What makes an extremophile “extreme”?
Extremophiles are organisms that thrive where most life cannot: extreme cold, salinity or pressure. In Antarctica, cold-loving (psychrophilic) microbes, including bacteria, archaea, fungi and algae, sit at the base of local food webs. They also drive the cycling of nutrients. However, each species has adapted to a narrow range of temperature, salinity, ice cover and nutrients. Move those conditions, and the whole microbial community can shift with them.
Antarctica is one of EXPLORA’s two extreme sampling sites, alongside the naturally acidic Rio Tinto river in Spain, where the project recently completed a robotic sampling expedition at Filón Centro. The project’s first step is sustainable sampling: collecting extremophiles using low-impact technology, under strict legal and ethical frameworks. In Antarctica, this fieldwork relies on Ukraine’s National Antarctic Scientific Center (NASC). NASC is the national polar operator, and it runs the year-round Akademik Vernadsky station on the West Antarctic Peninsula.
How Antarctica is changing
The West Antarctic Peninsula is one of the fastest-warming regions on Earth. Over recent decades, it has experienced summer heatwaves and marked losses of sea ice. For microbes adapted over millennia to a stable cold, even small shifts are not trivial.
The sea reflects this closely. A 2025 study around the West Antarctic Peninsula found that marine microbial communities are strongly shaped by water temperature and sea ice. In fact, two sites only 400 kilometres apart hosted strikingly different communities, each tracking its own local climate [1]. In other words, microbes act as sensitive recorders of the conditions around them, not unlike the polyextremophiles EXPLORA studies in the Rio Tinto.
Meanwhile, melting ice adds another layer of change. As glaciers retreat, freshwater lowers the salinity of coastal waters. It also releases nutrients and trace elements, reshaping which microbes flourish. In Chile Bay, on the Western Antarctic Peninsula, freshening from nearby glaciers shifts the coastal bacterial community [2]. As a result, researchers have documented comparable meltwater-linked differences in East Antarctica [3]. Such changes can ripple upward to the phytoplankton blooms that feed the wider ecosystem.
None of this is abstract. These communities are early indicators of ecosystem change. They are also a reservoir of biodiversity that scientists have barely begun to understand, echoing the questions EXPLORA is asking about microbial life in the Antarctic dry valleys. How these fragile ecosystems respond to change matters twice over. It matters for the biodiversity itself, and because the biology found there could inform future, nature-based biotechnology, including the extremozymes EXPLORA is exploring for PET recycling.
Questions & Answers
What is an extremophile? An organism that thrives in conditions most life cannot tolerate, such as extreme cold, acidity, salinity or pressure. Antarctica’s cold-loving microbes are a classic example.
If they survive extremes, why would climate change threaten them? Because each species is adapted to a specific range, not to change itself. Shifts in temperature, sea ice, salinity or nutrients can favour some microbes over others and reorganise entire communities.
Why do tiny microbes matter for the rest of the ecosystem? They form the base of Antarctic food webs and drive nutrient cycling. When microbial communities shift, the effects can move up the chain. For example, they can reach the phytoplankton blooms that feed larger life.
What is EXPLORA’s role? EXPLORA studies Antarctic microorganisms and develops precise, sustainable ways to sample them, building on the same sustainable sampling approach used at Rio Tinto. Its research is exploratory. It focuses on understanding this biodiversity and its potential for future biotechnology, not on delivering a finished solution.
Curious how EXPLORA is exploring life at the other extreme? Read about the project’s work at Rio Tinto or browse all EXPLORA news.
