Young Laureates in 2014, Francesco Sauro and Hosam Zowawi joined forces for an expedition to a pristine world hidden beneath South America’s table-top mountains where they have uncovered life forms that may hold the key to critical advances in medical science.

A recent expedition by two Rolex Laureates in caverns deep beneath the table-top mountains of South America is unearthing dramatic evidence for the existence of previously unknown life on Earth – and may even hold clues to the possibility of life on Mars.

Over the past eight years, gifted Italian speleologist Francesco Sauro has explored some of the most isolated and inaccessible tepuis in Venezuela and Brazil. In 2016, he was accompanied by Hosam Zowawi, who is at the forefront in the worldwide battle against the rising bacterial drug-resistance which threatens millions of lives.

The two were hoping that in the ancient, unexplored quartzite caverns carved into the tepuis by the slow action of water, geology and biology over tens of millions of years they might find life-forms unknown to science. The findings to date are astonishing, even to them.

Zowawi and Sauro first met at a Rolex Awards ceremony in London in June 2014, and established an immediate rapport. “It was clear from the beginning that our fields of research were following complementary paths of exploration,” says Sauro. “I was seeking a microbiologist interested in studying the caves of the tepuis to understand their microbial biodiversity. Hosam was interested in finding clues to the evolution of antibiotic resistance in bacteria – and he needed to find a place where the bacteria have never had contact with humans. We discussed working together from the first day we met.”

Their shared interests led, in 2015, to an application to Rolex for additional funding to support the world’s first bio-discovery expedition into a deep cave in the tepuis, thought to be at least 30 million years old.

Sauro explains: “Only 10 per cent of the world’s caves have ever actually been explored. Of these only around 60 caves have been investigated using modern molecular biology methods. This means that the life of the deep subsurface of our planet is largely unknown – and may harbour many unique lifeforms that humans have never before encountered.”

Their early results confirm this view. “We are discovering evidence for a host of new organisms: strange, silica-dependent bacteria. Our initial analysis indicates that 40 per cent of the RNA we sampled is unclassified by science,” Sauro explains. RNA is ribonucleic acid, a fundamental ingredient of all life on Earth: it carries the instructions from our genes (DNA) and makes proteins. The unclassified RNA points to a very high probability these are novel lifeforms, never before seen.

Being shut-off from the sun and biological activity of the surface, the microbes must draw energy from the rock. This may mean they have developed unknown metabolic processes, from which scientists hope to learn much.

The target of the team’s biodiscovery expedition was the labyrinth of Imawarì Yeuta  –  the largest quartzite cave in the world, which Sauro first penetrated in 2013. Its accessible chambers and galleries extend for hundreds of metres and are abundant in rich and colourful evidence of microscopic life.

Living mats of bacteria and sediment – known as stromatolites – and other peculiar biological formations carpet the walls, floors and pools of the caves. Stromatolites are a lifeform dating back at least 3.5 billion years, to a time not long after the Earth itself formed. They are the ancient forerunners of complex, multi-celled life, which arose much later. From this deep, ancestral biology both Sauro and Zowawi anticipate important new discoveries.

Hosam Zowawi (left) and Francesco Sauro explore Imawarì Yeuta, searching for unique life forms.

In a truly international collaboration, the task of analysing the samples from the Imawarì Yeuta is being led by a scientific team from the University of Bologna, Italy, while the DNA and genomic analysis is being performed at King Abdullah University of Science and Technology in Saudi Arabia and the possible origins of antibiotic resistance studied at the University of Queensland, Australia. Sauro estimates the results will take from three to five years to obtain. In the meantime, he adds, he and Hosam hope to explore more caves around the world for primitive life.

“It was a fascinating experience. I am adventurous by nature but never dreamed I’d do this as part of my scientific work,” Zowawi enthuses. “I was leading a double life on the expedition: the life of the nine year-old boy in me, who loves nature and enjoys climbing – and the life of the emerging scientist who appreciates the uniqueness and the isolation of the field. I was truly excited to know that we are probably the only scientific team in history to describe this untouched piece of our planet Earth.

“For me, the high point was seeing the microbial life with my naked eyes. There was the colourful microbial film smeared across the surface of the blue lake – which itself was formed by a process of condensation over millions of years. And a mantle of yellow-coloured biofilm covering a large egg-like rock. I was also fascinated to see a small, purple pond.”

On the same expedition, Sauro made a separate exploration of Sarisariñama, a tepui that protrudes out of the Venezuelan jungle, its vertical rock buttresses and tree-cloaked summit creating a formidable natural fortress against adventurers. Unable to climb up or land by air, his team was forced to take the risky course of rappelling down into the forest from a hovering helicopter, to search for cave entrances hidden beneath the tree canopy.

From the air they spotted an immense sink-hole where a large river, flowing for kilometres across the crown of Sarisariñama, plunged into darkness. Into this opening to the underworld they were able to descend for 270 metres before their path was blocked by rock and black, rushing water.

“In our survey, we saw no fewer than six entrances into the underworld of the tepui,” Sauro says. Consulting with local tribespeople, the explorers found some of these entrances were woven into local legend. “From this we conclude that some of these entrances may have been located by hunters, who could have climbed up to the plateau long ago. But, without equipment, they would never have been able to penetrate far into the caverns themselves. These have probably remained pristine, undisturbed by humans for all of time.”

Because the caves are formed in quartzite, a very hard rock of volcanic origin, they are unlike the much more recent limestone karst caves most people are familiar with. One of Sauro’s goals is to unlock the secrets of their formation, to understand the subtle interplay of water, natural chemistry and life over eons, that bores these immense vents and galleries into the bowels of the tepuis – a process known as ‘arenisation’. One of the keys, he says, may be the silica-loving microbes that the expedition found.

Their discoveries may do more than shine a light on the development of life on Earth, Sauro believes. “On Mars, NASA’s Spirit Rover has discovered silica deposits that bear a remarkable similarity to those we are seeing in the caves of the tepuis. Our deposits were formed by the action of these silica-loving microbes – so the possibility arises that the Martian ones were formed in a similar fashion.”

For Zowawi, who is a microbiologist at the University of Queensland in Brisbane, Australia and an Assistant Professor at King Saud bin Abdulaziz University for Health Science, Saudi Arabia, the expedition has an urgent imperative – to avert the mounting toll of human life now being lost as antibiotic drugs fail in the face of growing resistance from deadly “superbugs”. The quest for new lifeforms with unknown properties for fighting human disease is what drew him to the tepuis. He says “While it is too early yet to speak of promising discoveries in my field, I am hopeful that our research will push the scientific boundaries – particularly in the fight against antimicrobial resistance, or at least pave the way for future breakthroughs.”

By Julian Cribb

Learn more about Francesco SauroLearn more about Hosam Zowawi

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