According to new research, the action of underwater volcanoes and the ice age lead to apparition of animal life on Earth.
The planet could be described as a Snowball Earth in the period between 720 and 640 million years ago. For millions of years during this era, most of the surface was covered in ice. However, according to a study published in Nature Geoscience, underwater volcanoes were erupting beneath the ice, creating new chemical reactions.
In The Conversation, the lead author Thomas Gernon explains that the findings clarify the question why and how the suddenly melted ice changed the ocean chemistry. The study helps scientists understanding the presence of oxygen in oceans and Earth's atmosphere. According to experts, oxygen is the building block that lead the evolution of animal life from single-celled organisms into animals.
The research was conducted by scientists from the University of Southampton and it found that during the Snowball Earth the erupting underwater volcanoes played a key role in the dramatic changes on the surface of the planet.
The Snowball Earth phenomenon was created by the breakup of supercontinent Rodinia. Increased river waters coming into the ocean were changing the chemistry of the oceans. The planet was dramatically cooled by reducing the heat-traping carbon dioxide in the atmosphere. Then, the volcanic activity below the ice produced important carbon dioxide emissions, leading to a rapid greenhouse effect warming the Earth.
Dr. Gernon also explains in the publication The Conversation that one would hardly expect the apparition of complex life forms, however during this phase of extreme climate on Earth this is what occurred. Most living organisms living in the sea before Snowball Earth were just one-cell free-floating bacteria. However, the underwater volcanoes triggered high phosphorus levels that stimulated the production in the ocean of algae and other multi-cellular organisms.
The high phosphorus levels in oceans and the atmosphere also played an important role in the creation of cell membranes and DNA. This is the phenomenon that had lead the evolution of life on Earth from single-cell bacteria to today's animal kingdom.
