We know that hydrogen, the most abundant element in the universe, acts as the basic building block of life in multiple ways. On the one hand, it is the bond that makes the water molecule so stable. On the other hand, it is the source of light that comes from our sun, which is comprised of 75% hydrogen and 25% helium. What we do not know, though, is the sequence of events that made light from the sun and water on Earth interact and produce the right conditions for life to flourish on our planet. An interesting paper in Nature a couple of weeks ago sheds light on how this may have happened, some 650 million years ago.
Hydrogen, in the form of light from the sun and water in our primordial oceans, interacted to give rise to life and biodiversity. Photo credit: Credit: NASA/Kathryn Hansen
We also have a pretty clear idea of how water came to our planet. Hydrogen, the most basic of elements, powers every source of light we see in the sky. When subjected to the pressures inside stars, it creates all the other elements that make up matter, which are liberated when stars end their lives as supernovas. These elements, alongside hydrogen, create space dust, which gravity slowly carves into disks that form new stars and the planets around them. In the past decade since NASA’s Kepler space telescope was launched, we have found more than a thousand exoplanets, one of them is our closest star neighbor, Proxima Centauri. Some of the hydrogen and oxygen in the dust that is left over after planets are formed interact, giving rise to ice comets that deliver water to rocky planets. Many of these comets crashed into Earth, delivering much of the water in our oceans.
Life is a different matter when it comes to figuring out how it got started. We have not yet been able to successfully experiment with any lab process that yields a living organism out of simpler elements or even out of chains of amino acids, which are the basic building blocks of DNA. What we know is that hydrogen, in the form of water and light, is essential to produce the reactions required for cells to form. Hydrogen is also an essential ‘glue’ that makes the DNA helix stable.
Little by little, science is completing the puzzle of life. The paper in Nature referenced earlier is accurately titled, “The Rise of Algae in Cryogenian Oceans and the Emergence of Animals.” It brings us closer to understanding how complex life “exploded” around 650 million years ago. The BBC wrote an article on the dense paper, in which it summarized, “A planetary takeover by ocean-dwelling algae 650 million years ago was the kick that transformed life on Earth.” This theory was made plausible by the discovery of “invisibly small traces of biomolecules dug up from beneath the Australian desert,” which point to the “explosion in the quantity of algae in the oceans” by a factor of 100,000-to-1 around 650 million years ago after a global ice age.
These primitive algae evolved to use water and light from the sun, to thrive and multiply, covering most of the Earth’s oceans. According to lead researcher Jochen Brocks, the change in the food web caused by this algae explosion that allowed the first microscopic animals to evolve “is one the most profound ecological and evolutionary transitions in Earth’s history.” For over three billion years before this algae explosion, single-celled organisms populated the oceans without much evolutionary innovation.
Paradoxically, there was a period in our history when an excess of CO2 was good for nurturing life on our planet. According to the researchers behind the Nature paper, the proliferation of algae in the oceans “happened just after one of the greatest environmental catastrophes the planet has ever seen—the ‘Snowball Earth’ period when ice extended from pole to pole; even at the equator, temperatures could have plunged to minus 60 degrees. The BBC goes on to report, “The episode ended after 50 million years, when the build-up of volcanic CO2 in the atmosphere created a super greenhouse that melted the ice in a second cataclysm,” which warmed the oceans and enabled algae to evolve.
The final step towards the rise of complex life, according to these researchers, happened because “it was algae at the bottom of the food web that created this burst of energy and nutrients that allowed larger and more complex creatures to evolve.” Since then, plants evolved to harvest the light from the sun, which powers photosynthesis, while animals thrived in water for millions of years before moving to dry land. The carbon cycle behind the interaction of life, light, and water has been stable for hundreds of millions of years, providing the mild climate conditions required for life to thrive.
Keeping CO2 as a Life-Nurturing Substance
Besides hydrogen, carbon is also a building block for all life as we know it. All cells need and use carbon; when plants and animals die, they are literally full of it. Geology had a hand in converting the living organisms that died millions of years ago into the hydrocarbons we use every day to power our civilization.
A mild planet is good for life; a warm one is not. As we burn oil and gas, we liberate the ancient carbon that lay underground for millions of years back into the atmosphere, which has a measurable effect in warming our planet. The ideal civilization is one that uses a mix of hydrocarbons and sustainable energy in a way that helps our planet keep the right balance of carbon in our atmosphere. Hydrogen, the element that started it all, can help move us in the right direction. Our work on Hydrogen 2.0, which produces hydrogen energy from water without carbon emissions, can provide a boost of clean energy that helps us achieve this balance.
We may never be sure how complex life got started. However, we know the interaction of water, light, and life—all powered by the universe’s most abundant element—will continue to power life. We envision a day when hydrogen, which is also the most plentiful element here on our blue planet, can power much of our civilization, helping us to keep the delicate balance of life in check.
As the Hydrogen 2.0 ecosystem gains momentum, we’ll be sharing our views and insights on the new Hydrogen 2.0 Economy. We also update our blog every week with insightful and current knowledge in this growing energy field.