Assessing freshwater fungi productivity and community composition to understand leaf litter decomposition rates in a mesocosm experiment

• Grant number: 25/04986-5
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: August 23, 2025
• End date: November 20, 2025
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Gustavo Quevedo Romero
• Grantee: Marcela Lamas Cosenza
• Supervisor: Andreas Bruder
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Scuola Universitaria Professionale Della Svizzera Italiana, Mendrisio, Switzerland
• Associated to the scholarship: 24/17069-8 - How different climate change and land use scenarios affects microorganisms diversity and freshwater ecosystem functioning: a mesocosms experiment, BP.MS

Abstract

Fungi are key organisms for freshwater ecosystems, playing an important role in the leaf litter decomposition process. Changes in fungi biodiversity and productivity affect litter decomposition rates and contribute to secondary production and higher trophic levels. The role of fungi in neotropical freshwater ecosystems is still understudied, limiting the information regarding fungal responses to environmental variables and multiple anthropogenic stressors. Thus, the goal of this project (which is a crucial part of my Masters project) is to determine fungal biomass and community composition in leaf litter retrieved from a 170-day mesocosms experiment. In the experiment, I tested the effects of riparian vegetation reduction, warming and nutrient input on several interlinked ecosystem responses. In my research internship, I will focus on two key elements of my Masters project. First, I will learn and apply techniques to quantify fungal biomass with the ergosterol assay - it uses high-performance liquid chromatography (HPLC) to quantify the concentration of ergosterol in the leaf matrix. Ergosterol is a lipid of the cell membrane of higher fungi (which are also the one driving the decomposition process) and can be calculated into fungal biomass because its concentration is relatively constant between different species and environmental conditions. Second, I will analyze ITS genomic data from the same leaves, to assess fungi community composition (metabarcoding). ITS is the molecular barcode most suitable for the identification of higher fungi. This will help elucidate the respective roles of different fungal taxa in the decomposition process. Our results will improve the understanding of the sensitivity of fungi to multiple stressors and provide relevant insights for conservation and management measures in neotropical freshwater ecosystems.