TitleMercury effects on axeniclly grown fungal isolates and on pinus rigida and its ectomycorrhizal community
NameCrane, Sharron L. (author), Barkay, Tamar (chair), Dighton, John (co-chair), Bucking, Heike (internal member), Horton, Thomas (outside member), Rutgers University, Graduate School - New Brunswick,
SubjectEcology and Evolution,
DescriptionMercury (Hg) is a toxic global pollutant that can be highly bioavailable in terrestrial ecosystems. Although fungi are important contributors to a number of soil processes including plant nutrient uptake and decomposition, little is known about the effect of Hg on fungi. This dissertation describes efforts to investigate the effects of Hg on ectomycorrhizal and saprotrophic fungi and on Pinus rigida seedlings and their rhizosphere fungal communities. First (Chapter 1) I evaluated the effects of Hg on ectomycorrhizal fungi (ECMF) in axenic culture. Natural growth trajectories differed among fungal species, and micromolar concentrations of Hg both increased the lag phase and decreased the growth rate of ECMF. Growth rate inhibition was reduced by 20-90% when well-established ECMF colonies were exposed to 10 and 25 μM Hg, and Hg accumulation by fungal biomass was several times the concentration added to the growth media. Next (Chapter 2) I investigated the effects of soil Hg addition on the development of ectomycorrhizal communities of P. rigida seedlings using morphotype analysis. At soil additions of 88 ppm Hg and higher, seedling survivorship was less than 50%. Furthermore, addition of 88 ppm Hg to soil significantly reduced mycorrhizal colonization and altered community composition of ECMF. Last (Chapter 3), I investigated the Hg-tolerance of saprotrophic fungi from pristine soil samples. Although 67% of the culturable fungal community was culturable on media containing 50 μM Hg, the diversity of Hg-tolerant soil fungi was lower than that of the total soil fungal community. Four fungi isolated in this study were evaluated for their ability to grow in the presence of Hg. Three Umbelopsis spp. tolerated up to 20 μM, and a fourth isolate, possibly Aspergillus cervinus, was inhibited by 10-35 μM Hg. This dissertation demonstrates that Hg is toxic to P. rigida and inhibits the growth of fungi from two important functional groups (ECMF and saprotrophs). Furthermore, it provides evidence that Hg alters ECMF and saprotrophic fungal communities. Finally, it emphasizes a need for further research into the effects of Hg on fungi and their ecosystem services.
NoteIncludes bibliographical references
Noteby Sharron L. Crane
CollectionGraduate School - New Brunswick Electronic Theses and Dissertations
Organization NameRutgers, The State University of New Jersey
RightsThe author owns the copyright to this work.