Meet the researcher scouring meteorite craters for ancient life

27 Nov 2019

Dr Henrik Drake, senior researcher, Linnaeus University. Image: Linnaeus University

Dr Henrik Drake of Linnaeus University is seeking answers to the evolution of life deep within the Earth itself.

Since completing his master’s at the University of Gothenburg in Sweden, Dr Henrik Drake has spent the past 10 years at Linnaeus University where he has been a senior researcher since 2018.

Some of his most recent research saw him and a team find evidence of microbial activity deep within Europe’s largest meteorite crater.

‘This has implications for evolution of life overall – especially in extreme environments – but also for astrobiology’

What inspired you to become a researcher?

I guess it all started when I did my master’s thesis at the University of Gothenburg, Sweden. My adviser took me to see the first retrieved deep drill core from the site investigation for a nuclear waste repository in Sweden.

In a sense, it was like stepping into an unseen world for me. This awakened a sleeping research personality, I guess, to decipher all of these unknowns. I was also intrigued to work with these unique cores and understand the significance of the whole nuclear waste repository project.

Can you tell us about the research you’re currently working on?

What I did not know when I started working with deep drill cores was that my main focus would shift from classic geology to geobiology. That journey started when I realised that the signatures and appearance of ancient life remains in the deep bedrock are both – more or less – unexplored. They also differ fundamentally from what we know from the surface biosphere.

The carbon isotope signatures that I analysed in tiny calcite crystals in fractures deep within the Swedish granitic basement are, to date, the most extreme reported from any environment on Earth.

These carbon isotope signatures are due to microbial methane consumption in the crust. The findings of this previously unknown methane sink was the start of a path I am now exploring. This involves ancient microbial methane production and consumption in fractures, as well as impact craters of the upper terrestrial crust.

In your opinion, why is your research important?

There are many important aspects. One is that I am exploring life at Earth’s extremes, in impact craters and other deep fracture networks in the crust.

This has implications for evolution of life overall – especially in extreme environments – but also for astrobiology. The methods we are developing to discover and characterise ancient life processes should be optimal for finding traces of deep, ancient life on other planets and what signatures to look for.

But such deep explorations are not planned within the near future. Another aspect I’m focusing on is deep methane cycling.

If methane is released into the atmosphere, it is a very potent greenhouse gas and more work is now needed to understand the significance of such contribution from deep biosphere microbial processes. The continental deep biosphere may add up to as much as between 10pc and 20pc of the biomass of Earth, so it is a vast, understudied, hard-to-reach environment.

What commercial applications do you foresee for your research?

Commercial aspects may involve energy efficient processes that we can learn from the deep biosphere, such as when it comes to natural gas production for energy. Or, on the other hand, as sinks for greenhouse gases.

There can also be novel degradation pathways for different wastes. Another aspect is finding unconventional fields of methane accumulation for potential commercial exploration.

What are some of the biggest challenges you face as a researcher in your field?

One challenge is to retrieve and get access to samples. Deep drilling is expensive, and we only have a couple of pinpricks so far to look into the deep underground.

Also, the drill core diameter of the boreholes limits the number of analyses that can be [carried out]. There are also contamination issues associated with drilling deep into a pristine environment.

Are there any common misconceptions about this area of research?

In the deep biosphere field, a lot of breakthrough research has been published in recent years, so many misconceptions come from those that haven’t kept up with the latest research.

This can, for instance, involve ideas that all methane found at depth comes from deep abiotic processes, which is certainly not the case. I tackle these misconceptions by providing scientifically sound evidence for my claims.

There are other crazy misconceptions that I get questions about from the public. It can be anything from that I find traces of extra-terrestrial life in the relatively young impact craters I study on Earth. Also, that the ancient microbial activity that we trace and date – from 400m years ago – are actually the same individual organisms that are alive today. I mean, that would be mind-blowing!

What are some of the areas of research you’d like to see tackled in the years ahead?

There is a huge gap in knowledge between the evolution of the surface biosphere compared to the less-studied deep biosphere. Regarding methane, I hope we can have an estimate of how much the deep continental biosphere contribute to the global budget.

Are you a researcher with an interesting project to share? Let us know by emailing with the subject line ‘Science Uncovered’.