GFZ German research centre for geo sciences

Active fault zones as „hot spots“ for microbial life in the deep subsurface?

Microbial life in the deep subsurface has to date been subject to little research and is still largely not understood. Yesterday, a drill project started in the Cheb Basin in Czech Republic that aims at shedding light on the interaction between microbes, rock, and fluids of the deep subsurface. As Principle Investigator Dr. Mashal Alawi, GFZ section Geomicrobiology, is responsible for planning and execution of the drill-project.

 

13.04.2016: Microbial life in the deep subsurface has to date been subject to little research and is still largely not understood. Yesterday, a drill project started in the Cheb Basin in Czech Republic that aims at shedding light on the interaction between microbes, rock, and fluids of the deep subsurface. As Principle Investigator Dr. Mashal Alawi, GFZ section Geomicrobiology, is responsible for planning and execution of the drill-project.

In focus of the project is the examination of the geo-bio-interaction. Microbial activity in the deep surface is affected by the substrate and gas available. Their availability depends on the seismic activity. The activity of the microbes in turn impacts the chemistry of fluids and gas chemistry in the subsurface.

The project entitled „Microbial processes in the deep biosphere of the CO2-dominated active fault zone in NW Bohemia“ is funded by the German Research Foundation DFG. It is planned as a pilot study to the comprehensive ICDP(International Continental Drilling) project „Drilling the Eger Rift: Magmatic fluids driving earthquake swarms and the deep biosphere“.

Drilling into an active CO2 conduit

The Cheb Basin within the Eger Rift region is a small intercontinental sediment basin in the center of the intersection of the rift. It is located within an active fault zone. The region is known as a seismically active continental earthquake swarm region without active volcanism. Earthquake swarms are a certain form of earthquakes series with the same intensity and duration of several days up to one year.

The seismic activity is a result of the upward intrusion of magma from the Earth’s interior. It also triggers high rates of CO2 degassing from the subsurface. The drilling aims at identifying to what extent the seismic activity and therewith the degassing affects the microbial activity. This drilling is done into an active CO2 conduit which makes it technically very demanding.

The drilling was prepared by the installation of cemented stand pipes for the first 15 meters of the subsurface. This secures the stability of the actual drilling. Starting today, a continuous core is drilled down to a depth of 100 meters. For an on-site sampling of the core and first analysis a GFZ container laboratory (BUGLab) is in service.

„Hot spots“ of microbial activity

The aim of the drill is the investigation of the impact of CO2-degassing on the depth distribution and composition of the microbial community and the analysis of its carbon and energy sources. Dr. Mashal Alawi: “We hypothesize that in active fault zones like we find one in the Cheb Basin microbial activity is significantly accelerated. This is due to an intensified mass exchange, compared to other continental Deep Biosphere ecosystems.” The drilling will reveal if active fault zones are „hot spots‟ of microbial life in the deep subsurface. (ak)

>> More information may be found in the GFZ-Journal System Earth (2015) volume 5, issue 1 „Mikrobiologische Prozesse in CO2-Aufstiegskanälen" [German only!]

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