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Award for research into the deep biosphere

May 31, 2024
In the spotlight of the U.S. deep-sea submersible ALVIN, a small reddish-brown vent massif can be seen on the seafloor of the Guaymas Basin. This formation is surrounded by abundant hydrothermally heated oil-rich sediments covered by white and orange bacterial mats. The core from which the Candidatus Alkanophaga archaea ultimately originated was collected by the team of the manned deep-sea submersible. Photo: Woods Hole Oceanographic Institution.
In the spotlight of the U.S. deep-sea submersible ALVIN, a small reddish-brown vent massif can be seen on the seafloor of the Guaymas Basin. This formation is surrounded by abundant hydrothermally heated oil-rich sediments covered by white and orange bacterial mats. The core from which the Candidatus Alkanophaga archaea ultimately originated was collected by the team of the manned deep-sea submersible. Photo: Woods Hole Oceanographic Institution.

How and what do microorganisms in deep-sea soils live on? How do their metabolic cycles work, and how do the individual members of these buried communities interact? A team of researchers at MARUM – Center for Marine Environmental Sciences at the University of Bremen and the Max Planck Institute for Marine Microbiology Bremen has been working on the questions. For the first time, they were able to demonstrate in laboratory cultures how petroleum components are broken down by archaea – a group of microorganisms. The publication in the journal Nature Microbiology has now been selected by the International Center for Deep Life Investigation as one of the five best studies in 2023 for research into the deep biosphere.

 

The work “identifies a new set of organisms that may be responsible for oil degradation in in high-temperature wells” states the jury. For the first time, the team of authors had enriched anaerobic archaea that oxidize petroleum alkane chains of 5-14 carbons, using a newly discovered enzyme, an alkyl-CoM reductase (Acrs).

First author Hannah Zehnle and her co-authors from the Max Planck Institute for Marine Microbiology, the MARUM – Center for Marine Environmental Sciences and the Department of Geosciences at the University of Bremen used sediment from the 2,000-meter-deep Guaymas Basin in the Gulf of California. Due to geological peculiarities, high temperatures, liquid petroleum components and anaerobic conditions are found here at shallow sediment depths, which would otherwise only be found in deep-seated oil reservoirs and would therefore be much more difficult for researchers to reach.

In the Bremen laboratory, the researchers prepared cultures with liquid alkanes and allowed them to grow without oxygen, i.e. anaerobically, at high temperatures (70 degrees Celsius). The study shows that the enzymes involved can also act in completely different metabolic pathways and on liquid and therefore toxic hydrocarbons.

Colleagues from the Department of Systems Biology, National Center for Biotechnology-CSIC Madrid (Spain), the Max Planck Institute for Multidisciplinary Sciences Göttingen and the Department of Earth, Ocean and Environmental Sciences, University of North Carolina (USA), were also involved.

From proposed top publications of 2023, a committee has selected five articles that make the most remarkable contributions to deep biosphere research. Every year, the International Center for Deep Life Investigation (IC-DLI) honors scientific publications that are groundbreaking for research on and in the deep biosphere. The awards are intended to recognize significant scientific contributions and outstanding young scientists, according to the IC-DLI. The aim is to promote contributions to deep life research and support the next generation of researchers in this field.

More information

Press release about the publication by MPI and MARUM

Original publication