University of New Hampshire
Mentor: Dr. Andrew Ouimette
Quantifying Carbon Allocation to Mycorrhizal Fungi by Temperate Forest Tree Species Across a Nitrogen Availability Gradient
Terrestrial ecosystems make up the largest carbon pool with a major portion of that being forests. With carbon being a major concern due to global climate change, being able to make accurate models is increasingly important. Studies have shown that trees may allocate up to 50% of their photosynthetically fixed carbon underground; however these values haven’t been accurately quantified and underground carbon allocation has been historically overlooked. Mycorrhizal fungi may be a large portion of underground carbon allocation, as they have a symbiotic relationship with trees where they provide the plant with water and nutrients in return for sugars (carbon). New methods and knowledge will allow us to quantify carbon allocation and fungal biomass. Ergosterol is a biomarker that is the human equivalent of cholesterol for fungi which can be used to measure fungal biomass. Since both free-living and mycorrhizal fungi have ergosterol, a series of open and closed cores located at Bartlett Experimental Forest will separate the amount of ergosterol due to free-living versus mycorrhizal fungi. Using natural nitrogen isotope ratios, the carbon allocation to mycorrhizal fungi by trees could be derived by using a series of equations proposed by Hobbie & Hobbie (2008). This is one of the first studies that will quantify fungal biomass and carbon allocation under a variation of natural settings and compare two different methods to estimate these values.