From Arctic Environments to the Clouds: Tracing the Origins of ice-forming Microbes

During her PhD studies, Jennie Spicker Schmidt investigated the potential source environments of ice-nucleating active microorganisms across the Arctic and their role in cloud ice formation. Jennie examined microbial communities from soils, glacial runoff, sea ice, and ocean waters to identify where these microorganisms originate. Through her research, she compared microbial community composition and ice-nucleating activity in Arctic source environments and in the atmosphere. She thereby identifies the habitats from which these microorganisms likely originate. Her findings show that terrestrial environments represent an important source of ice-nucleating microorganisms, with additional contributions from sea ice, while marine environments appear more limited under spring conditions. These new findings improve our understanding of how microbial communities across Arctic ecosystems may influence cloud ice formation and climate change.

The PhD study was completed at Department of Biology, Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Monday, 28 September 2026 at 13:00
Place: Building 1632, room 201, AIAS auditorium, Aarhus Institute of Advanced Studies, Aarhus University, Høegh-Guldbergs Gade 6B, 8000 Aarhus.
Title of PhD thesis: Identification and Quantification of Key Reservoirs of Ice-Nucleating Protein-Producing Microorganisms and Their Distribution in the Arctic Habitat
Contact information: Jennie Spicker Schmidt, e-mail: jss@bio.au.dk , tel.: +45 51526608
Members of the assessment committee:
Professor Anders Priemé, Department of Biology, University of Copenhagen, Denmark
CNRS Chaire de Professeur Junior, James Bradley, Mediterranean Institute of Oceanography, Marseille, France
Professor Philip Francis Thomsen (chair), Department of Biology, Aarhus University, Denmark
Main supervisor: Associate professor Tina Šantl-Temkiv, Department of Biology, Aarhus University, Denmark
Co-supervisor: Professor Kai Finster, Department of Biology, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C