Despite years of research, many aspects of life’s origins and early evolution remain a mystery to researchers. A new paper from the University of California, Riverside, provides new insights that could pave the way for further research that could have implications for predicting climate change and the search for extraterrestrial life.

“This paper aims to inform the Earth science community about where research should go next,” said Christopher Tino, Ph.D., UCR, and first author of the study at the time it was conducted.

Many studies have examined signs of early life preserved in ancient rocks, but this paper was recently published in the journal Nature. Nature Studies Microbiology It combines these data with genomic studies of modern organisms and recent discoveries in the evolution of the chemistry of the first oceans, atmospheres, and continents.

The paper shows how the earliest forms of life on Earth—microbes such as O2-producing bacteria and methane-producing archaea—shaped and shaped changes in the oceans, continents and atmosphere.

“The main message of all of this is that you can’t look at any one part of the record in isolation,” said Timothy Lyons, UCR Distinguished Professor of Biogeochemistry and co-author. “This is one of the first times that research in these areas has been brought together completely enough to reveal a common narrative.”

Bringing together experts in biology, geology, geochemistry and genomics, the paper details the journey of early life forms from their first appearance to their rise to ecological importance. As their numbers grew, microbes began to affect the surrounding world by producing oxygen, for example through photosynthesis.

According to Tino, now a doctoral student at the University of Calgary, the results in each area often “agree surprisingly.”

Evolution of microbial life and environmental impact

Specifically, the study tracks how microbial life consumes, transforms, and distributes essential nutrients such as nitrogen, iron, manganese, sulfur, and methane. These biological pathways evolved as the Earth’s surface changed dramatically with and sometimes because of new life. Continents emerged, the sun grew brighter, and the world became saturated with oxygen.

Because the evolution of new biological pathways affects these elemental cycles, their trajectories tell us when the first life forms emerged, how they affected and responded to the environment, and when they formed global ecological footprints.

Rocks that are billions of years old often lack the visible fossils needed to tell the full story, but this study pieced together the chemical composition of these rocks and the genomes of living relatives to build a complete picture of ancient life.

“Essentially, we’re identifying Earth’s first flirtation with microbes that could change the global environment,” said Lyons, who is also director of the Center for Alternative Earth Astrobiology in the Department of Earth and Planetary Sciences. “You need to understand the whole picture to fully understand the who, what, when and where of microbes evolved from simple existence to significant environmental impact.”

Many scientists assume that life quickly became prolific once it emerged on Earth. Only by combining decades of interdisciplinary research, as Lyons, Tino, and their colleagues have done in this paper, will scientists be able to see the difference between the sheer presence and dominance of certain microbes. Often, the rise from existence to prominence took hundreds of millions of years.

“Microbes that first lived in tight spaces have evolved into big kids,” Lyons said.

It all boils down to the fundamental question that keeps the UCR team up at night: Where do we come from?

But the answers from this research also have more practical applications, including understanding how life and the environment might respond to climate change, both in the near term and in the distant future.

The research could also help in the search for life on other planets. “If we find evidence of life beyond Earth, it will most likely be based on microbial processes and products such as methane and O2,” Tino said.

“We are motivated to serve NASA’s mission, including helping understand how exoplanets could support life,” Lyons said.