Medchem Seminar Series - Lucia Fuchslueger, University of Vienna
Tue
8
Apr
Tuesday 8 April, 2025at 15:15 - 16:00
KB.E3.01 (Lilla hörsalen), KBC, and Zoom
Speaker:
Lucia Fuchslueger
Centre of Microbiology and Environmental Systems Science, University of Vienna, Austria
Title:
Microbial adaptations to low phosphorus conditions in tropical forest soils: Implications for carbon cycling
Abstract:
Tropical forests thrive on highly weathered soils characterized by high nitrogen (N) but limited phosphorus (P) availability. While plant P limitation is well recognized, the implications for heterotrophic microbial communities remain less understood. Microbial adaptations to nutrient constraints can have profound effects on organic matter decomposition, nutrient mineralization, and long-term carbon (C) sequestration.
I will present findings from multiple tropical lowland forest sites across the Amazon Basin, examining root and microbial responses to N and P additions and elevated CO₂. Our research assessed microbial biomass, stoichiometry, enzyme activity, respiration, and growth using a novel ¹⁸O-labeled DNA approach.
Our results reveal that in P-poor soils, microbial biomass can store up to 40% of total P, with strong C-P imbalances suggesting microbial P limitation. Interestingly, microbial growth rates peaked at low soil PO₄ availability, while respiration rates remained unaffected. We further observed that P additions increased microbial P content, but not biomass, highlighting the competitive nature of microbes as a significant P sink. Despite this, microbial communities maintained stable C use efficiency under both N and P enrichment.
These findings underscore the critical role of microbial communities in C, N, and P cycling in tropical soils, revealing their ability to store and compete for P and adapt to strong nutrient constraints. Our data challenge assumptions of microbial stoichiometry, emphasizing the need to refine soil and ecosystem models to account for microbial flexibility in nutrient-limited environments.
