Photosynthesis—the harvesting of sunlight to produce energy—is the ultimate driver of virtually all life on the surface of our planet. Most photosynthetic creatures rely on optical light, the kind we see, to energize their biological machinery. Yet some can make use of lower-energy (and invisible to our eyes) infrared light. And in the case of one kind of bacteria—discovered years ago, deep underwater near a hydrothermal vent—this light need not even come from the Sun.
A new study explores the potential for photosynthetic life to persist in such sun-starved conditions. The research aims to shed light, as it were, on how organisms could live off of the dim infrared emissions from hydrothermal vents on alien worlds. Tantalizingly, such vents are theorized to exist beneath the surface of Jupiter's ice-covered, oceanic moon Europa.
"When we became aware of bacteria using infrared light to photosynthesize, we felt very curious about checking the photosynthetic potential with this light because this is one measure of whether life could thrive around hydrothermal vents," said Rolando Cardenas, a physicist at Central University "Marta Abreu" de Las Villas in Santa Clara, Cuba and a coauthor of the paper published in the May issue of Astrophysics and Space Science.
The new findings suggest that photosynthetic life as we know it would struggle to flourish given the small amount of available light in hydrothermal vent environments. But organisms that could make use of lower-energy infrared light might find themselves with plenty to get by on in sunless circumstances.