A quick summary of Archaea. Its a building block of life basically or similar to it apparently. A biologist would know more. You can find plenty online.
Archaea
Archaea are microbes and most live in extreme environments. Those that do are called extremophyles. Other Archaea species are not extremophiles and live in ordinary temperatures and salinities.
When these microscopic organisms were first discovered in 1977, they were considered bacteria. It became apparent however, that they were not when their ribosomal RNA was sequenced. The sequencing showed that they were not closely relationed to the bacteria but were instead more closely related to the eukaryotes.
Archaea are a much different and simpler form of life. They may also be the oldest form of life on Earth. Because they requires neither sunlight for photosynthesis as do plants, nor oxygen as to animals. Archaea absorbs CO2, N2, or H2S and gives off methane gas as a waste product the same way humans breathe in oxygen and breathe out carbon dioxide.
Archaeans may be the only organisms that can live in extreme habitats such as extremely hot thermal vents or hypersaline water. They appear to be extremely abundant in environments that are hostile to all other life forms.