Could a small increase in oxygen levels lead to massive changes on Earth?

The Cambrian explosion was a period in the history of our planet. Suddenly, a large number of different complex life forms appeared.This happened between 543 and 530 million years ago, at the beginning of the Cambrian period. This event was so great that it marked the beginning of a new era (the Paleozoic Era) and the Paleozoic Era.

Previously, life on Earth consisted mainly of single-celled organisms and small multicellular organisms. So it is amazing that in just a dozen million years or so (this is the blink of an eye in the existence of the blue planet) A wide variety of complex organisms have emerged..

There is an additional mysterious element to this puzzle, which is that animals evolved at that time. A full range of different body shapes with distinctive features.such as shells, appendages, or highly complex sensory organs that have not been previously recorded, such as eyes.

Charles Darwin argued that the sudden appearance of new animals in the fossil record was a A serious challenge to his theory of evolution.. So far, it has not been fully clarified who is responsible for this. The evolutionary explosion of life.

For decades, scientists have wondered which could be responsible for the Cambrian explosion.It was previously thought that this was caused by a sudden and large increase in oxygen in the atmosphere, which led to increased oxygen levels in the oceans. However, the evidence supporting such a scenario is very limited and sometimes contradictory.

As Dr Richard Stockey of the University of Southampton says: “We weighed up many different lines of evidence, based on which Chemical composition of ancient sedimentsSome of them seem to indicate high levels of oxygen during the Cambrian explosion, while others seem to indicate that such levels of oxygen did not occur until about 140 million years later.

In their new study, the scientists conducted a comprehensive and large-scale analysis of the data. Machine learning and sophisticated statistical methods were used here. They revealed that During the Cambrian explosion, there was only a slight increase in oxygen levels in the atmosphere, which contradicts previous beliefs..

The basis for these allegations was, among other things, Uranium and molybdenum level analysis It is found in sedimentary rocks – and its concentration levels are associated with low-oxygen environments in ancient oceans.

– Only 140 million years after the Cambrian explosion, during that period Arrest“We’re seeing an increase in trace minerals at a rate that indicates the entire ocean is becoming oxygenated,” Stockey explained.

Meanwhile, the researchers believe: “Our analyses prove that it also exists.” Permanent changes in oxygen and productivity of the oceans and atmosphere On longer time scales than the Ediacaran-Cambrian ocean and atmospheric oxygenation oscillations.

Stuckey also stated: – We have shown that these Changes in ocean oxygenation It likely occurred at a time when it could have played a major role in the major ecological and evolutionary changes we see during the so-called Cambrian explosion. I’m really excited to continue exploring the extent to which these changes really did change the Earth.

“We reconstruct moderate, long-term increases in atmospheric oxygen and marine productivity,” the scientists wrote in their paper. “These changes in the Earth system would have led to increases in dissolved oxygen and food in shallow-water habitats over a broad geological time period in which major animal groups first appeared.” Meanwhile, the research revealed that “Decreases in major environmental physiological stressors were the upward drivers” of animal evolution..

They also say: “The approach is Provides some of the most direct evidence. On the possible physiological drivers of the Cambrian explosion, emphasizing the importance of Paleozoic oxygen in the evolution of the modern Earth system.

The results of the research were published in the journal. Scientific Earth Sciences.