The work described in this dissertation is linked by the common theme of how mercury (Hg) influences phylloplane (leaf surface) fungi. Hg is a highly toxic global pollutant of ecological and biological concern. Leaves sequester Hg and serve as a vector of Hg deposition to the forest floor. Phylloplane fungi are exposed to atmospheric Hg and are primary drivers of litter decomposition. However, it is unknown how Hg influences the fungal phylloplane community. This research contributes to current knowledge of ecological effects of Hg from the novel perspective of the fungal phylloplane community. Chapter 1 examined the effects of Hg deposition on the fungal phylloplane composition of living leaves. The fungal community was analyzed by culturing epiphytic fungi directly from leaves and using morphological and molecular techniques to identify cultures. It was determined that a single, low-dose Hg application did not significantly affect the fungal community over time. Chapter 2 investigated how fungal phylloplane cultures grew in the presence of Hg. The results indicated the effect was species specific. Some species exhibited changes in absolute growth but growth trajectories were not affected. A model was utilized to predict how the species would grow at increased Hg levels to identify which species would be sensitive or tolerant to increased Hg exposure. When the cultures were grown in pairwise interactions, Hg enhanced the competitive abilities of some species. The results indicate that Hg can affect growth of individual species, which could potentially affect community composition. Chapter 3 analyzed decomposition of Hg treated leaves in a low Hg contamination site. The leaves exposed to ambient levels of Hg decomposed more in absolute mass than the control or the four times ambient treatment. Although fungi are primary drivers of decomposition, there was not a correlation between the fungal community on decomposing leaves and decomposition. Collectively, this work demonstrates that Hg did not have an effect on the fungal community on living leaves or was a strong influence on litter decomposition at a low-contamination site. Hg can affect growth and competitive interactions of phylloplane fungi, but the effect is species specific.
Subject (authority = RUETD)
Topic
Ecology and Evolution
Subject (authority = ETD-LCSH)
Topic
Fungi
Subject (authority = ETD-LCSH)
Topic
Mercury--Environmental aspects
RelatedItem (type = host)
TitleInfo
Title
Rutgers University Electronic Theses and Dissertations
Identifier (type = RULIB)
ETD
Identifier
ETD_7068
PhysicalDescription
Form (authority = gmd)
electronic resource
InternetMediaType
application/pdf
InternetMediaType
text/xml
Extent
1 online resource (vii, 134 p. : ill.)
Note (type = degree)
Ph.D.
Note (type = bibliography)
Includes bibliographical references
Note (type = statement of responsibility)
by Katalin Malcolm
RelatedItem (type = host)
TitleInfo
Title
Graduate School - New Brunswick Electronic Theses and Dissertations
Identifier (type = local)
rucore19991600001
Location
PhysicalLocation (authority = marcorg); (displayLabel = Rutgers, The State University of New Jersey)
Rutgers University. Graduate School - New Brunswick
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Type
License
Name
Author Agreement License
Detail
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