Name: Natalya Zavina-JamesNatalya

Project Title: “Biological regulation of Earth’s early atmosphere”

Cohort: 2016/17


University of St Andrews

Newcastle University


  • Dr Aubrey Zerkle (University of St Andrews)
  • Dr Paul Savage (University of St Andrews)
  • Dr Neil Grey (Newcastle University)



My interests are broadly within the remit of early earth/life evolution from geochemical and microbiological perspectives. This PhD project focuses on the lead up to the Great Oxidation Event (GOE, ~2.45 billion years ago), during which time Earth’s atmosphere was periodically dominated by a hydrocarbon-rich haze, similar to that of Saturn’s moon Titan. Following the hypothesis that this haze was the result of enhanced biological activity, we plan to utilize the stable isotope geochemistry of nickel and copper in late Archaean sedimentary rocks to investigate how enhanced nutrient input into the oceans may have impacted biogeochemical methane cycling in the oceans. Interpretation of copper in these ancient records will be primarily aided though experiments involving natural populations of methanotrophic bacteria. Specific questions to address include:

  • How do nickel and copper isotopic values in sediments adjacent to modern   hydrothermal systems reflect hydrothermal processes?
  • What are the fractionations in 56Cu produced in laboratory experiments with natural populations of methanotrophic bacteria? Can these provide a proxy for methane oxidation in the associated sediment?
  • How do the trace metal and metal isotope values of late Archeaen sediments vary during periods of haze and during haze free conditions? Do these values reflect enhanced hydrothermal activity and/or enhanced biological methane cycling?


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