20-EPN2-099: Bioaerosol generation at geothermal systems: Implications for the detection of biosignatures in cryovolcanic plumes at the ocean worlds
Visit by Mark Fox-Powell and Claire Batty, Open University (UK) to TA1 – Iceland Field Sites, MATIS
Dates of visit: 27 July – 09 August 2022
The aim of our project was to capture and study microscopic aerosols ejected from bubbling or geysering geothermal springs in Iceland. Our primary motivation was to understand the potential for biosignatures to become entrained within cryovolcanic plumes at icy moons, such as Saturn’s moon Enceladus, where similar bubbling of hydrothermal gases is thought to drive the formation of aerosols that are then accelerated into space. Fieldwork was conducted at geothermal systems in Iceland in July and August 2022 by a team from the Open University (UK).
We focused our aerosol sampling efforts on two locations that exhibit contrasting aerosolisation regimes: Olkelduhals hot springs, Hverageroi, which exhibit constant, moderate bubbling of geothermal gases, and Strokkur, Geysir, which experiences regular energetic geyser eruptions. Our aerosol flux monitoring showed that geothermal springs are prolific local sources of aerosols, producing fluxes orders of magnitude above background levels. We also found that aerosol production is tightly controlled by bubbling and/or eruption activity.
Successful replicate sample sets were taken at upwind locations to characterise the background aerosol environment, and at multiple downwind locations to capture geothermal aerosols. We also took samples of spring fluids, as the assumed local aerosol sources, and geothermal gases, which are responsible for driving bubbling activity. Ongoing work is investigating the chemical composition, biomass content and microbial diversity of aerosols, and the volatile profiles of geothermal gases. Our data will provide the first insights from natural analogues into the formation of aerosols within cryovolcanic plumes.
Read the full scientific report, with kind permission from Mark Fox-Powell.