Scientists have discovered remarkably preserved fossilized microbial structures in the Moroccan High Atlas Mountains, challenging current assumptions about where the earliest life thrived. The findings, published in Geology, indicate that ancient life may have flourished in deep-water environments previously thought uninhabitable, pushing researchers to reconsider prime locations for the search for Earth’s oldest organisms.
The Surprise Discovery
Geobiologist Rowan Martindale, while studying ancient reefs in Morocco’s Dadès Valley, stumbled upon unusual wrinkly patterns imprinted on turbidite deposits – sediments laid down by underwater landslides. These “wrinkle structures” resemble imprints of microbial mats, layered communities of bacteria. However, the location of these fossils is the anomaly: they were found at least 590 feet (180 meters) below the surface, in rocks dating back 180 million years.
Traditionally, microbial mats are associated with shallow, sunlit waters where photosynthesis is possible. The deep-water setting defied expectations, as most microbial activity before 540 million years ago was thought to be restricted to shallower depths where sunlight could reach.
Life Without Sunlight: Chemosynthesis
The fossils couldn’t have been photosynthetic given the lack of light penetration, yet chemical analysis revealed high carbon levels, confirming a biological origin. Researchers now believe these microbes were chemosynthetic – deriving energy from chemical reactions instead of sunlight. This means they likely fed on sulfur or other compounds released from the surrounding rocks.
Chemosynthetic life thrives today in similar deep-water environments, where underwater landslides churn up organic material, creating energy-rich compounds like methane and hydrogen sulfide. The Moroccan fossils suggest that this process may have been a key factor in sustaining life in ancient deep-sea ecosystems.
Implications for the Search for Early Life
The discovery highlights that wrinkle structures, previously considered reliable indicators of early life, can form in unexpected environments. This implies that the search for the earliest life signs should expand beyond shallow-water formations to include rocks formed in deeper settings.
Martindale emphasizes that “wrinkle structures are really important pieces of evidence in the early evolution of life,” but now researchers must adapt their search methods to find more. The finding underscores the resilience of early life and its ability to thrive in conditions previously considered impossible.
The discovery broadens the understanding of early life on Earth, showing it was more adaptable and widespread than once assumed.
