reveal the electron transfer mechanism and its environmental effects on the “sunlight-semiconducting minerals-microorganisms” system. In this study, through examination of natural “mineral membrane” samples, we confirmed that the average photocurrents for karst, red soil and rock varnish samples were about 5.4, 3.4 and 3.2 μA/cm2, respectively, in the 1000 min long-term cycling experiments. The results demonstrated that the “mineral membrane” samples have good solar response characteristic, and iron/manganese oxide minerals play a key role in the response process. Moreover, based on our previous studies where we showed that the electroactive genera were enriched in “mineral membrane” and correlated positively with semiconducting mineral distribution, we successfully constructed a simulated photoelectron influencing bacterial community system in red soil. Twenty days later, the α diversity of bacterial community was significantly increased, and the bacterial community had an active response for simulating photoelectron. In addition, bacterial community presented directional evolutions at the electrode and in solution samples. The 16S rRNA sequencing analysis showed that Shewanella, Pseudomonas, Streptococcus, Lactobacillus, Acinetobacter and other electroactive genera were significantly enriched under the influence of simulated photoelectron. In conclusion, the results indirectly confirmed that photoelectron from semiconducting minerals in surface environments could regulate the structure of microbial community and promote enrichment of electroactive genera in the “mineral membrane” over time.

Key words: “mineral membrane”, on the earth surface, semiconducting minerals, photoelectron, electroactive genera

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