Methanogens are supposed to be one of the first life forms that emerged and evolved on early Earth inan environment of high depths and pressure utilizing the chemical energy provided by serpentinization.Serpentinization is a geological process that involves the transformation of low-silica ultramafic rocks,which are present in the lower oceanic crust and upper mantle. During this transformation minerals arereacting with water producing H2. Methanogens that can utilize this H2 to reduce the available CO2(hydrogenotrophs) can thrive in an environment like that, taking advantage of the substrate and energyflow that exists and thrive at these ecosystems. Methanobacterium oryzae is a hydrogenotrophicmethanogen that belongs to the order Methanobacteriales and has been isolated from a rice field inPhilippines. Methanobacterium oryzae strain FPi and a strain (wild strain) similar to that, isolated froman ophiolitic outcrop in an active serpentine site in Chimaera, Antalya, Turkey in 2017, have been usedin this study and have been tested for their survivability and adaptation abilities in different iron and O2concentrations. The two strains were cultivated in mediums with 4 different iron and 2 different O2concentrations for a duration ranging from 9 to 21 weeks. Gas chromatography was used to analyzeweekly gas samples for CH4 and CO2 concentrations that have been used as growth indicators. Scanningelectron microscope pictures have been taken to assess cell presence and contamination as well asidentify mineral precipitates. The results indicate the importance of iron for these species showinglimited or no growth when treated with no iron and enhanced growth at higher concentrations of iron.Furthermore, O2 has hindered or inhibited growth in most of the samples, but lower oxygenconcentrations seem to be tolerated by some specimens throughout the experimental time. Furtherresearch for the detection of the mechanisms behind the survivability of the methanogens with no ironand with oxygen in the medium is needed to further reveal the limits of life and provide moreinformation about the organisms that might have been the first ones that inhabited our planet.