Comparative Analysis of Bioaerosol and Waterborne Microbial Communities in Alpine Lakes
This project aims to compare the microbial communities present in bioaerosols and water samples from alpine lakes, providing insights into the sources, dispersal mechanisms, and ecological roles of microbes in these unique ecosystems. Alpine lakes are sensitive indicators of environmental change due to their isolation, pristine conditions, and rapid response to climatic fluctuations. Microbes play critical roles in these ecosystems, influencing nutrient cycling, organic matter decomposition, and primary production. However, the interactions between airborne microbial communities and those in aquatic environments remain poorly understood. This project explores this under-studied relationship, which is crucial for predicting the impact of climate change and pollution on sensitive alpine environments.
The candidate will engage in comprehensive fieldwork, collecting bioaerosol samples using different air samplers and water samples from various depths and locations within alpine lakes. You will learn and apply advanced laboratory techniques, including DNA extraction, purification, and 16S rRNA gene sequencing using next-generation sequencing platforms to characterize bacterial communities. Quantitative PCR (qPCR) will be used to quantify the microbial biomass, while tools such as QIIME2 and R Studio will be used to process sequencing data and statistical and multivariate analyses will be applied to compare microbial diversity and composition, identifying factors influencing community structure and function. Fieldwork will involve multiple trips to selected alpine lakes, capturing temporal variations in microbial communities and fostering skills in environmental sampling, logistical planning, and sample preservation.
This project will contribute to a deeper understanding of microbial life in alpine ecosystems, linking atmospheric and aquatic microbial communities and offering new perspectives on microbial dispersal and ecological connectivity in mountainous regions. The research will inform predictions on how alpine microbial ecosystems might respond to future environmental changes and aid in developing strategies to preserve these fragile environments. By engaging in this project, the candidate will develop a diverse skill set in molecular biology, microbiology, field research, and data analysis, preparing them for a successful career in environmental microbiology and microbial ecology.
Contact information: Dr. Anna Carratalà ([email protected])
Nanostructured materials for multi-viral filtration
Human activities and climate change are increasing the contamination risk posed by water-borne viruses to global water systems1. Conventional approaches for viral filtration from water, such as disinfection (e.g. via chlorination), often require centralized infrastructure with expert monitoring2. Unfortunately, these technical strategies are often inaccessible to underdeveloped or remote communities, and lack the flexibility to deal with emergencies such as natural disasters3. In these instances, simplified approaches such as gravity-based depth filtration are better suited to obtain clean drinking water4.
Depth filtration systems consist of a porous filtration medium to adsorb contaminants from the filtrate, differing from standard filtration techniques which utilize e.g. size exclusion to remove suspended materials at the membrane surface only. A common example of such filters are packed beds of granulated materials, such as the activated carbon found in Brita® water filters. In comparison to other membrane-based technologies, pressure drops are much lower for depth filtration, resulting in reduced energy requirements (if any) and thus lower costs. The driving pressure can be applied via an external pump, or even via the use of hydrostatic pressure, i.e. from the weight of the water to be filtered.
Despite their advantages, state-of-the-art depth filters still have some intrinsic limitations which are yet to be overcome. Viruses are particularly problematic for traditional depth filters due to their small size, requiring highly adsorbent materials which are also capable of processing large flow rates. High surface area nanostructured materials present a promising solution to this challenge5, however, they are typically characterized by high fabrication costs, ruling out their real-world application. Furthermore, metal ion leaching from such nanomaterials poses significant health risks6 which are often not addressed in the academic literature.
At the High Performance Ceramics lab at Empa, we have performed preliminary tests identifying a prom-ising high surface area material for the removal of viruses and bacteria from water. The nanostructures are obtained from cheap and commercially available raw materials, with intrinsic beneficial properties for water-filtration. In collaboration with OST (Rapperswil), we are now investigating the viability of this material as the basis for an advanced filter system for multi-viral filtration (ARMFUL), with the goal of commercialization in the medium-term.
We are looking for a motivated MSc. thesis student to take part in this exciting multi-disciplinary project encompassing aspects of: microbiology, chemical synthesis, colloidal science, and chemical engineering, to help develop and test filters obtained with nanomaterials. You will work under the daily supervision of a Postdoc to optimize the synthesis of the nanostructured material, help design the filtration system, and investigate the range of possible operating conditions for virus filtration. This project is the culmination of a long-standing research line at Empa, and we expect that your work will form part of a future publication. Subject to the performance of the final filtration system, we hope to develop a spin-off if the product is deemed commercially viable.
If you have a curious mind, an appetite for challenges, and the willingness to learn new skills on the job, we would love to hear from you! For further information, please contact Max Bailey ([email protected])
[1] Hunter, P. R. (2003). Journal of applied microbiology, 94(s1), 37-46.
[2] Hashmi, I., Farooq, S., & Qaiser, S. (2009). Environmental monitoring and assessment, 158,
393-403.
[3] Frechen, F. B., et al. (2011). Water Science and Technology: Water Supply, 11(1), 39-44.
[4] Pronk, W., et al. (2019). Water research, 149, 553-565.
[5] Savage, N., & Diallo, M. S. (2005). Journal of Nanoparticle research, 7, 331-342.
Production of metabolic water by bacteria as a strategy for environmental adaptation in alpine and polar environments
Water is the most essential element which directly or indirectly sustains all life forms on Earth. Many animals can only survive for few days in the absence of water. Bacteria, on the other side, can inhabit the driest environments in the planet, such as deserts and glacier ice sheets. In these ecosystems, the presence of liquid water is extremely scarce and water is thus one of the most important limiting factor for biodiversity. Nevertheless, scientists have shown that a wide diversity of bacteria communities can thrive in these extreme ecosystems. But, what adaptation mechanisms allow microbial life in the quasi absence of liquid water?
Bacteria (among other organisms) are capable of producing water as a by-product of their metabolism. This water is known as metabolic water. For years, metabolic water was believed to be of minor quantitative importance as water may potentially freely diffuse through cell membranes. However, recent studies have determined the proportion of metabolic water in the cytoplasm of bacteria by isotope probing. Recent results show that metabolic water can account for 40 to 70% of the water found in the cytoplasm of bacteria in their exponential growth phase. This interesting finding suggests that the production of metabolic water can be much more important for bacteria cells than previously thought.
In this master project, you will contribute to create a collection of bacteria isolates from polar and alpine environments and to quantitatively determine the production of metabolic water in the cultured bacteria under different environmental stressors such as UV radiation, heat and desiccation. The outcomes of this project will allow us to better understand the role of metabolic water production in the adaptation of polar and alpine bacteria to extreme environmental conditions and, secondarily, to determine whether it would be viable to scale-up the production of water in bioreactors so bacteria metabolic water can be used in the future to develop new biotechnological applications, for example as drinking water in space stations or during drought-related emergency situations. Contact us if you are interested!
Contact information: Dr. Anna Carratalà ([email protected])