Research area and project description:
The Department of Environmental Science at Aarhus University, Denmark, is offering a PhD position in Arctic microbial ecology, starting 15 January 2027 or earliest possible thereafter.

The overarching aim of this PhD project is to uncover the top-down controls regulating algal and cyanobacterial biomass on the surface of the Greenland Ice Sheet. This is part of a collaboration between Aarhus University and Copenhagen University to identify how viruses, grazers and parasitic fungi influence primary producer populations in supraglacial habitats. The project is funded by the Independent Research Fund Denmark.

The project in a nutshell: Glaciers and ice sheets are increasingly recognized as dynamic ecosystems, home to diverse and metabolically active microbial life. During the summer melt season, eukaryotic algae such as Chlorophyceae and Streptophyta emerge on the snow and on the living skin of ice surfaces of the Greenland Ice Sheet, reducing surface albedo and accelerating melt. Cryoconite holes, which are sediment-filled melt pockets perforating the glacier surfaces, are dominated by cyanobacteria. These phototrophic communities are key players and ecosystem engineers in supraglacial (i.e., the different habitats at the surface of glaciers and ice sheets) biogeochemistry and ice melt. However, while the roles of microbial primary producers have been well documented, the fate of their biomass and the extent to which it is shaped by top-down biological controls remains largely unexplored. 

The role of the PhD student in this project will be particularly focused on the following objectives: 1) the characterization of the abundance, community structure, and grazing activity of protozoan consumers in cryoconite holes and ice surface and 2) the determination of the occurrence, infection dynamics, and ecological effects of chytrid fungi on algal populations in different supraglacial habitats. 

The PhD student will closely collaborate with a postdoc at Copenhagen University who will investigate the role of viruses on microbial mortality on glaciers. Furthermore, to contextualise viral infection, grazing and fungal infection rates, the PhD student will collaborate and have a 3-month international stay at Marseille University to use empirical data to develop a mortality model for supraglacial algae and cyanobacteria, quantifying losses attributable to viral lysis, grazing, and parasitism.

You must upload a project description (not AI generated) about how do you intend to approach the objectives of the project.