• Publications
  • Influence
Isotopic evidence for biological nitrogen fixation by molybdenum-nitrogenase from 3.2 Gyr
TLDR
This work presents nitrogen isotope ratios from marine and fluvial sedimentary rocks of prehnite–pumpellyite to greenschist metamorphic grade and suggests that molybdenum was bioavailable in the mid-Archaean ocean long before the Great Oxidation Event.
Contributions to late Archaean sulphur cycling by life on land
Life on land dates back at least 2.7 billion years, but the effects of this early terrestrial biosphere on biogeochemical cycling are poorly constrained. Marine sulphur data and geochemical modelling
Selenium isotopes support free O2 in the latest Archean
Selenium (Se) undergoes redox transformations and isotopic fractionations at relatively high redox potentials and could therefore provide insight into changes in oceanic and atmospheric O2 levels
Modeling pN2 through Geological Time: Implications for Planetary Climates and Atmospheric Biosignatures.
TLDR
The results support the idea that an exoplanetary atmosphere rich in both N2 and O2 is a signature of an oxygen-producing biosphere and suggest that life appears to be necessary for significant atmospheric pN2 swings on Earth-like planets.
Biomass recycling and Earth’s early phosphorus cycle
TLDR
It is proposed that the size of the marine phosphorus reservoir was instead constrained by muted liberation of phosphorus during the remineralization of biomass, contributing to the delayed rise of atmospheric oxygen.
Selenium isotopes record extensive marine suboxia during the Great Oxidation Event
Significance Oxygen is essential for eukaryotic life. The geologic record of early Earth contains abundant evidence of low oxygen levels, and accordingly, a lack of eukaryote fossils. The rise of
...
...