Scientists have identified an unexpected driver behind the Cambrian explosion, the evolutionary event that rapidly accelerated biodiversity on Earth approximately 540 million years ago: ancient feces. According to a new study published in the journal Trends in Ecology and Evolution, the larger and more complex fecal matter produced by newly evolved organisms during this period enriched marine ecosystems with organic matter and nutrients, paving the way for a boom in life.
A Fecal Revolution in the Food Chain
Prior to the Cambrian period, marine life was remarkably simple and largely microscopic. However, around 540 million years ago, as organisms grew in size and developed complex digestive tracts, the nature of their waste also transformed [1]. Researchers note that these larger, heavier fecal pellets sank more rapidly from the ocean surface to the seafloor. This sinking process created a nutrient windfall for organisms inhabiting the muddy benthic zones, fostering the emergence of new life forms [2].
Altering Ocean Chemistry
According to experts, the descent of fecal matter into the deep ocean did not merely sustain benthic organisms; it fundamentally altered nutrient distribution throughout the water column [3]. This process regulated the chemical balance of marine waters, influencing oxygen levels and the distribution of other vital elements. This cycle, which began at the dawn of the Cambrian, became one of the primary catalysts for the establishment of complex ecosystems [4].
Ultimately, paleontologists emphasize that when studying the evolution of life, it is crucial to consider trace fossils and biological remnants alongside body fossils. It is suggested that a monumental evolutionary leap like the Cambrian explosion may have gained momentum thanks to these humble biological wastes that enriched the ancient seafloor.
Sources and further reading
- [1] La diversification du Cambrien, il y a 540 millions d'années ...
- [2] L'explosion cambrienne, un épisode de diversification ...
- [3] Les excréments : un ingrédient inattendu de l'explosion ...
- [4] L'explosion de la vie au Cambrian
Image & News Source: Sciences et Avenir - Archeo Paleo / sciencesetavenir.fr