Phreatic

Casa
Italia
Cala Gonone
Phreatic

Phreatic exists to grow knowledge on groundwater resources & marine caves to insure their protection.

22/05/2026

How do I get involved?”
We get this question every week. Here’s the answer.

Phreatic is a volunteer group. Nobody here has a salary, a title, or a uniform. What we have is a shared conviction that submerged caves and groundwater systems deserve more attention than they currently get — and that the people who can access them have a responsibility to document what they find.
You don’t need a PhD. You don’t need a specific certification or training agency.

You need to be a competent cave diver, willing to show up, carry tanks ( LOTS of tanks), follow protocols, and contribute to something that outlasts any single dive. If you want to be part of it, the first step is a conversation.

get in touch and be part of us

13/05/2026

WATER 💧

The water that enters a cave is not the same water that exits. In between, it tells you everything.

Submerged caves aren’t just environments to explore — they’re direct windows into the health of an aquifer. Every parameter we measure is an indicator: pH tells us how acidic the water is and why, conductivity reveals mineral load and anthropic anomalies, nitrates trace agricultural pressure on the water table, dissolved oxygen measures the ecosystem’s capacity to sustain endemic life.

This data doesn’t exist without someone going in. No drone, no satellite, no remote sensor reaches a flooded passage deep under the ground .

and you never know what you might find

08/05/2026

CAVE SURVEY

No GPS. No aerial view. This cave map exists because someone went inside and measured everything by hand.

The process is called cave survey. On the surface it sounds simple: go in, measure distances and angles, record everything on a device. Underwater, with limited visibility, full equipment, and gas to manage, it’s something else entirely.

Every survey is a dedicated dive — you do explore and map at the same time or need extra dives to complete the survey. Collect all the data underwater, then process it on the surface using specialist software to produce maps and three-dimensional profiles.

The result is a document that didn’t exist before. A representation of a place that very few people will ever see directly.

This carousel walks through the process, step by step

EXPLORATION MEANS NOTHING WITHOUT DOCUMENTATION

04/05/2026

Cala Luna Project — 2026 Season Kickoff

The first project week of 2026 in Cala Luna is complete.

Our new team members stepped in strongly, bringing rebreathers past the no-mount restrictions and opening access to new sections of the system.

Cartography and survey coverage have been extended, and several potential dry leads have been identified for future exploration.

All of this was achieved in just a few days of diving.

Great logistics, awesome people, and a strong result.

A special thanks to Anze Abram and Dennis Wachter for spearheading the effort.

More to come.

24/04/2026

Every sample we bring to the surface tells the story of an entire system

You never knows what you’ll end up finding
Some times just nothing 😅

11/04/2026

CITIZEN SCIENCE :

Every diver can become a scientist.
You don’t need years of study — you need to know what to collect and how.

Tag someone who should know this.

03/04/2026

Sardinia is one of the oldest continental blocks in the Mediterranean.

The so-called Sardinian-Corsican block is a fragment of European crust that separated from the Iberian Peninsula around 20 million years ago, rotating into its current position.

Part of this block is made up of carbonate rocks — limestones and dolomites deposited in tropical marine environments between the Cambrian and the Jurassic, roughly 540 to 150 million years ago.

These rocks are soluble: rainwater absorbs atmospheric CO₂ to form carbonic acid, weak but sufficient to dissolve calcium carbonate along fractures and joints in the rock.

The process is called karstification. It operates on geological timescales: millions of years of percolation widen fractures into conduits, conduits into passages, passages into complex systems.

When the water table drops or sea level changes, some passages drain. Others remain flooded — they become the submerged caves we explore.

In Sardinia, karstification is particularly developed in the Palaeozoic limestone areas of the Iglesiente and Sulcis, and in the Mesozoic formations around Dorgali, Orosei, and the Nurra. Old, compact, fractured rock. Tens of millions of years of dissolution.

Not by chance. The result of a specific lithology, sufficient rainfall, and geological time long enough to carve what we explore today.

30/03/2026

Who wants to help us turning silence into datas ?

05/03/2026

It starts with fire.🔥

Last summer, the hills near Oliena burned.
So many hectares of Mediterranean landscape turned black.

But in karst landscapes, what happens on the surface never stays only on the surface.

When the rains return, water seeps into the limestone.
Drop by drop it disappears underground, entering a hidden world of fractures, tunnels, and flooded caves.

That invisible journey can last days, months… sometimes years.

Eventually, the water resurfaces at Su Gologone, the most powerful karst spring in Sardinia — releasing millions of liters of groundwater every day and feeding the Cedrino River.

But the real question is:

Where does that water actually travel underground?

This is what cave exploration tries to reveal.

By diving the submerged passages beneath the spring, we attempt to map the hidden aquifer and understand which basins and mountains feed this extraordinary source.

Because in karst systems, everything is connected.

The burned hills.
The rain that falls on them.
The invisible rivers underground.
And the spring that gives that water back to life.

28/02/2026

Every diver can become a citizen scientist.

And we really mean that.

If you have been thinking about how to help the environment you love diving in, how to contribute to science in a meaningful way, or how to connect with scientists doing real research in the places we explore — this is for you.

At Phreatic, we create projects that connect diver volunteers with scientists working on environmental research in Sardinia’s underwater ecosystems, including caves and coastal waters.

So this is not just about watching from the outside.
It is about taking part.
Learning.
Contributing.
And helping generate real data that supports real research.

This short video is from one of Phreatic's regular projects we carried out last year under the leadership of Peter Gärtner and with the work of his dedicated team, who have been coming to Sardinia for many years for a focused research week.

If this speaks to you, join us on a future project.

If you love this environment, you can help protect it. If you want to protect, we can show you how to do it.

(C) Video - Keith Kreitner
Project Divers - Peter Gaertner, Manuela Schoch, Kenzie Potter, Berend-Jan Velthuis, Matthias Herrmann, Frank Haupt, Timo Bortsch, MIchael Ziegler, Keith Kreitner.

Indirizzo

Via Colombo 15
Cala Gonone
08022

Sito Web

http://www.phreatic.org/, https://www.facebook.com/PBSardinia

Notifiche

Lasciando la tua email puoi essere il primo a sapere quando Phreatic pubblica notizie e promozioni. Il tuo indirizzo email non verrà utilizzato per nessun altro scopo e potrai annullare l'iscrizione in qualsiasi momento.