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Harvard Forest Symposium Abstract 2012

  • Title: Fungal Hyphal Respiration Shows Potential Signs of Acclimation at the Prospect Hill and Barre Woods Soil Warming Experiments
  • Primary Author: Carley Kratz (Michigan Technological University)
  • Additional Authors: Andrew Burton (Michigan Technological University)
  • Abstract:

    This study measures the ways in which fungal hyphae change physiologically in response to increases in soil temperature. Both the Prospect Hill and Barre Woods soil warming experiments were sampled during the 2011 field season. Hyphal in-growth bags were used to separate fungal hyphae from other soil organisms. The in-growth bags are made of a nylon mesh with a pore size of 55 µm and filled with clean sand. The small pore size discourages the growth of roots into the hyphal in-growth bags. The sand lacks nutrients or organic matter, so few bacteria colonize the in-growth bags. Hyphal in-growth bags were placed 5 cm below the soil surface and incubated there for 2 months from July to September. The in-growth bags were harvested and respiration was immediately measured using a LiCor 8100 infrared gas analyzer with a custom built PVC chamber. Fungal hyphal biomass was estimated using the filter-floatation method to remove hyphae from the in-growth bags. Biomass specific respiration was significantly lower in heated versus control plots at both LTER warming experiments (See Figure 1). At Barre Woods, fungal hyphal biomass was significantly higher in the control versus heated plots (p=0.003). There were no significant differences in the amount of hyphal biomass in the heated and control plots at Prospect Hill. These results suggest that, in general, hyphal respiration decreases under long-term soil warming. The mechanisms behind this reduction in biomass specific respiration remain unclear. It is possible that the respiration of fungi growing in heated treatments has become acclimated to higher temperatures due to a physiological homeostasis response. It is also possible that other nutrients and resources may limit the growth of fungal hyphae in the warmed plots, but not in the control plots. A decrease in available labile nutrients or carbon sources may occur with long-term soil warming. Another possibility is that biomass specific respiration is lower in the heated versus control plots because soil moisture is lower in heated plots due to increased evapotranspiration

  • Research Category: Large Experiments and Permanent Plot Studies

  • Figures:
    • HarvardForest-Kratz-2012Figure.pdf