Dr Kristen Karsh
Kristen’s current research tests potential molecular and chemical proxies of bacterial nitrogen cycling. Through mechanistic laboratory studies and in situ sampling, she examines correlations between process rates (e.g. denitrification), and bacterial community composition, functional gene abundance, organic carbon bioavailability, and isotopic fractionation in organic nitrogen and dissolved nitrate. Kristen collaborates with biogeochemical modellers to improve the functioning of bacterial nitrogen processes in CSIRO’s core ecosystem models and to integrate the environomic and isotopic measures she and others develop.
Kristen (re-)joined CSIRO in March 2018. She has a BSc degree in geology & geophysics from Yale University, a MSc in marine and Antarctic studies from the University of Tasmania, and a PhD in biogeochemistry awarded through a joint program between the University of Tasmania and Princeton University. From her base at CSIRO during her PhD, Kristen researched how environmental conditions and the physiological state of microalgae influenced fractionation of the nitrogen and oxygen isotopes of nitrate. The research both improved interpretation of nitrate isotopes in the Southern Ocean and other marine environments, and revealed an unexpected role for nitrate within the microalgal cell.