Cambrian 'Fecal Revolution' Fueled Complex Marine Ecosystems 540 Million Years Ago

A significant shift in how early animals fed and digested food around 540 million years ago may have fundamentally transformed Earth's oceans. A new scientific review suggests that an increase in the quantity and variety of animal feces produced during this period, known as the Cambrian period, helped distribute nutrients throughout the sea. This process, dubbed the 'Cambrian fecal revolution,' created conditions conducive to the emergence of more complex ecosystems. It was during this time that many major animal groups appeared, leading to a rapid diversification of marine life, commonly referred to as the Cambrian explosion. As animals developed more sophisticated digestive systems and consumed a wider range of food, they began producing larger and more diverse waste products. These feces acted as nutrient packets, transporting organic matter from the ocean surface to deeper regions, thereby supplying other organisms. This increased the availability of food and delivered essential nutrients to deeper ocean zones, opening up new habitats for life. Researchers analyzed evidence from over 35 fossil sites globally, including fossilized feces called coprolites, which ranged from microscopic particles to several centimeters in size. Some coprolites contained shells and animal fragments, indicating the increasing complexity of feeding relationships. Evidence of predation and preserved prey remains within fossilized digestive tracts further supports this notion. The study acknowledges that while fecal transport was a key factor, it was not the sole cause of the Cambrian explosion. Other elements, such as rising oxygen levels, environmental changes, and increased predation, also played crucial roles. The research adds a new perspective, suggesting that nutrient transport via feces may have accelerated the diversification of ocean life, laying the groundwork for modern marine ecosystems.