Into the Acid
Not all field work looks the same. Some of it takes place in conditions that push both people and equipment to their limits. That was the case in May 2026, when an EXPLORA team travelled to the acidic pit lakes of Filón Centro, in Tharsis, Spain.
These lakes are extreme by any measure. Their pH sits at around 2.5 and their deeper layers contain no oxygen at all. Most life cannot survive there. However, a community of remarkable microorganisms can — and understanding how they do it is central to the EXPLORA project. If you want to know more about what kinds of microorganisms live in these environments, our article on the microorganisms of Río Tinto gives a good overview.
Who Was There
The expedition brought together three EXPLORA partner organisations. IE Universidad (Segovia, Spain) led the sampling work. Their team included Principal Investigator Prof. Irene Sánchez Andrea, postdoc Maider Echeveste, and PhD student Victoria Navas. In addition, INEGI (Portugal) sent a team with João, Bernardo, and Francisco, who brought a key new device to the field. Javier Sánchez-España from the Spanish Astrobiology Centre also took part. Finally, Mariia Pavlovska joined from the National Antarctic Scientific Center (Ukraine) as an observer, with the goal of making procedures consistent across the consortium.
The Old Way vs. The New Way
Collecting samples in anoxic, highly acidic conditions is hard. The old approach required several people working flat out, with real risk of sample loss or damage before analysis. This expedition tested two new approaches at the same time.
First, IE Universidad tested an improved method for filtering samples under fully anoxic conditions. The result was striking: 3 litres of water filtered across multiple depths in just 5 minutes. That is a major leap forward compared to earlier campaigns. Second, and equally important, INEGI brought a prototype robotic device to the field. The team controlled it with a mobile joystick from dry, clean ground — no direct exposure to the lake. The device worked. In fact, it passed every test the team put it through.
The contrast with the old way could not be clearer: three people working at full speed versus one person with a joystick and a cold drink.
Science in the Field, Sample by Sample
Back on shore, the IE Universidad team worked under a field tent to process samples right away. Speed matters here. Keeping samples cold and handling them without oxygen from the moment of collection protects the genetic material inside. That material is what makes later lab analysis possible.
These microorganisms produce some highly useful molecules. For example, they make special sugars, terpenes, and peptides that could have real value in medicine and industry. Furthermore, they do this under conditions that would destroy most other life forms. To understand why, our article on what extremophiles are and how they work is a useful starting point. For a deeper look at organisms that handle more than one extreme at once, see our piece on polyextremophiles.
Why It Matters
The samples from Filón Centro are suitable for genomic and transcriptomic analysis. In other words, researchers can study not just which microorganisms are present, but also which genes they carry and how those genes behave under stress. That level of detail opens real doors for biotechnology.
As Prof. Sánchez Andrea put it after the expedition: “With the sampling improvements we made, I expect that extreme environments will be far more accessible for scientists and future biotech applications.”
Interestingly, these extreme environments may also offer clues beyond Earth. Our article on what extremophiles tell us about the possibility of life on Mars explores that connection further.
Looking Ahead
This expedition marks a clear step forward for EXPLORA’s field research. Better methods lead to better samples. Better samples lead to more reliable science. And more reliable science brings us closer to real applications — from new enzymes that break down plastic to bioactive compounds for medicine. On that note, our article on extremozymes and PET recycling shows just how far this kind of research can go.
The microorganisms of Filón Centro have survived in acid for thousands of years. We are only beginning to understand what they can offer.
Follow EXPLORA’s research at www.explora-project.eu
