Volker Vahrenkamp, a geology professor at King Abdullah University of Science and Technology (KAUST) in Thuwal, Saudi Arabia, has recalls an unexpected yet fortunate discovery. “Sometimes, these things need a little luck,” he remarks with a smile. Vahrenkamp and his team embarked on a mission to investigate coastal geological formations identified via satellite images.
These formations, known as teepee structures, are tent-shaped sedimentary deposits found in intertidal zones and serve as important indicators of both ancient and modern environmental changes. In their discovery journey, they found prime examples of these structures just 400 kilometres from KAUST, near the southern tip of Sheybarah Island, a location renowned for Red Sea Global’s luxury tourism resort. “There aren’t many good examples of teepee structures where people can study how they form,” Vahrenkamp said, in a report by Arab News.
“We spotted this, and it’s the most spectacular example I’m aware of.” The satellite images revealed two teepee fields in the island’s intertidal zone. A short boat trip on a converted fishing boat brought the team to the island, where they examined one field before crossing the foreshore to the other. It was then that they stumbled upon stromatolites. Stromatolites are layered rock-like formations created by tiny, often invisible microbes that trap sediment in their filaments.
Found in intertidal zones, these structures are alternately covered and uncovered by tides, slowly transforming captured minerals and sand grains into solid masses through biomineralization. Stromatolites are fascinating geological structures that offer a window into the earliest forms of life on Earth. These layered rock formations are created by the activity of microorganisms, primarily cyanobacteria, which trap and bind sediment with their sticky filaments. Over time, the accumulation of these sediments forms solid, layered structures.
Stromatolites hold significant historical value because they provide evidence of life dating back approximately 3.5 billion years. These ancient organisms played a crucial role in the development of the Earth’s atmosphere through the process of photosynthesis, which produced oxygen as a by-product. This Great Oxidation Event drastically transformed the planet’s atmosphere and enabled the evolution of oxygen-dependent life forms.
Despite their ancient origins, living stromatolites can still be found in certain parts of the world today, although they are much rarer.
They typically exist in extreme environments where few other life forms can survive, such as highly saline lagoons and alkaline lakes. Modern stromatolites serve as valuable analogs for their ancient counterparts, allowing scientists to study the ongoing processes and microbial interactions that lead to their formation. Discoveries of living stromatolite colonies, like the one recently found off Sheybarah Island in Saudi Arabia, provide unique opportunities to better understand the complex history of life on Earth and the environmental conditions that supported its development.
These modern examples are not only scientific treasures but also crucial for piecing together the evolutionary puzzle of life’s early history. Cyanobacteria, the microbes responsible for stromatolites, have been around for about 3.5 billion years and are critical to life on Earth. These ancient organisms were among the first to perform photosynthesis, a process that produces oxygen as a by-product. Scientists believe cyanobacteria were pivotal in the Great Oxidation Event, which transformed Earth’s atmosphere and enabled the evolution of oxygen-dependent life forms.
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Today, most stromatolites are fossils, having lost their dominance in the oceans to competitors like coral reefs. However, the discovery on Sheybarah Island provides a rare opportunity to study living examples of these ancient structures and further understand the environmental conditions that allowed them to thrive. In some parts of the world, “modern” living stromatolites, described by Vahrenkamp as “analogs for their ancient counterparts,” continue to thrive. “Stromatolites are a vestige of the earliest life on Earth,” he explains. “They ruled the Earth for an incredible period of time, about 3 billion years.
Today, they are part of the rock record in many parts of the world, but from these old rocks, it is impossible to work out what type of microbes were involved and exactly how they did what they did.” This is why discovering a rare colony of living stromatolites, like the one off Sheybarah Island, is invaluable to geologists, biologists, and environmental scientists. “When you find a modern example such as this, the chances are that you might be able to better understand how the interaction of this microbial community led to the creation of stromatolites,” Vahrenkamp said.
While other examples of living stromatolites exist, they are typically found in extreme environments like alkaline lakes and ultra-saline lagoons, where competition is minimal. A previous colony was discovered in a more typical marine environment in the Bahamas, which Vahrenkamp has visited, aiding in his quick recognition of the formations on Sheybarah Island. However, this marks the first discovery of living stromatolites in Saudi waters. The exact age of these stromatolites remains uncertain, but Vahrenkamp provides some context.
“We know that during the last Ice Age, the sea level here was 120 meters lower, so they were not there 20,000 years ago. The area where they are now was flooded about 8,000 years ago to a height about 2 meters above where it is now, and then the sea level receded again to where it is now about 2,000 years ago.” This doesn’t necessarily mean the stromatolites are 2,000 years old, as the precise timeline for microbial activity to create these layered structures is still unknown.
“No one has yet come up with a good way of dating the layers,” he added, highlighting the ongoing mystery and scientific intrigue surrounding these ancient life forms. Stromatolites, both ancient and modern, are remarkable geological and biological phenomena that offer profound insights into the early history of life on Earth. Their unique ability to record the activity of some of the planet’s earliest life forms makes them invaluable to scientists studying the evolution of life and the development of Earth’s atmosphere.
The discovery of living stromatolite colonies, such as those off Sheybarah Island, provides a rare and precious opportunity to observe and understand the processes that have shaped life over billions of years. As research continues, these formations will undoubtedly contribute to our knowledge of ancient microbial life and the environmental conditions that allowed such life to flourish, underscoring their importance in the scientific community and beyond.
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