I am interested in how our planet has evolved as a system over time. I primarily use geochemical and isotopic tracers to study the composition of past oceans and atmosphere and am fascinated by how the surface environment has 'co-evolved' with life through crucial junctures in Earth history. I work particularly on rocks deposited between about 1000 and 500 million years ago, when complex multicellular life first began to dominate ecosystems. My research group develops proxies to trace biogeochemical fluxes and related feedbacks that govern oxygen, carbon dioxide and nutrient budgets on Earth. During the Neoproterozoic, the Earth experienced profound climate change, deep ocean oxygenation and tectonic upheaval, events that are closely related to the biological revolutions which led the way to our modern Earth system. Unravelling the relative significance and timing of these mutual interactions is a key goal of our research. Geochemistry can also be applied to environmental problems and I have worked on this at times, e.g. applying coral geochemistry to constrain how the introduction of livestock in Australia caused massive soil erosion, already within just a year of their arrival. My interests in sedimentary phosphorite have led to side-projects on land remediation and sustainable resources (rare earth elements and phosphates for fertilizer).