Exploring nanoparticles in deep-sea hydrothermal vents

A black smoker as found in the Rainbow Hydrothermal field. Photo: Center for Marine Environmental Sciences (MARUM), University of Bremen (CC-BY 4.0)

Nanomaterials and nanoparticles are usually associated with high-tech industrial processes. But they have been a natural part of our planet from the very beginning, they show unique catalytic capabilities that may have (had) a major influence on biogeochemical processes. A joint project by Utrecht University and the Royal Institute for Sea Research (NIOZ) joint project will now step into uncharted territory and explore the world of deep-sea vent nanomaterials.

Iron nanoparticles found in hydrothermal vents could play a central role in carbon cycling. Image: Oliver Plümper (UU), Peter Kraal & Kristin Ungerhofer (NIOZ).

Nanomaterials seem like something that humanity developed over a long process of industrialisation and research. They have various industrial applications, from catalysts to coatings, drug delivery and many more. But nanomaterials were not invented by humanity, they have been critical natural components of the Earth since its formation and still play an important role in a plethora of geochemical and geological processes.

To this day, deep-sea hydrothermal vents, so-called black smokers, eject vast amounts of iron-containing nanoparticles into the ocean. Similar nanoparticles are known to catalyse the fixation of the greenhouse gas CO2 to hydrocarbons, a property that makes the hydrothermal particles a big potential player in the Earth’s carbon cycle and could unveil new ways for carbon fixation. Ultimately, such catalytic particles could have even played a crucial role in the emergence of life on Earth as hydrocarbons are one of the most central prerequisites for life as we know it.

Research excursion into uncharted territory

To understand the past, current and future role of hydrothermal iron nanoparticles on the Earth’s biogeochemical system, Utrecht University and NIOZ experts are going on a research excursion to the Mid-Atlantic Ridge in August 2022. We have built a truly exciting joint project between Utrecht University and NIOZ called I-NANO, short for iron nanoparticles, says excursion chief and geochemist Peter Kraal (NIOZ). We are stepping into uncharted territory here. The research crew, led by Kraal, mineral scientist of Utrecht University’s Structural Geology group Oliver Plümper (Utrecht University) and chemist Martina Preiner (NIOZ/Utrecht University), consists of geochemists, biologists, geologists and chemists.

The RV Pelagia is a 66m ocean-going vessel and the flagship of ocean research in the Netherlands. Photo: NIOZ

Aboard the flag ship of Dutch ocean research, NIOZ’ Pelagia, the scientists have eight days to collect samples at the hydrothermal vent fields Menez Gwen and Rainbow down to 2300 meters below sea surface and will perform newly developed experiments to investigate the catalytic properties of the particles. There are a lot of insights we can gain from these high-pressure CO2 fixation setups on board, explains Preiner. We are using fresh material that was never tested for its catalytic abilities like that before, we could find new catalysts, we could even find answers about the origin of organic molecules on an Earth before life.

Back on shore, Utrecht University’s cutting-edge imaging facilities and the biogeochemical laboratories at NIOZ’ ocean systems department will help the team to determine the origin and long-term fate of the nanoparticles and how they can influence the ocean’s biogeochemical balance. With our joint expertise we can look at almost anything, says Plümper.

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