The discovery of a new single-cell family of microbes in Yellowstone National Park’s spring waters could paint a clearer picture of how life on Earth originated, and how iron played an important part in the evolution of our planet’s earliest life forms.
In a study published earlier this week in the journal Nature Microbiology, a team of researchers from Montana State University detailed how they discovered a new lineage of single-cell microbes from the archaea domain living in Yellowstone’s iron oxide-rich thermal springs, where conditions are said to be similar to those in Earth’s early years.
As iron oxide is one of the key chemical ingredients found on Mars’ surface, the researchers named the lineage Marsarchaeota, also noting that there are two subgroups within it that both thrive in the springs’ acidic water. One of these subgroups lives where the water reaches temperatures of over 122 degrees Fahrenheit, while the other can be found in waters with temperature ranges over 140 to 176 degrees. According to Science Daily, the water where these microbes thrive in is “about as acidic as grapefruit juice.”
“The broad distribution of Marsarchaeota in geothermal, microaerobic iron oxide mats suggests that similar habitat types probably played an important role in the evolution of archaea,” wrote the researchers in a statement.
Explaining the methodologies used by the researchers, Science Alert wrote that the Montana State University team used microscopic analysis and genome sequencing, among other techniques, to learn more about the microbial mats they found in Yellowstone’s thermal springs. The Marsarchaeota were found deep inside these mats, sometimes being so plentiful that they made up over half of all the organisms within a single mat, but what stood out as interesting was how they only required small amounts of oxygen to live.
As explained by Montana State University professor William Inskeep, co-author on the new study, it is possible for microbes in general to produce iron oxide, but not in Marsarchaeota’s case. He speculated that the newly discovered lineage’s role might be related to “reducing iron into a simpler form,” which he believes is noteworthy because iron cycling was an important process during Earth’s early history. The iron oxide produced by Yellowstone’s microbes slow down water streams through the terraces they create, allowing the water to drip on the Marsarchaeota as oxygen is simultaneously captured from the atmosphere, thus providing them with their required oxygen supply.
According to Science Alert, the new microbial discovery at Yellowstone could help scientists figure out how single-cell creatures evolved into far more complex eukaryotes, or multi-celled organisms that include prehistoric and modern plants and animals. More research, however, might be needed in order to determine how microbes can live in such hot and acidic waters.
Although the new study’s biggest implications are related to the processes that life on Earth went through early in our planet’s history, Inskeep commented that the findings discussed in the paper could be applied in a number of other fields, such as industrial and molecular biology.
“Knowing about this new group of archaea provides additional pieces of the puzzle for understanding high-temperature biology,” said Inskeep.