Spare a thought for the archaea, a group of microscopic organisms first discovered in the late 1970s. These single-celled organisms are somewhat similar to bacteria, but have several physical differences and tend to be found in extreme environments. Unlike bacteria, these little critters never get the attention they deserve, but to be honest, it’s probably because scientists still know very little about them.
Thankfully, two types of archaea have now finally been isolated by researchers at one of their original discovery sites – Yellowstone National Park, specifically within one of the acidic, geothermal springs there. According to a new study in Nature Communications, these two archaea have a rather curious relationship wherein one of them piggybacks around the environment on the other.
“We discovered and cultured a novel organism from a group of organisms that people have been trying to get for over a decade,” Mircea Podar, head of a team of researchers at Oak Ridge National Laboratory’s Biosciences Division and coordinating author of the study, said in a statement.
The novel specimen, Nanopusillus acidilobi, is just 100 to 300 billionths of a meter in size – stupendously small, and, as it turns out, quite sneaky. Hiding in the concave-shaped depressions of the comparatively sizable members of the archaea genus Acidilobus, N. acidilobi drifts around its broiling, boiling environment, letting its driver do all the work for it.
More precisely, the miniscule archaea attach themselves to the cell membranes of their heat-loving or “thermophilic” Acidilobus hosts. Over time, the little thieves steal all the nutrients they need that are cycling through the host’s cell membrane, which keeps them alive and healthy for as long as the host remains alive.
ORNL explain how they cultured the fragile, demanding extremophiles in their laboratory. Oak Ridge National Laboratory via YouTube
When the host dies, the N. acidilobi can detach from it, drift around for a while, and eventually find a new host to latch on to. No benefit to the host could be seen, which means that this relationship is either commensal, where the host gives up some of its nutrients but isn’t harmed doing so, or ectoparasitic, wherein some harm is done to the host over time. Currently, it’s not clear which is more appropriate, although both are possible depending on the zealousness of the little piggybacker.
- N. acidolobi is compared by the researchers to Nanoarchaeum equitans, another type of marine archaea discovered in a hydrothermal vent off the coast of Iceland back in 2002. Both are thermophilic and survive in very acidic environments, which makes them extremophiles – organisms that do not just survive, but thrive in extreme settings. In fact, it’s thermophiles like these that actually help produce some of the bright colors of Yellowstone’s most famous hot springs.
- Yellowstone's Grand Prismatic Spring, whose bright colors are mostly down to the thermophilic microbes hiding within it. Jim Peaco, Naitonal Park Service