Microorganism archaea

Microbiology The study of microorganisms such as fungi, bacteria, algae, archaea, and viruses. [NIH]... 

Archaea Unicellular microorganisms that are structurally similar to prokaryotes but include some metabolic characteristics of eukaryotes. The archaea are genetically distinct from the other two domains. Most extremoptules are members of the archaea. 

Some metals, arsenic and mercury for example, may be volatilized by methylation due to activity of anaerobic microorganisms. Arsenic can be methylated by methanogenic Archaea and fungi to volatile toxic dimethylarsine and trimethylarsine or can be converted to less toxic nonvolatile methanearsonic and dimethylarsinic acids by algae [42]. 

In the still-valid taxonomic model, microorganisms can be classified into the three domains ofeubacteria, archaea, and eukaryotes. The three domains branched off very early in evolution, united by a common ancestor the corresponding picture of the relationships between the domains and kingdoms is termed the universal phylogenetic tree . 

Microorganisms can be classified into three domains eubacteria, archaea, and eukaryotes (fungi). The domain accounting for the most numerous representatives is the eubacteria. Figure 3.1. elucidates the connection between the three domains, which branched off very early in evolution, in all likelihood more than a billion years ago. 

The sulfur- and sulfate-reducing microorganisms represent a large and diverse group that is strictly anaerobic. Most are eubacteria, but several archaea that reduce sulfur have also been described. 

---