Cyanobacteria are microbes that obtain their energy through photosynthesis and produce oxygen. One of the largest groups of bacteria on Earth, they have been around for more than 2.5 billion years.
Capable of adapting to harsh environments, cyanobacteria have been found in Antarctica, the Mojave Desert, and even the outside of the International Space Station (ISS).
Elmars Krausz of ANU suggested future human colonists on Mars and other solar system worlds could use cyanobacteria adapted to low-light environments to produce oxygen they could breathe and create a biosphere, an area where life could survive.
“This might sound like science fiction, but space agencies and private companies around the world are actively trying to turn this aspiration into reality in the not-too-distant future. Photosynthesis could theoretically be harnessed with these types of organisms to create air for humans to breathe on Mars,” Krausz said.
One particular type of chlorophyll, known as “red” chlorophyll, plays a key role in driving photosynthesis in low-light environments.
“Low-light adapted organisms, such as the cyanobacteria we’ve been studying, can grow under rocks and potentially survive the harsh conditions on the Red Planet,” he noted.
Through their pigments, “red” chlorophylls produce a signature fluorescence that colonizers of other worlds could use to track organisms indigenous to those worlds, stated Jenny Morton of ANU’s Research School of Chemistry.
Using a unique optical spectrometer along with computer modeling, the research team focused on better understanding the role of “red” chlorophylls in the process of photosynthesis.
“This work redefines the minimum energy needed in light to drive photosynthesis,” she added.
In experiments, organisms adapted to low-light environments died when exposed to full sunlight.
“All photosynthetic organisms, such as coral reefs, suffer severe environmental stresses from high temperatures, high light levels, and ultraviolet light, so this research helps scientists to better understand these limits,” Morton explained.
Findings of the study have been published in the journal Science.