Community 3 1. Guild 1: methanogenic bacteria(CO2-CH4) homoacetogenic bacteria(CO2- acetate) 2. Guild 2: sulfate-reducing bacteria(S0,2- +H2S) sulfur-reducing bacteria(S→H 3. Guild 3: denitrifying bacteria(NO, N2) ferric iron-reducing bacteria (Fe→Fe2) 4. Guild 4: fermentative bacteria(fermenting sugars amino and fatty acids, Community 3 and so on) SedimentsCommunity 3