Methane Oxidation in Serpentinization Hosted Ecosystems Taylor Walton
![Percent CH 4 Results from Environmental [NH 3] Experiment Control 5 4 3. 5](https://slidetodoc.com/presentation_image_h2/534b17253aeb8ebef05a1fe6bbc0b2f2/image-7.jpg "Percent CH 4 Results from Environmental [NH 3] Experiment Control 5 4 3. 5")
- Slides: 11
Methane Oxidation in Serpentinization. Hosted Ecosystems Taylor Walton Alta Howells, Michelle Santana, Everett Shock
Culture Dependent Approach: Test Predictions from Environmental Observations Geochemistry Environment Predictions Culture Experiments Biology
Serpentinization in the Oman Samail Ophiolite Mixing = Disequilibrium Energy for… CH 4 + 2 O 2 CO 2 + 2 H 2 O Aerobic Methane Oxidation (Methanotrophs)
Energy available, are methanotrophs present? 16 S r. RNA Gene Analysis CH 4 + 2 O 2 CO 2 + 2 H 2 O
Geochemical Drivers on Distribution of Methanotrophs Our Prediction, Competitive Inhibition by NH 3 Presence/absence plot of 16 S r. RNA genes. , 16 S r. RNA gene is not present. , 16 S r. RNA gene present.
Culture Dependent Approach To Test Hypothesis Growth 6 5. 5 5 %CH 4 Inoculate media designed from environmental geochemistry, ~20% O 2, ~5% CH 4 headspace, p. H 11. 4, 34˚C • Vary [NH 3] • Environmental concentration • NH 3 replete • NH 3 deplete 4. 5 4 3. 5 3 Calculate methane oxidation rate Test hypothesis: Compare rate to [NH 3] 2. 5 2 0 5 Days Rate Evaluate growth of methanotrophs • CH 4 consumption • 16 S r. RNA gene analysis NH 3, mm 10 15
Percent CH 4 Results from Environmental [NH 3] Experiment Control 5 4 3. 5 3 2. 5 2 1. 5 1 0. 5 0 0 10 20 30 40 Days 50 60 70 80 Enrichment Percent CH 4 5 4 3 2 1 0 0 10 20 30 40 Days No significant decrease in methane over 72 days
Environment to Enrichment Community Change 16 S r. RNA Gene Sequencing
Populations Selected for and Against Environment to Culture
Early conclusions and future work • Influence of NH 3 methanotroph growth • From these preliminary results, environmental [NH 3] inhibits growth of methanotrophs in culture • Alternatively, methanotrophs could be slow growers, and longer observation is required • Community response Week 1 2 3 4 • Diversity changes • Rhodobacter, as photo-heterotroph greatly enriched • Methanogens still present in the culture 5 • Next steps • Continue monitoring community growth of environment [NH 3] experiment • Continue CH 4 measurements • 16 S r. RNA gene sequencing on all time points • Run replete/deplete NH 3 experiments
Acknowledgements • ASU/NASA Space Grant • GEOPIG research group • Alta Howells, Michelle Santana, Everett shock • Rock Powered Life
