Supervisor: dr hab. Kaja Skubała, prof. UJ (kaja.skubala@uj.edu.pl)

Institute of Botany

Background information:

Biological soil crusts (BSCs) form the complex biological-soil mosaic layers on the soil surface composed of photoautotrophic cyanobacteria, heterotrophic bacteria, algae, lichens, mosses, and micro-fungi. The organisms forming BSCs are the first colonizers and important producers in many water-limited ecosystems in arid/semi-arid climates. BSCs are also found in temperate regions where disturbance regimes create conditions supporting colonization of crust-forming organisms [1]. They play a key ecological role in both aboveground and belowground processes, including C and N fixation, soil formation, improving soil fertility and microbial activity, and facilitating vascular plant colonization. The majority of previous investigations focused on BSCs in arid regions, whereas the function and importance of BSCs in initial habitats of temperate climates is poorly known [2]. BSCs are particularly vulnerable to various disturbances that can affect many aspects of their structure and function. Their impact depends on severity, frequency, timing, and climatic conditions during and after the disturbance [3]. There are different types of habitat disturbances including both natural, such as fires or burial by wind, and anthropogenic associated ones with the mechanical disturbance. Given their significant influence on ecosystem processes, understanding how BSCs respond to disturbance regimes is essential for predicting ecological consequences. The study of regeneration of BSCs after disturbance will enable to further understand the mechanism of BSC development in temperate climate and recognize the factors driving this process.

The main question to be addressed in the project:

The project includes the study of the impact of various disturbance regimes, microclimatic and soil conditions on BSCs. Main questions are:

(1) Which factors determine changes in the physiology and biochemistry of BSCs in the early stages of substrate colonization after the disturbance?

(2) How do the type of disturbance and environmental factors determine the ecophysiological performance of BSCs (as a whole functional unit) and its components?

(3) What are the driving factors of the regeneration process of BSCs after the disturbance in a temperate climate?

(4) How can BSCs be used in novel management strategies aimed at conservation and restoration of rare temperate ecosystems?

Information on the methods/description of work:

The candidate will perform the following research tasks: conducting field research, collection of BSC samples, performing measurements of BSC physiological and biochemical parameters, planning and conducting laboratory experiments, comprehensive statistical analysis, writing scientific papers, promotion of obtained results at conferences, collaboration with an international team. The following research methods will be used: physicochemical analyses of soil, determination of photosynthetic pigment concentrations in BSCs, assessment of their photosynthetic activity based on chlorophyll fluorescence, viability assessment by dehydrogenase activity measurements, determination of the oxidative stress level and antioxidant activity, analyses of exopolysaccharide (EPS) concentrations, and soil microbial activity measurements.

Additional information (e.g Special requirements from the student):

The PhD student should have knowledge in the field of ecophysiology and ecotoxicology and practical experience in performing laboratory analyses. Experience in planning research experiments and the ability to use basic software for statistical analyses are welcome. Working time flexibility and regularity as well as very good knowledge of English are required.

Place/name of potential foreign collaborator:

Shubin Lan, Northeast Normal University (China)

References:

[1] Corbin JD, Thiet RK. 2020. Temperate biocrusts: mesic counterparts to their better-known dryland cousins. Front. Ecol. Environ. 18:456–464.

[2] Chowaniec K., Styburski J., Kozioł S., Pisańska Z, Skubała, K. 2024. Dune blowouts as microbial hotspots and the changes of overall microbial activity and photosynthetic biomass along with succession of biological soil crusts. Microb. Ecol. 87, 22.

[3] Belnap J. 2003. The world at your feet: desert biological soil crusts. Front. Ecol. Environ. 1:181–189.