MSc and SIE projects

Context:

Alpine soils play a crucial role in supporting local biodiversity and storing carbon, largely due to the slow degradation rates typical of these harsh environments. However, they are particularly vulnerable to climate change. Shifts in temperature and moisture regimes could destabilise this delicate carbon cycling balance, potentially resulting in either the accumulation or loss of soil organic carbon (SOC). Since both the formation and decomposition of SOC are governed by the soil microbiome, a thorough understanding of microbial processes is essential for forecasting changes in carbon cycling within alpine soils. Soil moisture and temperature are key drivers of microbial metabolism, shaping their activity and efficiency. This raises a crucial question: will changing climate conditions drive alpine soils towards a net loss or gain of SOC?

This MSc project aims to investigate how shifts in soil moisture and/or temperature affect the composition and functioning of soil microbial communities across selected field sites in the Swiss Alps.

The specific objectives of this project include:

• Characterising fundamental soil properties, such as texture, elemental composition, pH, and cation exchange capacity, along a gradient of soil moisture conditions.
• Extracting DNA/RNA from soil samples and performing qPCR to quantify the abundance of functional bacterial, archeal, and fungal genes.
• Employing statistical methods to examine the relationships between gene variations, soil moisture, landscape position, and potential moisture/temperature effects.

Knowledge and skills required:

• Broad interest in soil biogeochemistry and microbiology
• Good organisational skills
• Meticulous in laboratory practices
• Reasonable proficiency with written English
• Willingness to participate in field work
• Willingness to participate in the scientific publication process is a plus

Working place: ALPOLE (Sion)

For more information, explore our project on Mechanisms of Soil Organic Carbon Stabilisation in Alpine Soils, and feel free to contact Kristina Bright for further details.

Context:

Soil organic carbon (SOC) is the largest terrestrial carbon reservoir, closely linked to atmospheric CO₂ through gas exchanges, making it crucial for climate mitigation. In (sub)alpine environments, where trees are absent and degradation rates are slow, SOC stores the majority of ecosystem carbon. However, much of this SOC exists in a labile form as particulate organic carbon (POC), which is vulnerable to rapid mineralization under favorable conditions. Understanding the turnover dynamics of SOC is key to predicting the effects of climate change on these vital carbon reservoirs. This MSc project aims to assess the SOC distribution among different soil fractions along a hydrological gradient in Swiss Alpine soils. 

Objectives:

1. Perform density fractionation of soil samples to quantify the different fractions and analyze the total carbon content in each fraction.
2. Characterize soil properties, including texture, total element composition, total nitrogen, and specific surface area.
3. Conduct statistical analysis to evaluate the relationship between the distribution of carbon in soil fractions, soil properties, and environmental conditions.

Knowledge and skills required:

• Broad interest in soil biogeochemistry.
• Good organization skills.
• Meticulous in laboratory practices.
• Reasonable proficiency with written English.
• Willingness to participate in the scientific publication process is a plus.

Working place: ALPOLE (Sion), some punctual analysis might take place in Geopolis (UNIL)

Contact: For further information, check out our project on Mechanisms of soil organic carbon stabilization in mountain soils and contact Bence Dienes for details.

Context: 

Mountain soils above the treeline hold a significant portion of ecosystem carbon, largely due to slow degradation rates in the harsh alpine environment. Additionally, carbon may be protected from microbial breakdown by binding with soil minerals, but the extent of this process remains unclear. This MSc thesis offers a unique opportunity to explore how soil minerals contribute to organic carbon stabilization across a hydrological gradient in selected field sites in the Swiss Alps.

Objectives:

1. Assess mineral-associated organic carbon (MAOC) through sequential selective dissolution of iron and aluminum oxides.
2. Characterize soil properties, including texture, total element composition, total nitrogen, and specific surface area.
3. Perform statistical analysis to determine the relationship between MAOC, soil properties, and environmental conditions.

Knowledge and skills required:

• Broad interest in soil biogeochemistry.
• Good organization skills.
• Meticulous in laboratory practices.
• Reasonable proficiency with written English.
• Willingness to participate in the scientific publication process is a plus.

Working place: ALPOLE (Sion), some punctual analysis might take place in Geopolis (UNIL)

Contact:.

For further information, check out our project on Mechanisms of soil organic carbon stabilization in mountain soils and contact Bence Dienes for details.

Context:

Preserving soil organic carbon (SOC) stocks is essential for mitigating climate change. SOC decomposition is primarily driven by microbial activity, where microbes utilize oxygen as the preferred electron acceptor during decomposition processes. Agricultural practices, particularly tillage, directly influence soil aeration by altering oxygen availability, thus potentially impacting SOC decomposition and stabilization. Despite the apparent significance of this relationship, the connections between soil aeration metrics -such as oxygen levels, pore structure, and redox potential- and SOC decomposition under various tillage practices have not been systematically evaluated in field conditions.

Goals:

This study aims to assess the impact of different tillage practices, specifically conventional and no-till, on greenhouse gas emissions (carbon dioxide, nitrous oxide, and methane) using a long-term tillage experiment at Agroscope-Changins. The project will involve the use of water retention curve techniques to evaluate pore size distribution across different tillage treatments and soil textures. Additionally, training in X-ray µCT will support the 3D reconstruction of soil pore networks, allowing for analysis of pore metrics such as connectivity and tortuosity. The results will link soil aeration metrics with greenhouse gas emissions and SOC stabilization, offering insights into how tillage practices influence SOC dynamics under field conditions.

Knowledge and skills required:

• Interest in soil biogeochemistry.
• Good organisation skills.
• Enthusiasm for field work and soil lab analyses.
• Reasonable proficiency with written English.
• Willingness to participate in the scientific publication process.

Collaboration: This project will be co-supervised by Orly Mendoza ([email protected]), Stephanie Grand ([email protected]) and Meret Aeppli ([email protected])

Working place: Géopolis (UNIL Lausanne)

Context:

Tillage intensity has been widely implicated in promoting the mineralization of soil organic carbon, consequently leading to an increase in atmospheric carbon dioxide concentrations. However, conflicting findings from a limited number of studies exist. Most of the existing research has primarily focused on aggregate turnover, with a lack of a systematic approach to assessing soil organic carbon stabilization in relation to mineralogical properties across various soil types and depths, particularly under different tillage practices.

Goals:

We propose to use existing samples and collect samples from topsoils and subsoils, which exhibit variations in soil mineralogy and are subjected to different tillage practices -namely, conventional, reduced, and non-tillage- in long-term tillage trials conducted in Switzerland, Italy, and Japan. Through the utilization of soil fractionation techniques, routine mineralogical analyses, and nanoscale methodologies, the student will investigate the impact of tillage intensity on soil mineralogy and in turn on soil organic carbon stabilization. Ultimately, we aim to establish a systematic link between soil mineral composition and properties with the stabilization of soil organic carbon.

Knowledge and skills required:

• Broad interest in soil biogeochemistry.
• Good organisation skills.
• Enthusiasm for soil sampling and soil lab analyses.
• Strong base training in mineralogy.
• Reasonable proficiency with written English.
• Willingness to participate in the scientific publication process.

Collaboration: This project will be co-supervised by Orly Mendoza ([email protected]), Stephanie Grand ([email protected]) and Meret Aeppli ([email protected])

Working place: Géopolis (UNIL Lausanne) and ALPOLE (Sion)

Context:

Agricultural systems are under pressure to produce increasing amounts of food for a growing human population while preserving, and ideally enhancing, the capacity of soils to sequester carbon and provide a habitat for biodiversity. To address these challenges, Nestlé in collaboration with SOIL is supporting regenerative agricultural practices. One such practice is the application of non-harmful, cheap organic fertilizers in combination with additives. These combinations of fertilizers and additives have shown promise in laboratory studies, but it remains unknown if these positive effects manifest themselves when fertilizers plus additives are applied under real-world conditions on agricultural farms. This MSc thesis aims to evaluate the effects of organic fertilizers combined with additives on two different farms in Switzerland. The study will involve both fieldwork and laboratory analyses.

Goals:

The objectives of this thesis are to:

1. Conduct greenhouse gas (GHG) measurements from soils on two Swiss farms.
2. Collect and analyze soil samples from both farms, characterizing key properties such as texture, elemental composition, pH, and X-ray fluorescence (XRF).
3. Assess the impact of organic fertilizers and additives on GHG emissions and soil properties, comparing the results with existing data from previous studies.

For further information, contact Camila Morales for details.

Context: 

Soil organic carbon (SOC) is a critical component of soil health, influencing nutrient cycling, soil structure, and climate regulation. Changes in land use, such as converting natural ecosystems to agriculture or reforesting degraded lands, can significantly impact SOC stocks. 

Most existing studies focus on the effect of land use change on SOC without considering that land selection for conversion may be influenced by pre-existing SOC levels, leading to potential biases. Other regional factors, such as climate, Thus, this project aims to explore both the direct impact of land use changes on SOC stocks and the feedback loop where SOC properties influence land use decisions. This project aims to apply data science techniques to analyze large datasets, identify the key predictors of SOC stocks and disentangle the complex interactions between variables such as land use and climate on SOC dynamics.

Objectives:

1. Literature Review and Database Selection: Conduct a literature review on land use impacts on SOC and select the most suitable dataset(s) for analysis 
2. Data Exploration and Cleaning: Conduct exploratory data analysis (EDA) on the ISCN dataset 
3. Feature Selection: Use machine learning techniques to determine the most influential predictors of SOC stocks.
4. Climate Zone Analysis: Investigate how SOC varies across different Köppen-Geiger climate zones, controlling for soil type and land use.
5. Impact of Land Use Changes: Analyze the effects of historical land management practices on SOC stocks 

Required skills:

• Ability to code in Python
• Strong base knowledge of statistics  
• Broad interest in biogeochemistry 
• Reasonable proficiency with written English.
• Willingness to participate in the scientific publication process.

Preferred skills:

• Previous coursework/experience with data analysis and/or machine learning
• Curiosity and enthusiasm for learning 😊

Working place: ALPOLE (Sion) with remote work flexibility (minimum 2 days per week in Sion)

Contact: If you are interested in applying data science principles to the field of soil biogeochemistry, please contact Emma DeFrang for further details.