Positions

Overview

  • I received a Bachelor's degree in Chemistry from Yale University in 1987 and a Masters (1994) and PhD (1997) in Environmental Sciences from the University of Virginia. I had a post-doctoral position from 1997-1999 at the US Environmental Protection Agency in Corvallis, Oregon, and a second post-doctoral position from 2000-2001 at the Max Planck Institute for Biogeochemistry in Jena, Germany, before joining the Institute.

    The main focus of my work has been using stable isotopes at natural abundance levels to understand carbon and nitrogen cycling in forest ecosystems. I am particularly interested in understanding the importance of mycorrhizal fungi in forests and in tundra environments, both as a carbon sink and as a source for nitrogen. Mycorrhizal fungi are ubiquitous root symbionts that supply the majority of nutrients to forest vegetation, protect tree roots against pathogens, and filter out potentially toxic metals such as aluminum. Mycorrhizal fungi appear heavily affected by atmospheric nitrogen deposition in Europe, and we suspect that the same processes are starting to operate in the northeastern US, with possibly deleterious consequences for forest health, including the uptake of other important nutrients such as calcium. We use culture studies, isotopic tracers, natural abundance measurements, and computer modeling to understand the role of mycorrhizal fungi in terrestrial ecosystems.

    Other work has included using isotopic measurements to understand diets of small rodents, marsupials, bears, and kiwi, assessing the carbon sources of 400-million-year old fungi (that happened to be 6 meters tall), and applying tracer isotopes of glucose to understand the main metabolic fluxes during lipid biosynthesis in cultured fungi. More information about my past and present research can be found at http://www.isotope.unh.edu/research.shtml.
  • Publications

    Academic Article

    Year Title
    2017 Stable isotopes and radiocarbon assess variable importance of plants and fungi in diets of arctic ground squirrelsArctic, Antarctic, and Alpine Research.  49:487-500. 2017
    2017 Long-term carbon and nitrogen dynamics at SPRUCE revealed through stable isotopes in peat profilesBiogeosciences.  14:2481-2494. 2017
    2017 Dietary protein content and tissue type control 13 C discrimination in mammals: an analytical approach.Rapid Communications in Mass Spectrometry.  31:639-648. 2017
    2017 Increased C-3 productivity in Midwestern lawns since 1982 revealed by carbon isotopes in Amanita thiersiiJOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES.  122:280-288. 2017
    2016 Isotopic evidence indicates saprotrophy in post-fire Morchella in Oregon and Alaska.Mycologia.  108:638-645. 2016
    2016 The ectomycorrhizal status of a tropical black bolete, Phlebopus portentosus, assessed using mycorrhizal synthesis and isotopic analysis.Mycorrhiza.  26:333-343. 2016
    2016 Isotopic Analysis of Sporocarp Protein and Structural Material Improves Resolution of Fungal Carbon Sources.Frontiers in Microbiology.  7:1994. 2016
    2015 Mycorrhizal roots in a temperate forest take up organic nitrogen from C-13- and N-15-labeled organic matterPlant and Soil.  397:303-315. 2015
    2015 Redefining fine roots improves understanding of below-ground contributions to terrestrial biosphere processes.New Phytologist.  207:505-518. 2015
    2015 Exploring the phylogenetic affiliations and the trophic mode of Sedecula pulvinata (Sedeculaceae).Mycologia.  107:688-696. 2015
    2015 Fish Productivity and Trophic Transfer in Created and Naturally Occurring Salt Marsh HabitatEstuaries Chesapeake Science Estuaries and Coasts.  38:1233-1250. 2015
    2015 Convergence of soil nitrogen isotopes across global climate gradients.Scientific Reports.  5:8280. 2015
    2014 Fungal carbon sources in a pine forest: evidence from a C-13-labeled global change experimentFungal Ecology.  10:91-100. 2014
    2014 Fungi, ecosystems and global changeFungal Ecology.  10:1-2. 2014
    2014 Fungal functioning in a pine forest: evidence from a ¹⁵N-labeled global change experiment.New Phytologist.  201:1431-1439. 2014
    2013 Radiocarbon evidence for the mining of organic nitrogen from soil by mycorrhizal fungiBiogeochemistry.  114:381-389. 2013
    2013 Microbes in nature are limited by carbon and energy: the starving-survival lifestyle in soil and consequences for estimating microbial rates.Frontiers in Microbiology.  4:324. 2013
    2012 Nitrogen isotopes link mycorrhizal fungi and plants to nitrogen dynamics.New Phytologist.  196:367-382. 2012
    2012 Controls of isotopic patterns in saprotrophic and ectomycorrhizal fungiSoil Biology and Biochemistry.  48:60-68. 2012
    2012 Long- and short-term precipitation effects on soil CO2 efflux and total belowground carbon allocationAgricultural and Forest Meteorology.  156:54-64. 2012
    2012 Amino acid cycling in plankton and soil microbes studied with radioisotopes: measured amino acids in soil do not reflect bioavailabilityBiogeochemistry.  107:339-360. 2012
    2011 Conservation of ectomycorrhizal fungi: exploring the linkages between functional and taxonomic responses to anthropogenic N depositionFungal Ecology.  4:174-183. 2011
    2011 Conservation of biotrophy in Hygrophoraceae inferred from combined stable isotope and phylogenetic analyses.Mycologia.  103:280-290. 2011
    2010 Carbon sources for the Palaeozoic giant fungus Prototaxites inferred from modern analogues.Proceedings of the Royal Society B: Biological Sciences.  277:2149-2156. 2010
    2010 Nitrogen isotopes in ectomycorrhizal sporocarps correspond to belowground exploration typesPlant and Soil.  327:71-83. 2010
    2009 LINKING ECTOMYCORRHIZAL SPECIES COMPOSITION TO BELOWGROUND FUNCTION AND EXPLORATION TYPES.Journal of Nematology.  41:339-340. 2009
    2009 Tracing metabolic pathways of lipid biosynthesis in ectomycorrhizal fungi from position-specific 13C-labelling in glucose.Environmental Microbiology.  11:3087-3095. 2009
    2009 Controls of nitrogen isotope patterns in soil profilesBiogeochemistry.  95:355-371. 2009
    2009 Nutrient allocations and metabolism in two collembolans with contrasting reproduction and growth strategiesFunctional Ecology.  23:745-755. 2009
    2009 Global patterns of foliar nitrogen isotopes and their relationships with climate, mycorrhizal fungi, foliar nutrient concentrations, and nitrogen availability.New Phytologist.  183:980-992. 2009
    2009 Mycorrhizal fungi supply nitrogen to host plants in Arctic tundra and boreal forests: 15N is the key signal.Canadian Journal of Microbiology.  55:84-94. 2009
    2009 Nutrient Supply Rate and Mycorrhizal Colonization Control Patterns of Element Distribution in Ectomycorrhizal PineCommunications in Soil Science and Plant Analysis.  40:3503-3523. 2009
    2008 Nitrogen form, availability, and mycorrhizal colonization affect biomass and nitrogen isotope patterns in Pinus sylvestrisPlant and Soil.  310:121-136. 2008
    2008 Natural abundance of (15)N in nitrogen-limited forests and tundra can estimate nitrogen cycling through mycorrhizal fungi: A reviewEcosystems.  11:815-830. 2008
    2007 C-13 and N-15 in microarthropods reveal little response of Douglas-fir ecosystems to climate changeGlobal Change Biology.  13:1386-1397. 2007
    2007 The ectomycorrhizal status of Calostoma cinnabarinum determined using isotopic, molecular, and morphological methodsCanadian Journal of Botany Botany.  85:385-393. 2007
    2007 Evidence that saprotrophic fungi mobilise carbon and mycorrhizal fungi mobilise nitrogen during litter decomposition.New Phytologist.  173:447-449. 2007
    2006 15N in symbiotic fungi and plants estimates nitrogen and carbon flux rates in Arctic tundra.Ecology.  87:816-822. 2006
    2006 Carbon allocation to ectomycorrhizal fungi correlates with belowground allocation in culture studies.Ecology.  87:563-569. 2006
    2005 Foliar and fungal 15N:14N ratios reflect development of mycorrhizae and nitrogen supply during primary succession: testing analytical models.Oecologia.  146:258-268. 2005
    2004 Nitrogen availability and mycorrhizal colonization influence water use efficiency and carbon isotope patterns in Pinus sylvestrisNew Phytologist.  164:515-525. 2004
    2004 Carbon use, nitrogen use, and isotopic fractionation of ectomycorrhizal and saprotrophic fungi in natural abundance and 13C-labelled cultures.Mycological Research Fungal Biology.  108:725-736. 2004
    2004 Intramolecular, compound-specific, and bulk carbon isotope patterns in C-3 and C-4 plants: a review and synthesis (vol 161, pg 371, 2004)New Phytologist.  162:240-240. 2004
    2004 Intramolecular, compound-specific, and bulk carbon isotope patterns in C-3 and C-4 plants: a review and synthesisNew Phytologist.  161:371-385. 2004
    2004 Isotopic estimates of new carbon inputs into litter and soils in a four-year climate change experiment with Douglas-firPlant and Soil.  259:331-343. 2004
    2003 Patterns of natural N-15 in soils and plants from chemically and organically fertilized uplandsSoil Biology and Biochemistry.  35:1493-1500. 2003
    2003 Carbohydrate use and assimilation by litter and soil fungi assessed by carbon isotopes and BIOLOG (R) assaysSoil Biology and Biochemistry.  35:303-311. 2003
    2003 Nitrogen availability and colonization by mycorrhizal fungi correlate with nitrogen isotope patterns in plantsNew Phytologist.  157:115-126. 2003
    2002 Contributions of current year photosynthate to fine roots estimated using a C-13-depleted CO2 sourcePlant and Soil.  247:233-242. 2002
    2002 Effects of climate change on labile and structural carbon in Douglas-fir needles as estimated by delta C-13 and C-area measurementsGlobal Change Biology.  8:1072-1084. 2002
    2002 Using radiocarbon to determine the mycorrhizal status of fungiNew Phytologist.  156:129-136. 2002
    2002 Ectomycorrhizal fungal taxa differing in response to nitrogen deposition also differ in pure culture organic nitrogen use and natural abundance of nitrogen isotopesNew Phytologist.  154:219-231. 2002
    2001 Foliar nitrogen concentrations and natural abundance of (15)N suggest nitrogen allocation patterns of Douglas-fir and mycorrhizal fungi during development in elevated carbon dioxide concentration and temperature.Tree Physiology.  21:1113-1122. 2001
    2001 Mycorrhizal vs saprotrophic status of fungi: the isotopic evidenceNew Phytologist.  150:601-610. 2001
    2000 Correlations between foliar δ15N and nitrogen concentrations may indicate plant-mycorrhizal interactions.Oecologia.  122:273-283. 2000
    1999 Interpretation of nitrogen isotope signatures using the NIFTE model.Oecologia.  120:405-415. 1999
    1999 Insights into nitrogen and carbon dynamics of ectomycorrhizal and saprotrophic fungi from isotopic evidence.Oecologia.  118:353-360. 1999
    1998 Natural abundance of nitrogen-15 in a forest soilSoil Science Society of America Journal.  62:778-781. 1998

    Conference Proceeding

    Year Title
    1998 Patterns in N dynamics and N isotopes during primary succession in Glacier Bay, AlaskaChemical Geology. 3-11. 1998

    Principal Investigator On

  • Controls Regulating Biological Nitrogen Fixation in Longleaf Pine Ecosystems: The Role of Fire and Military Training  awarded by University of Georgia 2014 - 2018
  • Can Microbial Ecology and Mycorrhizal Functioning Inform Climate Change Models  awarded by Iowa State University 2012 - 2017
  • Quantification of Organic Nitrogen Use in FACE and Culture Experiments  awarded by National Science Foundation (NSF) 2012 - 2016
  • Modeling and Isotopes Link Mycorrhizal Fungi to Soil Carbon and Organic Nitrogen Use  awarded by National Science Foundation (NSF) 2011 - 2016
  • Dissertation Research: Developing Biochemical Tracers of Apatite Weathering by Ectomycorrhizal Fungi  awarded by National Science Foundation (NSF) 2012 - 2013
  • Bullard Fellowship Proposal at Harvard University: The Role of Ectomycorrhizal Fungi in Forest Ecosystems  awarded by Harvard University 2011 - 2012
  • Organic Nitrogen Cycling in Northern Hardwood-Conifer Forests  awarded by National Science Foundation (NSF) 2008 - 2012
  • Does Increased Precipitation Alter Belowground Allocation and Carbon Storage by Fine Roots and Mycorrhizal Fungi in Pine Savannas  awarded by Joseph W. Jones Ecological Research Ctr 2008 - 2011
  • Fungal Life History Strategies and Evolution: Insights from Isotopic Measurements and Phylogenetic Analysis  awarded by National Science Foundation (NSF) 2009 - 2011
  • Relationships between Carbon Allocation to Mycorrhizal Fungi and Organic Nitrogen use in Temperate Forests  awarded by National Science Foundation (NSF) 2006 - 2010
  • Most Arctic Plants Obtain Nitrogen by Symbiosis with Fungi: Development of a Radical Concept Cooperative Project  awarded by National Science Foundation (NSF) 2006 - 2010
  • MRI Isotope Ratio Mass Spectrometer  awarded by National Science Foundation (NSF) 2004 - 2007
  • Mycorrhizal Fungi Nitrogen Availability & Nitrogen Form  awarded by National Science Foundation (NSF) 2003 - 2007
  • New Insights Calcium Cycling Forests Isotopic Measurements  awarded by National Science Foundation (NSF) 2004 - 2006
  • Post-Fire Morels of Oregon and Alaska  awarded by US DA, Department of Agriculture 2004 - 2005
  • Teaching Activities

  • Isotope Geochemistry Taught course 2019
  • Isotope Geochemistry Taught course 2019
  • Isotope Geochemistry Taught course 2017
  • Education And Training

  • B.S. Chemistry, Yale University
  • M.S. Environmental Science, University of Virginia
  • Ph.D. Environmental Science, University of Virginia
  • Full Name

  • Erik Hobbie