SHARK BAY, WESTERN AUSTRALIA, 2003

Stromatoliths in the sunset

Lanting© Frans Lanting

There are naturally-occurring extraordinary fossils that are testimonials of past ages, allowing us to thus reconstruct the scenario of the origins of life on our planet with a certain precision. These include stromatoliths, layered sedimentary structures, often column or dome-shaped, which developed along the edges of fresh water, marine and evaporitic environments. They are thought to be a good 3.5 billion years old. They date back to the Pre-Cambrian period and were particularly abundant in the Paleozoic period, which makes them so very interesting.
The main school of thought is that they have biogenic origins, which means that the layers are made up of microbial mats and mineral granule deposits. The solid structures were likely to have been formed by the biological activity of algae and cyanobacteria in marine environments. The alternative opinion instead sees them as inorganic marine bed or lake precipitates, built up over the long geological eras. In any case, whether they are fossils or are still biologically active today, ancient organisms could be enclosed with stromatoliths, which could give us a much clearer understanding of the features of the earliest life forms and the environments in which they lived.
The problem for scientists lies in finding good examples of stromatoliths, since they have been subjected to huge changes in the biology and chemistry of marine waters. Because they exist in environments with a certain composition, an event like rising sea levels, caused by climate change, would flood the areas in which they are found, ruining their structure and the equilibrium of the organic habitat that helps preserve them.

Aurora Licaj