Ideal Iron Conditions Needed for Life to Strive on Earth and Other Planets

Iron is an essential nutrient and irreplaceable component needed for life to grow and thrive. According to a paper in Critical Care, iron is crucial for plants, bacteria, animals, and humans to transport oxygen throughout the body via hemoglobin and produce energy through electron transfer in mitochondria.

A new study also suggests that iron is a driver of evolution on Earth and other planets. Researchers from the University of Oxford have uncovered the mechanisms that influenced the development of complex life forms that will help understand how advanced these life forms could be on other planets in the Solar System or exoplanets beyond.

Iron Important for the Development of Life

Phys.org reported that the importance of iron goes back to the formation of Earth. The conditions set the rocky mantle of Earth under how it was formed and had major effects on how it affects the development of life.

In the study, titled "Temporal Variation of Planetary Iron as a Driver of Evolution," published in Proceedings of the National Academy of Sciences, researchers describe the influences of iron on planetary habitability.

Study co-author Jon Wade, Associate Professor of Planetary Materials at Oxford's Department of Earth Sciences, said that the initial amount of Earth's iron is determined by the conditions of planetary accretion when the planet's metallic core is segregated from its rocky mantle.

For instance, too little iron on the rocky planet Mercury has made it uninhabitable. Moreso, too much iron like Mars also made it challenging for the planet to keep water on the surface for times relevant to the evolution of complex life on the planet.

Researchers believe that iron conditions on Earth would have been optimal to ensure surface retention of water. They also pointed out that iron is soluble in seawater, which makes it more available to give simple life forms to develop.

But the Great Oxygenation Event, wherein oxygen levels on Earth started to rise, has created a reaction with iron and led iron to become insoluble. Due to this, gigatons of iron dropped out of seawater ad became less available for developing life forms.

Hal Drakesmith, the study co-author from Oxford's MRC Weatherall Institute of Molecular Medicine, said that the even had led iron to find new ways to obtain iron it needs. This includes infection, symbiosis, and multicellularity that help them efficiently capture and use the scarce but vital nutrients.

Adopting these characteristics pushed early life forms to become more complex and evolved into what they are today, Drakensmith added.

Finding Iron Will Help Scientists to Determine Whether Planets Could Host Life

In a similar report in EurekAlert! researchers said that iron is a driver for the evolution and development of complex organisms that can acquire poorly available iron. This could imply how complex life forms could be on other planets.

Drakesmith says that their concepts could show that the conditions to support the start of simple life forms are not enough to ensure subsequent evolution would successfully continue the development of complex life forms. He emphasized that selection is still needed just as life is on Earth to find a new way to access iron, which may be rare or random.

The team said that the study's findings show the importance of iron in the evolution of life and can be used to search for suitable planets that could host life. It may now be possible to narrow the search of planets capable of supporting life by assessing the amount of iron on the exoplanet's mantle.

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