PhD Thesis

PhD Thesis

Effects of river network fragmentation on ecosystem functioning

Supervised by: Prof. Dr. Gabriel Singer (University of Innsbruck UIBK)

Performed as: PhD thesis 

Start: Anytime from May 2020 onwards


Fluvial ecosystems are an important element in the global carbon cycle metabolizing large amounts of terrigenous organic matter (tOM). This contributes to CO2 evasion fluxes that are under continuous reevaluation at the global scale. In contrast, research on the underlying processes is concentrated at the local ecosystem scale. This scale-gap seriously hampers process understanding across scales, limits upscaling accuracy, and reduces our scope of reaction strategies. The ERC Starting Grant Project FLUFLUX (“Fluvial Meta-Ecosystem Functioning: Unravelling Regional Ecological Controls Behind Fluvial Carbon Fluxes”) aims to develop a deeper mechanistic understanding of fluvial carbon fluxes by investigating ecological processes at the intermediate ‘regional’ scale of the ‘fluvial network‘. In particular, respiration of tOM is hypothesized to be an interactive product of organismic diversity and resource diversity, which both follow conspicuous patterns in river networks. From an ecological perspective, river networks may be aptly termed ‘fluvial meta-ecosystems”.


The aim of the open PhD position is to investigate effects of fragmenting a laboratory-based fluvial model meta-ecosystem on patterns of biodiversity, resource diversity and resource use (i.e. respiration). Research tasks include designing the laboratory system in close collaboration with the team, designing and carrying through fragmentation experiments, analysis of microbial biodiversity by molecular biological tools (16SrDNA based metabarcoding), analysis of chemical diversity of dissolved organic matter by high-resolution mass spectrometry (Orbitrap-MS) and measurements of respiration by a smart tracer approach (Resazurin). Ecosystem modeling work could complement the experimental work.


We search for a highly motivated PhD candidate holding a Masters degree in relevant disciplines (Ecology, Limnology, Environmental Sciences, Ecohydrology, Environmental Microbiology, Geochemistry) with experience/motivation in stream/river ecosystem ecology, biodiversity or biogeochemistry. Excellent English is mandatory. Experience in relevant disciplines/methods is advantageous. We offer a 3-year position in an international team starting anytime from May 2020 onwards. Salary will be according to standard remuneration of the Austrian Science Fund (FWF, 30 hours, gross salary approx. 2200/month). The position will be filled upon identification of a strong candidate. UIBK is an equal opportunity employer.


For more information and to apply contact Dr. Gabriel Singer at UIBK ( Submit your application via email including a CV, a brief letter of motivation indicating experience and research interests/ideas, contact details of two referees and copies of pertinent degree certificates.