Evolution in Elemental Oceans

A new study on the evolution of life as related to the diversity or scarceness of some chemical compounds in the oceans may shed new light on the steps to follow in the attempt to investigate the possible presence of life in the oceans of alien worlds. Life is not restricted to water, though; instead, it involves a bit of most of the elements, such as plants, air and sunlight, in various forms and amounts. These must be taken into consideration when “following the water,” study says.

Ariel Anbar, a professor in ASU's Department of Chemistry and Biochemistry and the School of Earth and Space Exploration in the College of Liberal Arts and Sciences, is the leader of a research that combines biology, chemistry, biochemistry and geoscience. His study involves the evolution of some important nutrients through the history of the oceans, suggesting the way further research should be conducted in the future.

 

"The history of our planet is like a natural laboratory of 'alternative worlds,'" shares Anbar, quoted by Scientific Blogging. "The chemical composition of the oceans has changed dramatically over billions of years. Elements that are abundant today were once scarce, and elements that are scarce today, were once abundant. So, the Earth's ancient oceans are a good place to go if we want to understand how organisms and ecosystems evolve to cope with changing abundances of elements. Studying the ancient oceans also forces our minds to imagine what we might find some day in alien oceans on other worlds."

 

The composition of the old oceans can be inferred from the sedimentary rocks on their bottom, which should provide insight on the abundance of key elements such as sulfur, nitrogen, phosphorus, copper or the like. "Take iron, for example," he reckons. "It's needed by virtually every organism on the planet. Is that because the basic biochemistry of life on Earth developed in the iron-rich oceans of Earth's distant past? Or is it because the chemical properties of iron are so special that evolution would have selected for it even if it was always rare?" Hopefully, studies will provide a clear answer to this kind of questions.