We call our field of research paleo-bio-geo-chemistry. We use elemental and isotopic techniques to study the rock record and reconstruct changes in environmental conditions as well as their impact on the biosphere. We also actively work on developing new geochemical tools for paleo-environmental studies. Below are some areas of current work.

Ocean (de-)oxygenation through Earth history

All eukaryotes require oxygen for respiration. It has thus long been inferred that ocean oxygenation enabled the evolution of eukaryotic life. Despite this first-order understanding, we still lack knowledge of the causal mechanisms of Earth's oxygenation, and of the precise temporal relationships between oxygenation and the emergence of eukaryotes. Additionally, we can glean important information about forthcoming environmental change by studying periods of transient ocean de-oxygenation. Below are some projects that track past ocean oxygen levels using isotope geochemistry.

Nutrient cycling in ancient ecosystems

Nutrients are rate-limiting reactants for biological productivity on our planet. The cycling of macronutrients (C, N, P) in the ocean is strongly impacted by redox conditions (= oxygen availability), and biological productivity itself impacts marine redox conditions. This creates a rich network of feedbacks that we study through a combination of geochemical analyses and biogeochemical modeling.

Analytical and statistical proxy development

New insights into ancient environments often require new geochemical proxies, or new statistical methods to interpret proxy datasets. We work on both of these fronts to develop novel ways of extracting information from Earth's ancient rock record.