ProteobacteriaArchaeaRNA, Ribosomal, 16SPhylogenyBacteriaDNA, RibosomalDNA, ArchaealAlphaproteobacteriaMolecular Sequence DataGenes, ArchaealArchaeal ProteinsRNA, ArchaealSequence Analysis, DNAGammaproteobacteriaDNA, BacterialBetaproteobacteriaSeawaterCrenarchaeotaMetagenomeWater MicrobiologyGenome, ArchaealEpsilonproteobacteriaSoil MicrobiologyGenes, rRNARNA, BacterialGeologic SedimentsMethaneBiodiversityActinobacteriaFusobacteriaDeltaproteobacteriaEcosystemBacterial ProteinsBase SequenceBiotaRhodobacterGene Expression Regulation, ArchaealNitrosomonasHaloferax volcaniiGenome, BacterialFresh WaterEvolution, MolecularBradyrhizobiaceaeMetagenomicsGram-Negative Facultatively Anaerobic RodsSewageBacteroidetesGenes, BacterialPlanktonCytophagaMicrobiotaSulfonium CompoundsMethanococcusAmmoniaBase CompositionBacteria, AerobicBiodegradation, EnvironmentalGene Transfer, HorizontalSulfolobusAmino Acid SequenceGram-Negative Aerobic Rods and CocciGram-Negative BacteriaThiotrichaceaeEnvironmental MicrobiologyGram-Negative Aerobic BacteriaMethanobacteriaceaeSequence AlignmentBioreactorsOxidoreductasesOxidation-ReductionSulfur-Reducing BacteriaSymbiosisGallionellaceaeBacterial Physiological PhenomenaMoritellaEukaryotaPolymerase Chain ReactionEuryarchaeotaDenaturing Gradient Gel ElectrophoresisMethanosarcinaArctic RegionsAnaerobiosisProkaryotic CellsNitrificationSequence Homology, Amino AcidGastrointestinal TractSequence Homology, Nucleic AcidMicrobial ConsortiaGram-Negative Chemolithotrophic BacteriaMarine BiologyNitrogen FixationAerobiosisMethanobacteriumPseudomonadaceaeDesulfurococcaceaeCluster AnalysisSpecies SpecificityPacific OceanMethanosarcinalesWaste Disposal, Fluid