Abstract Detail

Poster Session

Cheeke, Tanya E [1], Phillips, Richard P [1], Fransson, Petra [2].

Mycelial production and turnover differ in temperate hardwood forests dominated by arbuscular mycorrhizal trees versus ectomycorrhizal trees.

Mycorrhizal fungi play a critical role in nutrient cycling, but their effects on belowground carbon (C) cycling are poorly understood. Mycorrhizal mycelia are the dominant pathway through which C from trees enters the soil organic matter pool. However, mycorrhizal mycelium can also accelerate soil organic matter decomposition through the release of extracellular enzymes. We investigated mycorrhizal mycelia production and turnover across a nutrient economy gradient in three temperate hardwood forests in central Indiana. The nutrient economy gradient is driven, in part, by differences in the abundance of tree species colonized by ectomycorrhizal fungi (ECM) and arbuscular mycorrhizal (AM) fungi.  Hyphal ingrowth bags were harvested sequentially over the course of a growing season, and free and total ergosterol concentrations were quantified to estimate active and total fungal biomass. We found that fungal biomass (as determined by ergosterol concentration) increased with increasing dominance of ECM-associated trees, and that there was a stratification of fungal biomass along the soil profile, with the highest levels of ergosterol being present in the 0-5 cm fraction of bulk soil followed by lower levels of ergosterol deeper in the soil profile. Data from this multi-year experiment will be used to develop a predictive framework for examining how trees and their microbial associates influence C and nutrient cycling in temperate forests. Understanding the role of mycelial production and turnover on belowground C storage is critical for predicting how forest ecosystems might respond to environmental perturbations such as climate change.

1 - Indiana University, Department of Biology, 1001 E Third St, Bloomington, IN, 47405, USA
2 - Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology, P. O. Box 7026, Uppsala, SE-750 07, Sweden

Keywords:
fungal ecology
carbon dynamics
forest ecology.

Presentation Type: Offered Paper - Poster
Session: P7
Location: Lincoln Room/Kellogg Hotel and Conference Center
Date: Monday, June 9th, 2014
Time: 8:00 PM
Number: P7010
Abstract ID:135
Candidate for Awards:Graduate Student Poster Presentation Award