Tasmanian researchers have found a living throwback to one of the earliest lifeforms on Earth.

A team from Department of Primary Industries, Parks, Water & Environment (DPIPWE) and the University of Tasmania has uncovered rare, living stromatolites deep within the Tasmanian Wilderness World Heritage Area.

Stromatolites are rock-like structures formed by micro-organisms which create layers of minerals using elements dissolved in the water in which they live.

Fossil stromatolites are the oldest evidence for life on Earth, first appearing around 3.7 billion years ago.

The researchers made the discovery during a survey of peat-bound karstic wetlands – an unusual type of swamp which occurs only in peaty soils underlain by limestone and similar carbonate rocks.

“The discovery reveals a unique and unexpected ecosystem in a remote valley in the state’s south west,” Dr Bernadette Proemse.

“The ecosystem has developed around spring mounds where mineral-rich groundwater is forced to the surface by geological structures in underlying limestone rocks. The find has proved doubly interesting, because closer examination revealed that these spring mounds were partly built of living stromatolites.”

Roland Eberhard from DPIPWE’s Natural and Cultural Heritage Division said stromatolites are rare because over the last few billion years, many more advanced life forms have evolved to feed on the micro-organisms required to form them.

“The discovery of living stromatolites in Tasmania is highly significant because stromatolites are rare globally and not previously known from Tasmania except as ancient fossils,” Mr Eberhard said.

“DNA analysis indicates that the Tasmanian stromatolites are micro-organism communities which differ from all other known stromatolites.”

The discovery provides clues as to why stromatolites thrived for millions of years but then virtually disappeared from all but a few exceptional places on earth.

The researchers believe that the highly mineralised water flowing from spring mounds is a critical factor in the ability of the stromatolites to survive in the Tasmanian wilderness, because it challenges other forms of life.

This became obvious when the researchers noticed that the mounds were littered with the shells of dead freshwater snails, which would normally feed on them.

“This is good for stromatolites because it means there are very few living snails to eat them. Fortuitously, these Tasmanian ‘living fossils’ are protected by the World Heritage Area and the sheer remoteness of the spring mounds,” Dr Proemse said.

Further surveys are planned to find more spring mounds and stromatolites at other sites in the World Heritage Area.

The team’s latest research paper is accessible here.