Bacteria, like other organisms in nature, depend on one another for survival, particularly in hostile conditions. The above image shows various bacteria from an environment where there is no oxygen and where microbes make methane . This particular environment is called a methane-producing biomass digester which scientists have set up in the lab to study such organisms.
Methanogens live where there is no oxygen.
Like other microbes that grow without oxygen, methanogens are called anaerobes. The methane produced by this community is used for fuel, a flammable gas known as natural gas used to heat your home. Bacteria often like to live on surfaces. The bacteria and other microbes that live on surfaces make up a slimy surface people generally refer to as slime. Since this slim consists of live creatures, it is called a biofilm.