Expeditions
at the edges of life
From a 50°C acidic spring in Wyoming to a geyser in Iceland: six decades of field journeys to collect the extremophile algae that live where almost nothing else survives.
Algae hunters
in boiling water
In the planet's most acidic and hottest thermal springs — pH below 3.0, temperatures between 35 and 50°C — a small group of unicellular red algae in the genera Cyanidium and Galdieria survives. They are extremophile organisms, able to live in conditions lethal to almost every other form of life.
The ACUF collection grew out of fieldwork by generations of researchers who, from the 1960s to today, collected these strains in springs, geysers, and acidic pools across Italy, the Americas, Asia, and Northern Europe. This is the map of their journeys.
The Beginning: Paolo De Luca
on the trail of Cyanidium
Between 1967 and 1968, Professor Paolo De Luca explored several American hot springs, collecting samples from sites with pH below 3.0 and temperatures between 35 and 50°C. The first strains were isolated from those samples and are now classified as Galdieria yellowstonensis, G. sulphuraria, and G. mesoamericana.
The acidic terraces of Yellowstone
The first sampling in ACUF history. The strains that would give rise to the collection were isolated from the park's thermal waters: the beginning of research that continues to this day.
Archive photo, P. De Luca expedition, 1967.
The expedition to Los Azufres
One year later, De Luca collected samples at Los Azufres, in Mexico, expanding the research beyond U.S. borders toward a second major geothermal field.
Archive photo, P. De Luca expedition, 1968.
On Mount Lawu, where everything had already been written
At Mount Lawu, where C. caldarium had first been described in 1936 by Professor Lothar Geitler of the University of Vienna, De Luca isolated a strain that still represents the authentic strain of Galdieria javensis, still preserved in the ACUF collection.
Roberto Taddei
and the Italian exploration
Between 1974 and 1979, 120 low-pH environments scattered across Italy were explored by Professor Roberto Taddei and his team: systematic work, site by site, to map the country's extremophile habitats.
A map of the acidic country
From the Alps to Sicily, Taddei's team identified and sampled more than one hundred thermal and acidic environments: springs, geysers, pools, and fumaroles, often in remote and poorly documented areas.
Notes, coordinates, samples
Taddei's notebooks record every site visited: temperature, pH, the appearance of the pool, and the sampling date. A handwritten archive that today tells the origin story of dozens of strains in the collection.
Alì Terme and the acidic pool of Vulcano
At Terme Granata in Cassibile and in the acidic pool on the island of Vulcano, in the Aeolian Islands, two of Sicilian volcanism's most characteristic environments were sampled.
Petriolo Terme and the Sasso Pisano geyser
In the geothermal heart of Tuscany, between the thermal springs of Petriolo and the geyser of Sasso Pisano, the research finds two of the most photogenic — and most productive — sites of the entire Italian campaign.
Italy, without interruption
The exploration of Italian sites has never stopped: from Larderello to Campania, every decade adds new strains to the collection.
The handover at Larderello
Roberto Taddei and Claudia Ciniglia together in the field at Larderello: the generation that founded the collection meets the one that would carry it into the world.
The fumaroles of Pisciarelli
In the Phlegraean Fields, a stone's throw from Naples, one of the most active sites and one of the closest to ACUF headquarters: sulfurous vapors and brightly colored mineral deposits.
Among the vapors of the Mefite d'Ansanto
One of Europe's most intense natural gas emissions, known since antiquity for its toxicity: an environment as extreme as it is fascinating for research.
The most recent exploration: Petrinus
The thermal waters of Petrinus, in Campania, show that field research continues: half a century after Yellowstone, new strains are still being sought close to home.
Beyond Italy, around the world
Alongside the Italian campaign, the exploration of low-pH environments expanded to other continents: from Icelandic geysers to the thermal springs of Anatolia.
Eight sites, one journey
In a single expedition, Claudia Ciniglia sampled eight Icelandic geothermal sites, from solfataric fields to geyser areas.
- ST1 — Gunnhuver
- ST2 — Seltun
- ST3 — Hveragerði
- ST4 — Nesjavellir
- ST5 — Geysir
- ST6 — Víti
- ST7 — Bjarnarflag
- ST8 — Landmannalaugar
The lunar landscape of Iceland
Boiling muds, solfataric fields, and active geysers: a landscape worlds apart from the Mediterranean one, yet just as rich in extremophiles.
Toward Anatolia
Six years after Iceland, a new expedition — this time with Turkish collaboration — brought the research group among Turkey's thermal springs.
Thermal springs of Anatolia
Among volcanic rocks and turquoise pools, the Italian-Turkish collaboration further expanded the world map of low-pH environments gathered in the collection.
Six decades of expeditions. A living collection.
From Yellowstone to springs just outside Naples, every expedition has added a strain, a data point, a story to the ACUF collection. Field research continues to this day.
