Credit: La Venta- Alessio Romeo
Right now, geologist Francesco Sauro and microbiologist Ana Zélia Miller are inside a recently erupted volcano in Iceland investigating microscopic ecosystems that have formed in caves as a direct result of recent volcanic activity. The research team is exploring minerals and materials that can only form in very specific conditions, specifically looking at bacteria sourced from the extreme environment that may contribute to the development of new antibiotics and therapeutics. Their findings may also shed light on how various life forms develop in post-volcanic-eruption environments, providing clues for the future colonization of Mars.
The researchers are at the tail end of their 10-day expedition now, but spoke to Labcompare right before they left for Iceland, detailing their training for the extreme environment, what they hope to find in the caves, and how a desktop scanning electron microscope analyzes their lava samples in real-time.
Q: What are your main research goals?
Ana Zélia Miller, microbiologist and integrated doctorate member of the Laboratorio HERCULES at Evora University (Portugal): My main research goals are focused on geomicrobiology of subterranean environments, including volcanic caves and mines. Geomicrobiology is an interdisciplinary field of science that investigates the interactions of microorganisms with geological substrates. This includes microbial diversity and function, and the role of microbes to dissolve minerals and mediate mineral precipitation processes, known as biomineralization. Particularly, I am interested on the microbial communities and their activities within cave environments formed by volcanic processes, such as in lava tubes from Canary (Spain), Selvagens (Portugal), Easter (Chile) and Galapagos (Ecuador) Islands, as well as the Monte Etna in Sicily (Italy). My research interests also include the recognition of traces of life (known as biosignatures) preserved in volcanic rocks for geological timescales, and the reconstruction of past environmental conditions recorded in lava tubes.
Q: How does the recent volcanic activity change the microscope ecosystems of the caves? What's the difference between the bacteria before and after an eruption?
Ana: Volcanic caves are formed at the same time of a volcanic eruption, when the lava flows from a volcano, forming lava tubes after solidification. These cavities are sterile environments at the time of their formation, but upon cooling they provide unique habitats for microbial communities to thrive. They are rapidly colonized by microorganisms, such as chemoautotrophic bacteria. These microbes grow using the mineral components of a rock without any presence of organic matter.
Q: When you enter a cave, visually, what are you looking for?
Francesco Sauro, geologist and speleologist at the University of Bologna, who conducts and leads trainings on planetary geology at the European Space Agency: Exploring lava tubes is a fascinating endeavor. We have to keep in mind that exploring volcanic caves can be hazardous. So, first we need the necessary permissions to access the lava tube locations, and always prioritize safety. For this, we need to count on experienced cavers for guidance, and be equipped with individual protective equipment, including helmets, headlamps, sturdy footwear, protective clothing, etc.
Ana: I bring all the necessary sampling tools, such as sterile scalpels, scoops, vials and sampling bags to collect microbial samples. As a geomicrobiologist, I search for signs of microbial mats within the lava tubes. These are colored microbial colonies that often appear as white, yellow or pink thin and slimy biofilms or patches coating cave walls and mineral formations, such as lava stalactites or secondary minerals, such as gypsum and calcite. These microbial mats are frequently found in areas with percolating water or moisture, as they are more likely to support microbial growth. Once the microbial mat samples are collected, they are transported under cold storage conditions and analyzed in our molecular biology laboratory. We perform techniques such as DNA sequencing, electron microscopy and culturing procedures to provide insights into the microbial community composition: who are they? what are they doing with their metabolic capabilities? how are they adapting (potentially) to the lava tube environment?
Q: How and in what ways will your research and anticipated results contribute to real-world developments?
Ana: The study of the geomicrobiology of volcanic caves, such as those found in Iceland, has implications for various scientific disciplines, ranging from microbiology and ecology to astrobiology and geology. It helps us understand the diversity of microbial life, global biogeochemical processes (e.g., carbon fixation, sulfur oxidation, and nitrogen transformation), genesis of cave minerals and offers potential applications in biotechnology and space exploration.
Francesco: The mineralogical composition and extreme conditions found in volcanic caves can mimic the conditions on early Earth or other planets. By studying the microbial life in lava tubes, we can thus investigate the origin and early evolution of life on Earth and gain insights into the potential for life to exist in extreme environments elsewhere in the universe, such as on Mars, which contain lava tubes and a record of secondary mineralization. Hence, lava tubes on Earth, such as Icelandic lava tubes could house analogues of bacterial life forms on Mars’s subsurface.
Q: What scientific instrumentation do you take with you in this challenging environment, and what is their research purpose?
Ana: One of the scientific instrumentations to highlight in this expedition to Iceland lava tubes is the Thermo Scientific Phenom XL G2 Desktop SEM, a compact and desktop-sized SEM that offers high-resolution imaging capabilities. It is important to note that SEMs are not typically portable and require a controlled laboratory environment due to their size, delicate nature and power requirements. Therefore, they are not used directly within caves. Instead, cave samples are usually collected and transported to a laboratory for high-resolution imaging and elemental analysis using a SEM. Yet, in collaboration with Thermo Fisher Scientific, we transported a Thermo Scientific Phenom XL G2 Desktop SEM to the remote Selvagens Islands in the North Atlantic Ocean, where we explored for the first-time cave samples directly in the field. We were able to detect the presence of bacteria in samples collected from the volcanic caves of Selvagens to study the morphology of cave minerals and recognize microfossils preserved in rocks, which provided insights into evolutionary processes. These findings allowed us to select the best sampling points to collect mineralogical and microbiological samples without the need to transport them to a laboratory setting. In Iceland, from a geomicrobiology point of view, the Thermo Scientific Phenom XL G2 will be used to examine the potential presence of pioneer microorganisms in the newly formed lava tubes and their possible interactions with the cave minerals.
Q: How do you combat the debilitating wind gusts and other weather-related elements?
Francesco: The Phenom XL G2 will be installed in a tent camp a few tens of meters from the lava flow, in order to analyze the samples collected in the lava tube only few minutes after they have been collected, preserving biosignatures and the potential presence of meta-stable mineralizations. The tent will have to sustain strong winds and rain. This is endeavor is made possible by the logistic organization of La Venta Esplorazioni Geografiche, which is leading the research project. A team of experienced speleologists from La Venta will support the scientists in the collection of samples and exploration of the lava tubes.
Q: What surprised you the most about preparing for the expedition?
Francesco: There are plenty of details that had to be considered in order to install an efficient lab directly on a volcano. These include not only the logistics, but also a very coordinated organization with local institutions. The project is run in collaboration with the University of Iceland, the Institute of Natural History of Iceland and “Vedurstofa” the meteorological office. This last will provide continuous support and monitoring in order to be efficient and safe while running all the scientific activities.