Biologists have discovered ancient living organisms that lived on Earth more than three billion years ago on an island in the Red Sea. The researchers analyzed the age of the find and examined the bacteria living inside it. Nothing like this had ever been seen before on the coasts of the Middle East.

Planet Earth has existed for 4.55±0.01 billion years. And life lived here for most of that time, for at least four billion years by some estimates. However, exactly when it emerged is still unknown to science. However, people know which form of life prevails in the initial stages – stromatolites. They consist of microbial communities, cyanobacterial mats or eukaryotic algae that form carbonate sediment at the bottom of reservoirs.

These are fossils of multicellular organisms with a layered structure that lived mostly in the Archaean and Proterozoic periods; The oldest find dates back to 3.7 billion years ago. Stromatolites are an ideal object for studying the early evolution of life on our planet because they are sometimes found alive. Of course, very few such formations remain, and they are often found in biomes with extreme conditions, such as hypersaline or alkaline water bodies. Stromatolites have been found in lakes in Cuba, Mexico and other countries. Only twice in the seas – in Australia and the Bahamas.

Biologists from Saudi Arabia have discovered a new region inhabited by living stromatolites. Ancient organisms were found on the island of Shaybara in the Red Sea. It is located on the Al Wajh carbonate platform, almost completely surrounded by a belt of reefs and corals. Sheibar is one of the 92 islands of this platform; Their maximum height above sea level does not exceed two meters.

Researchers visited the island in January 2021; They collected field data with a drone, recording the ambient temperature and the salinity of the sea surface (in winter it can reach 41 ppm, 4.1% salt per liter). They drilled a core and conducted laboratory studies (X-ray microscopy of sections, etc.) to date the corals. The results of the scientific study are published in the journal. Geology.

The age of the underlying coral layer was determined by the carbon-14 isotope; This layer was formed in the Holocene in 5264 BC. And the growth of stromatolites began only 300-400 years ago or later. These groups of bacteria are distributed over an area of ​​more than 50,000 square meters.

The authors of the article divided them into three types according to the degree of sediment compaction (lithification). The first type consisted of diamond-shaped or sinusoidal structures, colored light gray-green or dark brown. The second type was oval or in the form of clusters of tables with an area of ​​\u200b\u200bup to 100 square meters. The third is irregularly shaped, slightly compressed, and covered with a thin layer of white carbonate sand.

The microbial composition of the stromatolites found is diverse. Filamentous cyanobacteria were found with calcium and magnesium carbonate crystals unique to this life form. Additionally, these mats consisted of single-celled algae and protobacteria colonies. Biologists explained their formation with features of ecology. Tides regularly moisten the stromatolites, there are almost no storms in this region, and the surface is extremely salty.

An unusual fact turned out to be stromatolites in the form of web threads (they look like tubes with many identical holes). Previously, such formations were found only in caves. And according to researchers, they are ubiquitous on Shaybara Island. And its origins remain unclear. Since such a life form has not been found in the ocean in the Middle East, the discovered stromatolites will still be studied. The place may also become attractive to ecotourists or a nature reserve.