Several years ago, a series of huge lava tubes were discovered on the Spanish island of Lanzarote, just west of North Africa. Now, a team of international researchers have just completed the first detailed study of the minerals and microorganisms that exist within them.
According to the scientists, the caves, formed by cooling lava after volcanic eruptions, shed light on Earth's ancient ecosystems – and they could be significant in the search for life on Mars, too.
The work, led by Professor Bogdan P. Onac from the University of South Florida’s School of Geosciences, alongside scientists from Portugal, Spain and Italy, was published recently in Communications Earth & Environment.
Into the caves
Using sterilised stainless-steel tools, such as scalpels and chisels, the team collected mineral deposit samples from six recently discovered lava tubes on Lanzarote: Cueva Paso Esqueleto, Cueva de Montaña Rajada, Cueva de Maguez, Cueva Las Breñas, Cueva de los Naturalistas and Cueva Monte Corona Puerta Falsa.
They then used a combination of advanced molecular, isotopic and mineralogical techniques to analyse the mineral deposits.
"While the lava tubes on Lanzarote were discovered several years ago, we are the first to complete such a detailed study of minerals and microorganisms," says Onac.
The researchers found that the volcanic rock within the lava tubes had created a natural shield, preserving minerals and organic compounds from weathering. This protective environment has helped maintain biosignatures (substances, patterns or features that can be used as evidence of life on a planet, past or present), including calcium and sodium sulphate.
The discovery provides evidence that microbial activity and microorganisms, such as bacteria, were once active in the caves.
Why is this exciting?
"This study adds to our understanding of geological and environmental changes on Earth and highlights lava tubes as potential refuges for microbial life, holding significant implications for astrobiology, particularly in identifying biosignatures on Mars and other celestial bodies," says Onac, explaining that Martian lava tubes are similarly shielded to Earth's and therefore may also hold signs of past microbial life. These insights could even help guide missions aimed at assessing Mars’ habitability, he adds.
The researchers plan to publish additional studies on the Lanzarote lava tubes in the coming months. They also have plans to investigate newly formed lava tubes in Iceland, expanding their exploration of these remarkable geological features.
Main image: Timanfaya National Park, Lanzarote/Getty
Find out more about the study Decoding organic compounds in lava tube sulfates to understand potential biomarkers in the Martian subsurface
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