Aquatic hyphomycetes show pollution-induced community tolerance in nitrogen enrichment experiment

Freshwater ecosystems face significant threats worldwide, particularly from land use changes that impact biodiversity and ecosystem functions in rivers and streams. Essential elements such as carbon, nitrogen, and phosphorus play crucial roles in these ecosystems by directly influencing microbial activity and organic matter processing. This study examines the impact of increased nitrogen levels on the diversity and reproduction of aquatic hyphomycetes associated with decomposing leaf litter in the Chocancharava River, Córdoba, Argentina. Through a microcosm experiment, the objectives were to identify colonizing fungal species, analyze structural variables of the fungal community, and assess variations in sporulation rates and leaf litter decomposition rates of Salix sp. Contrary to expectations, no significant differences in fungal community structure were observed between the control and nutrient-enriched treatments. The increased nitrogen concentrations did not enhance fungal community growth, suggesting possible adaptation to chemical stressors consistent with the concept of pollution-induced community tolerance. These findings provide valuable insights into aquatic ecosystem resilience to nutrient enrichment, highlighting the importance of understanding microbial responses for effective ecosystem management.