Short communication On the persistence of Cenococcum geophilum ectomycorrhizas and its implications for forest carbon and nutrient cycles Christopher W. Fernandez a, b, * , M. Luke McCormack a, c , Jason M. Hill d , Seth G. Pritchard e , Roger T. Koide f a Intercollege Graduate Degree Program in Ecology, The Pennsylvania State University, USA b Department of Plant Science, The Pennsylvania State University, USA c Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, China d Pennsylvania Cooperative Fish and Wildlife Research Unit, USA e Department of Biology, College of Charleston, USA f Department of Biology, Brigham Young University, USA article info Article history: Received 29 March 2013 Received in revised form 24 May 2013 Accepted 25 May 2013 Available online 10 June 2013 Keywords: Biogeochemistry Cenococcum geophilum C cycling Decomposition Ectomycorrhizal fungi N cycling Root turnover abstract The turnover of ectomycorrhizal (EM) fungal biomass represents an important litter input into forest biogeochemical cycles. Cenococcum geophilum is a nearly ubiquitous and often abundant EM fungus, making the turnover dynamics of this species relevant and important across forest ecosystems. To better understand the turnover dynamics of C. geophilum ectomycorrhizas we examined their persistence using minirhizotron imaging and vitality status using a fluorescein diacetate (FDA) stain and contrasted these results with ectomycorrhizas of other EM fungi. Ectomycorrhizas formed by C. geophilum persisted 4e10 times longer and exhibited contrasting seasonal patterns of vitality compared to ectomycorrhizas of other EM fungi. Together, this suggests that litter resulting from the death of C. geophilum ectomycor- rhizas is relatively recalcitrant to decay and may disproportionately influence forest biogeochemical cycles by retarding the rate at which carbon and nutrients are cycled. Ó 2013 Elsevier Ltd. All rights reserved. There is growing interest in understanding the turnover of the ectomycorrhizal (EM) fungi because of the ubiquity of this group of organisms and the large quantity of carbon (C) that is allocated to them by host trees (Hobbie, 2006). Thus, the death of EM fungal tissues represents a large litter input into forest ecosystem cycles (Langley and Hungate, 2003; Cairney, 2012; Clemmensen et al., 2013; Ekblad et al., 2013). Moreover, EM fungi envelop fine roots, forming a mantle on their exterior and modifying the biochemistry of litter inputs from fine roots (Langley et al., 2006; Koide et al., 2011), which are substantial (Jackson et al., 1997). Our knowledge of the decomposition dynamics of EM fungal litter is relatively poor, and there is likely a large amount of variation in the decomposition rates of tissues across species (Koide and Malcolm, 2009; Fernandez and Koide, 2012; Wilkinson et al., 2011). The highly melanized asexual Ascomycete EM fungus, Cen- ococcum geophilum, has a global distribution with little host spec- ificity (Trappe, 1962). C. geophilum is frequently abundant in EM communities (Dickie, 2007), thus making the turnover dynamics of this species relevant and important across forest ecosystems. Meyer (1964) noted the presence of a large fraction of C. geophilum ectomycorrhizas that appeared to be dead and hypothesized that this may be the result of an accumulation of these structures in the soil from slow decomposition rates. Corroborating this observation with vitality staining, Qian et al. (1998) found large proportions of dead C. geophilum ectomycorrhizas, relative to other morphotypes. The persistence of these structures in soil, however, has not been examined explicitly. Long persistence times of ectomycorrhizas can result from either long lifespans or from their resistance to decomposition after death. The decomposition of ectomycorrhizas can be faster (Koide et al., 2011) or slower (Langley et al., 2006) than non-mycorrhizal roots. The differential effects of EM colonization on root decomposition are likely the result of, among other factors, differences in the quality of the fungal litter (Koide and Malcolm, 2009; Fernandez and Koide, 2012). Indeed, there is reason to * Corresponding author. The Pennsylvania State University, Department of Plant Science, University Park, 103 Tyson Bldg., PA 16802, USA. E-mail addresses: cwf123@psu.edu (C.W. Fernandez), mlm572@psu.edu (M.L. McCormack), jmh656@psu.edu (J.M. Hill), PritchardS@cofc.edu (S.G. Pritchard), rogerkoide@byu.edu (R.T. Koide). Contents lists available at SciVerse ScienceDirect Soil Biology & Biochemistry journal homepage: www.elsevier.com/locate/soilbio 0038-0717/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.soilbio.2013.05.022 Soil Biology & Biochemistry 65 (2013) 141e143