It was believed that the seabed in the deep ocean during the Cambrian period was not suitable for life because
The tunnels of worms are their habitat, where theychewed food, including swallowing the soil and digesting it, thus moving forward and forming a tunnel. Brian Pratt thought that if the inhabitants in the deep ocean existed in the Cambrian period, then they could be very small, and therefore invisible to the human eye. Therefore, the scientist cut fossils from the seabed of that period and began to study them.
These fossils came from a region in remoteThe Mackenzie Mountains in the Northwest Territories in Canada, which Pratt found 35 years ago. Then the scientist in a digital form improved the images of the surfaces of the rocks so that he could study them more closely. Only then a hidden “superhighway” of holes appeared in the rock, made of several different sizes and types of prehistoric worm.
Some were only a millimeter in size, andothers are about the size of a finger. The smaller ones were probably made of simple polychaetes — bristle worms, but one of the larger forms was a predator that attacked unsuspecting arthropods and living on the surface of worms.
For the first time we saw evidence of a largeaggregations of worms living in sediment that was thought to be infertile. The mud on the continental shelf 500 million years ago contained mysterious worm tunnels - burrows - and more animals recycling or bioturbating the seafloor than anyone thought.
Brian Pratt, professor at the University of Saskatchewan, USA
This discovery may prompt a rethinkoxygenation levels in ancient oceans and continental shelves. The Cambrian period saw the "explosion" of life (called the "skeletal explosion" or "Cambrian explosion") on Earth in the oceans and the development of multicellular organisms, including prehistoric worms, mollusks, snails, and the ancestors of crabs and lobsters. Previously, the seas were inhabited by simple single-celled microbes and algae.
It has always been assumed that the creatures in the slateBurgess (Burgess Shale Fauna - the fossil fauna found in Burgess Middle Cambrian shale, one of the richest places in the world of paleontological finds and the best of the Cambrian period) sustain life. Pratt's discovery with co-author Julien Kimmig of the University of Kansas shows that there was enough oxygen to maintain various types of worms on the seabed.