Rapid Reactivation of Deep Subsurface Microbes in the Presence of C-1 Compounds

Microorganisms

Pauliina Rajala¹  Malin Bomberg¹  Riikka Kietäväinen²  Ilmo Kukkonen³  Lasse Ahonen²  Mari Nyyssönen¹  Merja Itävaara¹  Ludmila Chistoserdova⁴ 

[1] Technical Research Centre of Finland (VTT), Kemistintie 3/Tietotie 2, FI-02044, Espoo, Finland; E-Mails:;Geological Survey of Finland (GTK), P.O. Box 96, FI-02151, Espoo, Finland; E-Mails:;University of Helsinki, P.O. Box 33, University of Helsinki, FI-00014, Helsinki, Finland; E-Mail:Technical Research Centre of Finland (VTT), Kemistintie 3/Tietotie 2, FI-02044, Espoo, Finland;

关键词: C-1 carbon;    methanotrophy;    sulphate reduction;    nitrate reduction;    terrestrial deep biosphere;    microbial activity;   

DOI  :  10.3390/microorganisms3010017

来源: mdpi

【 摘 要 】

Microorganisms in the deep biosphere are believed to conduct little metabolic activity due to low nutrient availability in these environments. However, destructive penetration to long-isolated bedrock environments during construction of underground waste repositories can lead to increased nutrient availability and potentially affect the long-term stability of the repository systems, Here, we studied how microorganisms present in fracture fluid from a depth of 500 m in Outokumpu, Finland, respond to simple carbon compounds (C-1 compounds) in the presence or absence of sulphate as an electron acceptor. C-1 compounds such as methane and methanol are important intermediates in the deep subsurface carbon cycle, and electron acceptors such as sulphate are critical components of oxidation processes. Fracture fluid samples were incubated in vitro with either methane or methanol in the presence or absence of sulphate as an electron acceptor. Metabolic response was measured by staining the microbial cells with fluorescent dyes that indicate metabolic activity and transcriptional response with RT-qPCR. Our results show that deep subsurface microbes exist in dormant states but rapidly reactivate their transcription and respiration systems in the presence of C-1 substrates, particularly methane. Microbial activity was further enhanced by the addition of sulphate as an electron acceptor. Sulphate- and nitrate-reducing microbes were particularly responsive to the addition of C-1 compounds and sulphate. These taxa are common in deep biosphere environments and may be affected by conditions disturbed by bedrock intrusion, as from drilling and excavation for long-term storage of hazardous waste.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.