Lasse Ahonen

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We report the first investigation of a deep subpermafrost microbial ecosystem, a terrestrial analog for the Martian subsurface. Our multidisciplinary team analyzed fracture water collected at 890 and 1,130 m depths beneath a 540-m-thick permafrost layer at the Lupin Au mine (Nunavut, Canada). 14C, 3H, and noble gas isotope analyses suggest that the(More)
This paper demonstrates the first microbiological sampling of the Outokumpu deep borehole (2516 m deep) aiming at characterizing the bacterial community composition and diversity of sulphate-reducing bacteria (SRB) in Finnish crystalline bedrock aquifers. Sampling was performed using a 1500-m-long pressure-tight tube that provided 15 subsamples, each(More)
Microbial life in the nutrient-limited and low-permeability continental crystalline crust is abundant but remains relatively unexplored. Using high-throughput sequencing to assess the 16S rRNA gene diversity, we found diverse bacterial and archaeal communities along a 2516-m-deep drill hole in continental crystalline crust in Outokumpu, Finland. These(More)
Deep fracture zones in Finnish crystalline bedrock have been isolated for long, the oldest fluids being tens of millions of years old. To accurately measure the native microbial diversity in fracture-zone fluids, water samples were obtained by isolating the borehole fraction spanning a deep subsurface aquifer fracture zone with inflatable packers (500 and(More)
A cheese dairy and its whey manufacturing line were examined for Bacillus cereus. Colonies typical of B. cereus were detected in 120 (17%) samples out of 720 analysed. Only 3% of the sampled raw milk contained B. cereus ( > or = 10 cfu ml(-1)) whereas in evaporated whey concentrate B. cereus was present in 76% of the samples. Nitrate reductase negative and(More)
The deep subsurface hosts diverse life, but the mechanisms that sustain this diversity remain elusive. Here, we studied microbial communities involved in carbon cycling in deep, dark biosphere and identified anaerobic microbial energy production mechanisms from groundwater of Fennoscandian crystalline bedrock sampled from a deep drill hole in Outokumpu,(More)
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(More)
Pyhäsalmi mine in central Finland provides an excellent opportunity to study microbial and geochemical processes in a deep subsurface crystalline rock environment through near-vertical drill holes that reach to a depth of more than two kilometers below the surface. However, microbial sampling was challenging in this high-pressure environment. Nucleic acid(More)
Acetate plays a key role as electron donor and acceptor and serves as carbon source in oligotrophic deep subsurface environments. It can be produced from inorganic carbon by acetogenic microbes or through breakdown of more complex organic matter. Acetate is an important molecule for sulfate reducers that are substantially present in several deep bedrock(More)
The deep terrestrial biosphere is an intriguing research field linking to astrobiology and evolution of life on early Earth (Grosch and Hazen, 2015). Living in the deep, dark, anoxic, oligotrophic, saline, highly pressurized and often hot subsurface requires some striking characteristics of the inhabitants (Kieft, 2016). We still know only little about the(More)