1 / 16

Brian J. Mailloux Barnard College For the Sloan Deep Carbon Workshop May 16, 2008

Subsurface Microbial Carbon Cycling: Rates and Processes or Recovery and Characterization of a Deep Microbial Ecosystem. Brian J. Mailloux Barnard College For the Sloan Deep Carbon Workshop May 16, 2008. Talk overview. Background Sampling Requirements Use of Carbon isotopes.

alfonso-wiggins
Télécharger la présentation

Brian J. Mailloux Barnard College For the Sloan Deep Carbon Workshop May 16, 2008

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Subsurface Microbial Carbon Cycling: Rates and ProcessesorRecovery and Characterization of a Deep Microbial Ecosystem Brian J. Mailloux Barnard College For the Sloan Deep Carbon Workshop May 16, 2008

  2. Talk overview • Background • Sampling Requirements • Use of Carbon isotopes

  3. State of Knowledge • Examining depths to 120°C • Lower cell numbers at greater depth • Lower diversity at greater depths • Slow • Hard to sample Can we use carbon isotopes to understand rates and turnover times and in the future link to diversity?

  4. Cells/ml or Cells/g 10 102 103 104 105 106 107 108 0.0 1.0 Depth (km) 2.0 3.0 Pfiffner et al. 2006 4.0 State of Knowledge Low Diversity from a 2.825 km deep fault (Lin et al.,)

  5. Requirements of Subsurface SamplingConstraints • CLEAN • Molecular sample constraints? • Sample Size-How large a sample do we need? • Location-Where and how can we sample?

  6. Requirements of Subsurface SamplingMolecular Constraints • PCR • Nanograms of DNA • Metagenomes • 10’s to 100’s of micrograms of DNA • Amounts can be lower with whole genome amplification • Isotopes • 100’s of micrograms of DNA • PLFA’s generally have smaller sample sizes than DNA Knowledge DNA

  7. Requirements of Subsurface SamplingSample Size • 1011 cells. (0.25 mg of DNA) • ROCK • 103 cells/g therefore need 108 grams!! • WATER • 103 cells/ml therefore need 105 liters (10,000L) • At 1 gpm≈2 days • If you have flowing water you can get good samples!

  8. Requirements of Subsurface SamplingLocation • Cores • Access to novel locations • Expensive and size limited • Wells • Access to novel locations • Deep wells can be hard to sample • Mines • Access to the subsurface • Locations limited • Can get clean samples • Can go back repeatedly and run experiments

  9. Carbon Isotopes of DNA • Bangladesh Example • How it could be used in the deep subsurface • 12C=99%, 13C=1%, 14C=1ppt but t1/2=5730 yr • Microarrays

  10. Analyzing 14C of DNA Bangladesh ExampleAtmospheric derived 14C • Sampled ~2000 liters from a 180’ deep well. • Extracted DNA ~150μg (Not trivial!) • 14C DOC ~5700 yr bp • 14C DIC ~6240 yr bp • 14C DNA ~300 yr bp Small, Young, Labile Pool of Organic Carbon! E. Reichert, Senior Thesis

  11. Steady-state Production=Decay. Steady-state Production=Decay. No Production Only Decay after incorporation! How can we use Carbon Isotopes to Understand Subsurface Growth Rates? 14C is generated in situ through decay of U and Th. 14C in DIC, Hydrocarbons, CH4….. 14C in Microbes (DNA)

  12. Imagining an Experiment • Collect 14C and 13C of DNA, DIC, DOC and compound specific electron donors • 14C of DNA should be “older” with a more negative Δ14C • The Δ14C offset should be directly related to the turnover rate (“age”) of the microbes. • Can then directly get to turnover times in the deep subsurface. • Can then use a 14C microarray in a subsurface Beta Cage to relate specific genes to Δ14C

  13. Goals-Need to Link • Isotopes • Geochemistry • Genomics/Proteomics • With good subsurface access

  14. Conclusions ACKNOWLEDGEMENTS T.C. Onstott and collaborators within his lab including: Dylan Chivian, Eric J. Alm, Eoin L. Brodie, David E. Culley, Thomas Gihring, Alla Lapidus, Li-Hung Lin, Steve Lowry, Duane P. Moser, Paul Richardson, Gordon Southam, Greg Wanger,Lisa M. Pratt, Adam P. Arkin, Terry C. Hazen, Fred J. Brockman, Duane Moser Columbia University- Greg Freyer, Martin Stute, Lex van Geen, Elizabeth Reichert LLNL-Bruce Buccholz

More Related