Natural Science Seminar - Abstracts Spring 2008

Christopher Fusting
Jan. 28, 2008
Predicting Oriental Bittersweet (Celastrus orbiculatus) Habitat using GIS and CART Modeling
Mentor: Dr. Mark Brenner

Abstract: Geographic Information System (GIS) technology has become an important tool in ecology.  One application of GIS is habitat mapping and prediction.  A target species’ habitat can be sampled and then predicted given the availability of predictor variables (data layers) over the area of study.  Oriental Bittersweet (Celastrus orbiculatus) is a non-native, invasive woody vine common in the southeastern Appalachians.  Originally introduced from Asia for ornamental purposes, C. orbiculatus has spread rapidly due to poor management, prolific seed production, shade tolerance, and a lack of natural enemies.  The objective of this study is to develop a habitat prediction model of Celastrus orbiculatus using GIS and classification tree modeling.  Presence and absence data for C. orbiculatus was gathered in the Bent Creek Experimental Forest, NC, at 88 random plots.  The resulting habitat and non-habitat data was combined with slope, aspect, elevation, distance to stream, and distance to roads and trails GIS data of corresponding location.  Classification and Regression Tree modeling (CART) software was used to build a classification tree of C. orbiculatus habitat and non-habitat.  The resulting classification tree was manually examined and several equations were derived from it for use in habitat and non-habitat prediction map generation.  Two maps were generated in Arcmap 9.2 and tested for accuracy using a 42 plot grid of presence and absence habitat data of C. orbiculatus sampled prior to the beginning of this study.  The habitat map was 5% better than random (25%) at predicting the presence of C. orbiculatus.  The non-habitat map was 13% better than random (75%) at predicting absence.  The results indicate some success in correctly predicting the habitat and non-habitat of C. orbiculatus.  Through the employment of this habitat prediction model, land managers could target C. orbiculatus for removal and develop land use policies that minimize its spread.

Moriah Floyd
February 4, 2008
Soil-management history as a factor in Mexican bean beetle (Epilachna varivestis) preference for string bean plants (Phaseolus vulgaris).
Mentor: Ms. Karen Joslin

Abstract: Research has shown that the nutrient management history (NMH) of a soil can influence insect interactions with plants grown in those soils.  There are two possible causes of this interaction: the fertilizer applied annually, and the accumulated effects of the soil’s NMH.  Research has found that insect pest preference can be mediated by a soil’s NMH.  My objective was to determine if the soil management history of the soils used in this study affected feeding preference and oviposition of Mexican Bean Beetles (Epilachna varivestis) on string beans (Phaseolus vulgaris). Soils were collected using random representative sampling in the spring of 2007 from two farms in Leicester, Buncombe County, North Carolina. Soil A had been under conventional management for 25 years, while soil B was under certified organic management for 20 years. Soils were analyzed for nutrients and 1.65kg of each was placed in 12 plastic pots (n=24).  Soil tests indicated that fertilizer was unnecessary for either soil, but that 7.11grams of agricultural lime per pot was required for soil B. Plants were placed in a growth chamber with a day length of 15 hours, a daytime temperature of 26 C, and a nighttime temperature of 20 C.  Plants were randomly arranged and received DI water initially to saturation, followed by watering with DI for four seconds, every other day.  Planting of string beans seeds (4/pot) was followed by weeding and thinning (1/pot), ten days post emergence. Mexican Bean Beetles were randomly applied at a rate of 20 beetles per 24 plants when plants were 70% mature.  Ovipositional data were collected only once, due to rapid onset of plant disease.  Herbivory was measured at 70% of plant maturity. Results from the single oviposition data collection were not enough to perform a statistical analysis.  A Two-Sample T-Test was used to analyze the herbivory data.  There was no significant difference (P=0.069) between the two soil types; soil A had a mean of 2.83 percent defoliation and the mean of soil B was 4.83 percent defoliation.  The lack of difference between the soils may have been because their NMH’s were not very dissimilar, additionally; the CEC of soils in the Southeast is very low, possibly reducing the range of difference so that a statistical difference would not be found.

Virginia Wolking
February 4, 2008
Plant Species Cover Composition in Northwest Minnesota Conservation Reserve Program Fields
Mentor: Dr. Lou Weber

The Conservation Reserve Program was initiated in 1985 to reduce soil erosion, protect water quality and provide wildlife habitat on erosion prone agricultural land.  Landowners receive payments for enrolled CRP based on the agricultural rental value of the land.  In order to qualify for full monetary compensation for enrolled CRP the landowner must follow guidelines set by local Farm Service Agency offices.  While these guidelines specify outcomes of management, the landowner determines the practices used to sustain the CRP.  My objective is to better understand how management regimes affect plant species in northwest Minnesota grassland CRP.  CRP Management regimes examined in this studying included mowing, aerial application of herbicide, and cattle grazing.  Seeding plans for three CRP fields surrounding Euclid, Minnesota were obtained from the local Farm Service Agency office.  Plant species cover was estimated using the Daubenmire method in the three fields.  Each field was sampled over a two day period from July 29th through August 12th, 2007.  The Shannon-Weiner function, a measure of both plant diversity and equitability was used to analyze plant species cover estimates.  The mowed field received a function score of 2.055, the sprayed field scored 1.71, and the grazed field scored 3.05.  The Shannon-Weiner function score increases as plant diversity and equitability increase, indicating that the grazed field had the highest diversity and equitability, measures of ecosystem health. The results suggest that disturbance in the form of cattle grazing increases plant diversity and equitability in northwest, Minnesota CRP.  Suggestions were made to provide farmers with management handbooks, informed county extension agents and revised guidelines on CRP management practices.

Thomas B. Otey
February 18, 2008
Effects of Off-Highway Vehicle (OHV) Traffic on Stream Microinvertebrate Populations in the Tellico River Watershed
Mentor: Dr. Paul Bartels

Abstract: The Upper Tellico Off-highway Vehicle (OHV) Area is a designated motorized vehicle recreation area in Nantahala National Forest. The 38 miles of off-road trails are interlaced by the headwaters of the Tellico River. Erosion of trails and consequent sedimentation in Tellico tributaries has caused a rise in concern regarding the environmental impacts of the OHV Area. Stream microinvertebrate populations could be used as a means to assess the impacts of sedimentation on aquatic ecosystems. This study examines the effects of the Upper Tellico OHV Area on stream microinvertebrate populations. Sediment samples were taken from two Tellico tributaries inside of the OHV area as well as from two reference tributaries that join the Tellico outside of the OHV Area. Microinvertebrates were identified and counted for each stream. The median total densities of microinvertebrates were significantly higher in two reference streams outside of the OHV area than in one stream inside the OHV area (Kruskal-Wallis ANOVA, P=0.001). Median Simpson’s Diversity Index values calculated at the phylum level for the four streams were not considered significantly different (Kruskal-Wallis ANOVA, P=0.159). Rank/Abundance graphs suggest that phylum evenness was similar between the two reference streams, while more variable between the two streams inside the OHV area. Within the phylum Arthropoda, the relative abundance of midges was higher than that of copepods within the OHV area. This trend was reversed in the reference streams outside of the OHV area. Due to lack of replicates and uncontrolled environmental factors, the differences between the streams cannot be attributed to the OHV area. However, within these specific streams, a correlation was observed between high levels of sedimentation and decreases in total microinvertebrate densities.

Anita Goodrich
The Growth and Survival of American Butternut (Juglans cinerea) Across a Natural Shade Gradient
February 18th 2006
Mentor: Dr. David Ellum

Abstract: Seedlings respond to the quality and quantity of Photosynthetically Active Radiation (PAR) through shoot elongation and expansion. Butternuts are valued as mast producing species due to the high nutritive levels of the nuts.  They are susceptible to an introduced fungus that causes mortality in seedlings that show no natural genetic resistance. The objective of this study was to determine if there is a relationship between light intensity and growth of American Butternut (Juglans cinerea). Genetically resistant seedlings were transplanted into a preexisting canopy gap at the Warren Wilson College Forest.  A variable shade gradient between ten and ninety percent PAR was determined for the site.  Data were collected on total height, root collar diameter and number of stem and root before planting and at the end of a single growing season.  The final conditions of the seedlings were also measured at the end of the growing season.  Linear regression analysis was used to identify relationships between light intensity and height growth, root collar diameter, final condition of stem and number of stem and root sprouts.  Regression analysis identified a correlation (r2 = 0.62) between light and the numbers of stem sprouts produced by individuals with positive height growth.  No relationship was established between light and any of the other growth variables. The survival rate for the site was 89% but no relationship between survival and light was identified. The lack of relationship between light and growth is likely related to initial transplant shock.  These seedlings will continue to be monitored as part of a collaboration with the University of Tennessee Tree Improvement program aimed at identifying appropriate sites for the restoration of blight resistant American Butternut.

Liz Martin
February 25, 2008
Comparing propagation methods for conserving an endangered woodland herb: Lysimachia fraseri, Fraser’s loosestrife
Mentor: Dr. Dave Ellum

Abstract: Fraser’s loosestrife (Lysimachia fraseri) is an endangered herbaceous perennial native to the Southern Appalachian mountains.  There are an estimated 40 to 75 populations left throughout its range.  Sexual reproduction is the major limiting factor in the species’ success, although it asexually reproduces by rhizome and has been successfully propagated by rhizome.  The objective of this study was to determine the most successful propagation method for conserving Fraser’s loosestrife by comparing stratification methods for the soil seed bank as well as monitoring two transplanted populations of the species.  Two populations were removed from gravel road sites and transplanted to an available field on the Warren Wilson College campus.  The first population was transplanted in May of 2007, the second in September of 2007.  Soil samples and gravel samples were collected from the site of the second transplanted population.  Two treatment methods were used to stratify the samples; treatment A went through one freeze/thaw cycle, and treatment B went through 4 freeze/thaw cycles.  Samples were then germinated in a greenhouse for 7 weeks.  There was no germination of Fraser’s loosestrife for either soil type or stratification method, though there were many germinants of other species for both stratification methods.  Secondary shoots were observed in October of 2007 from the first transplanted population, and the plants were green and healthy.  Most of the transplants of the second population were not alive above ground when observed in October, but underground rhizomes may be viable.   Results show that propagation by rhizome is a viable conservation method, while propagating from the soil seed bank surrounding a population may not be. 

Kenmei Kato
February 25, 2008
Dragonflies (Anisoptera) and Damselflies (Zygoptera) at Warren Wilson College
Mentor: Dr. Lou Weber

Abstract:   Dragonfly and damselfly conservation has been a growing concern world-wide.    According to the International Union for Conservation of Nature and Natural Resources (IUCN) 33% of odonates (dragonflies and damselflies) world-wide are of conservation concern. Habitat degradation and habitat loss due to development have greatly reduced suitable odonate habitat.   The southern Appalachians serve as habitat for a particularly diverse amount of odonates mainly because of the rich habitat and steady climate.  Development is the main threat for odonates in the southern Appalachians.  The objective of my study was to conduct a survey of the dragonfly and damselfly species on the Warren Wilson College campus and compare it to the Great Smoky Mountains National Parks species inventory (ATBI).  The purpose was to compare the species diversity of an ecologically protected area to the Warren Wilson College campus so that conservation measures could be assessed and a baseline established.  Observations were conducted throughout the months of August - December 2007 using binoculars, field guides, digital camera, and butterfly net.  With limited time and resources a genus from every family documented by ATBI except for the Petaltail family was observed; 23 species in total.  These data suggest that there is abundant diversity on the Warren Wilson College Campus and more research should be conducted with the possibility of finding critically imperiled species. 

Julia Mead
March 3, 2008
Characterization of Volatile Compounds in Clover Honey (Trifolium spp.) by Solid-Phase Microextraction and Gas Chromatography Mass Spectrometry
Mentor: Dr. John Brock

Abstract: Honey, the natural sweetener produced by honey bees (Apis mellifera), is a unique mixture originating from several sources.  Volatile organic compounds (VOCs) originating from the floral source, make up a small percentage of honey composition, but may be used as indicators of the botanical or geographical origin of honey.  The objectives of this study were threefold: to establish a method to characterize the VOCs in clover honey, to compare the chemical profile of clover honey to the sensory profile, and to determine if there is a statistical significance between the concentrations of volatile compounds in honey from two geographical regions.  The method was executed using solid phase microextraction (SPME), a solvent-free extraction technique, coupled with gas chromatography mass spectrometry to separate different volatiles.  At this time, mean concentrations of two flavor compounds, benzaldehyde and phenylacetaldehyde, have been measured in parts per million for three clover honey samples from Northern California.  Also, a taste test was performed rating flavor, aroma, sweetness, and color.  An ANOVA test determined that no significant difference exists between flavor (p=0.897), aroma (p=0.347), or sweetness (0.055) ratings for the three honeys, although the color ratings were found to be statistically significant (p≤0.0001).  Though mean concentrations of two volatiles were found for three honey brands, it appears as though there is no correlation between concentration of flavor compounds and sensory perception of flavor or aroma.  Future research will include a characterization of three honey brands from the Western North Carolina region, with mean volatile concentrations compared to those from Northern California.       

Jill Loury
March 10, 2008
The Effect of Trout Farm Effluent on Periphyton Growth
Mentor: Dr. Mark Brenner

Abstract: For over 150 years trout and other fish have been farmed in North America.  There is little known of the effects that trout farms have on the natural environment, especially the communities within the water bodies they feed into.  Periphyton is a community of algae, fungi, bacteria, and microzoans that thrive in streams.  This mixture of autotrophs and heterotrophs require different nutrients to maintain themselves.  The loading into a stream with fecal matter and dissolved food particles from the trout farm may disrupt the natural balance between autotrophs and heterotrophs within the periphyton communities.  A total of twenty rock samples were taken from five sites upstream and downstream of a trout farm output at Shope Creek, NC.  The samples were analyzed for Chlorophyll a, which is a measure of autotrophs,  and Ash-Free Dry Mass, a measure of total periphyton biomass, so that an Autotrophic Index could be made.  A nonparametric t-test, the Mann-Whitney test, was run for the Ash-free Dry Mass, Autotrophic Index, and Chlorophyll a Analysis because they did not pass normality tests.  The AFDM P-value was 0.5476.  The Autotrophic Index P-value was 0.6905.  Neither of these was statistically significant.  The Chlorophyll a Analysis had a P-value of 0.0952, making it not quite significant.  There was very high variance within my samples, and it is suggested to try and control for sampled substrate and depth.  This experiment was performed in the winter and will hopefully be a baseline study for others looking at periphyton growth during different seasons.

Holly Spier
March 10, 2008
Social Comparison and Affect Stimulation as a Motivation to Gossip

Mentor: Dr. Vicki Garlock

Abstract: Research suggests that gossip, a common form of communication, can be used for social comparison, social bonding, or status-enhancement.  Social comparison includes upward social comparison (gossiping for selfish gains) and downward social comparison (gossiping for one’s pursuit of a positive self-view).  This study attempts to establish the relationships between the tendency to gossip, the tendency to engage in social comparison (both upward and downward), and the tendency to respond intensely to affect-provoking stimuli. College aged participants filled out three separate questionnaires assessing these three constructs.  A fourth measure was aimed at assessing interest in gossip about celebrities versus peers. Results showed several significant, positive correlations.  These included correlations between the tendency to gossip and social comparison, the tendency to gossip and affect intensity, and the tendency to gossip and interest in gossip.  Multiple regression analyses suggest that the variance in tendency to gossip is explained by both the variance in social comparison scores and variance in affect intensity scores. The findings also suggest that the motivation behind gossip is complex with several factors playing a role.

Delaney Burke
24 March 2008
Kleptoparasitic attack methods by Laughing Gulls (Larus atricilla) at a seabird colony on Eastern Egg Rock, Maine

Mentor: Dr. Lou Weber

Project Puffin maintains seven research islands in the Gulf of Maine that are home to mixed colonies of rare seabirds.  On Eastern Egg Rock, ME, there is extensive control of predatory gulls, but minimal control of Laughing Gulls (Larus atricilla).  The Laughing Gull population on the island has been increasing 10% a year since 2002 and includes 1705 nesting pairs.  The problem is that Laughing Gulls are known to engage in kleptoparasitism, the process of one organism stealing food from another of the same or different species.  This can have negative affects on other seabird species and may be affecting endangered terns (Sterna spp.), the featured Atlantic Puffins (Fratercula arctica), or other species. Because little research has been done on the effect of kleptoparasitic Laughing Gulls on the island’s other seabird species, my objective was to determine the target hosts, the success rate, and the method of attack. This information will be used to asses the current Laughing Gull policy on the island in consideration of more aggressive control. Observations were made in one to three hour blind stints from 22 June to 18 July 2007. The time, host, method of attack, and outcome of attack were recorded. The method of attack was determined by the height of attack:  boulder berm attacks were less than 1 m above the rocks, aerial boulder berm attacks occurred 1 – 3 m above the boulder berm, aerial attacks were more than 3 m above the rocky boulder berm. Results showed that Black Guillemots (Cepphus grylle) were the host preference with 636 of 678 observed attacks, and were attacked mainly at the boulder berm level. The overall success rate of Laughing Gulls was 19.2%. Boulder berm and aerial boulder berm were the most common methods. Terns, other Laughing Gulls, and Atlantic Puffins were primarily attacked aerially. The success rate increased as the number of gulls in the group increased, but the individual success of a gull in a group remained constant as the group size increased. While Black Guillemots are currently not rare, more research is needed to measure the effects of kleptoparasitic Laughing Gulls on chick fledgling success on Black Guillemots. Terns were victimized rarely, but an increase in Laughing Gull numbers may provide more stress and disturbance. A more intensive Laughing Gull control is needed on Eastern Egg Rock to ensure the survival of the rare seabird species.

Conor McGeehan           
March 30, 2008
Effect of distance from logging roads on consumption rate and preference of Celastrus orbiculatus and Ilex opaca seed by small mammals in the southern Appalachians

Mentor: Dr. David Ellum

Abstract: Non-native invasive plant species pose both ecological and economic threats to native plant communities of the southern Appalachian forests of the United States. Oriental bittersweet (Celastrus orbiculatus) is a non-native twining vine introduced from Asia that is known to cause significant damage to forest systems.  Small mammals are known to be seed predators on a variety of forest plant species. While avian species have been determined as a source of predation and dispersal for Oriental bittersweet, little is known about the role small mammals play in the predation and dispersal of the species. While small mammals may offer a pathway of distribution on a small scale, roads as biological corridors can provide a pathway for dispersal on a much larger scale. Two objectives were defined for this study; 1) compare the consumption of oriental bittersweet fruits and a native species, American holly (Ilex opaca), in relation to distance from road edge and 2) compare small mammal abundances to forest stand structure. The study was conducted at the Bent Creek Experimental Forest in Asheville, NC. The first objective was tested using feeding stations that were monitored during November and February. The second objective made use of trapping data that was collected over 6 consecutive days in July. The Lincoln Peterson technique was used to estimate abundance small mammals. Linear regression analysis was used to determine relationships between small mammal abundance and basal area, stand density and coarse woody debris. Results showed a higher abundance of mice at distances 25m and 50m from road, compared to the road edge.  The abundance of mice was related to both stand basal area (r2 = 0.76) and stand density (r2 = 0.66), but not coarse woody debris. No feeding preference between Oriental bittersweet and American holly could be determined due to a lack of berry consumption. For the sites sampled in this study and during that sampling period, white footed mice preferred not to consume Oriental bittersweet and American holly berries.

Seanna Bellinger
March 31, 2008
The Effect of Vocal and Instrumental Music on Students’ Cognitive Performance

Mentor: Dr. Vicki Garlock
Abstract: Researchers disagree about whether music enhances or impairs cognitive performance. This is partly because the relationship between music and cognitive performance can be moderated by additional factors, including personality and study habits.  My primary objective was to assess the impact of vocal music vs. instrumental music. A secondary objective was to determine whether musical genre and study habits influenced how music affected performance.  Participants were placed in one of five conditions (instrumental rock, vocal rock, instrumental hip hop, vocal hip hop, and control). Participants were given three cognitive tasks assessing memory, spatial ability, and math ability.  Participants then completed a short questionnaire. ANOVAs on all three dependent measures showed no statistically significant differences across the five conditions; however, the ANOVA on the arithmetic test approached significance (P = 0.091). Post-hoc analyses indicated a statistically significant difference between the Hip Hop Instrumental group and the Control (P = 0.006).  Statistical tests also assessed the effects of type of music (instrumental, vocal, control) and musical genre (rock, hip hop, control) more generally.  Math scores were lower in the Instrumental group when compared to Control (P = 0.025) and lower in the Hip Hop group vs. Control (P = 0.016).  Analyses on study habits showed no significant effects.  My results suggest that instrumental music and hip hop music may have more of a debilitating effect on students’ cognitive performance, particularly math, than vocal music or rock music.  Small sample sizes may attribute to some results corresponding with previous research better than others.  

Eliza Sydney
April 7, 2008
Ionic profile of the groundwater and surface water at Warren Wilson College

Mentors: Mr. Robert Hastings and Dr. Victoria Collins

Abstract: The Swannanoa River is a surface water body that runs through Warren Wilson campus and is part of the greater French Broad River Basin.  The French Broad River basin is a unique area of hydrologic study because over 70 percent of surface water discharge is from groundwater sources.  The contribution of groundwater to surface water is commonly overlooked but is an important component of watershed hydrology. Relatively few studies in the Southern Appalachian region have focused on groundwater contribution to streams.  Chemical analysis of natural water requires knowledge of rock composition.   To investigate the groundwater contribution to surface water, ions released into solution after contact with underlying geologic material should be measured.  This study had three objectives.  The first was to find the concentrations of ions in the groundwater and surface water, the second was to investigate variability in ionic composition of groundwater and surface water.  The last objective was to determine the relationship between base flow and total stream flow.   Ionic ratios in milliequivalents were measured and converted to stiff diagrams to determine changes in time and space.  Though rock types in the area yield very low total ion compositions, there are notable changes in ionic composition among the groundwater and surface water as well as notable differences in the surface water during periods of high and low flow.  Results suggest that groundwater and surface water are in communication and should be viewed as one resource.  As increasing development and droughts continue in our area, knowledge of whole hydrologic systems will be increasingly pertinent.

Eli Dwight
April 7, 2008
Comparison of Forest Vegetation by Aspect on Suicide Ridge

Mentor: Dr. David Ellum

Abstract: Phytosociology is the study of the composition, distributions, and interactions of plant communities. Slope aspect is an important site variable that can strongly influence forest structure and composition. The objectives of this study were to: 1.) systematically compare the forest structure and phytosociology of the North and South aspects, and 2.) to inform the long term management of the  Warren Wilson College forest.
This study was conducted on the Warren Wilson College Forest (251 ha) in Swannanoa, NC. The forest is of the low elevation oak-hickory type, common to the mixed mesophytic forests of the Southern Appalachians.  Data was collected on Suicide Ridge, a 51 ha stand with well-defined northwest and southeast aspects and similar percent slope and concavity. An area of 3.6 ha on each slope was sampled at an intensity of 7.5% using 27 100m2 plots per site. All trees>10cm were identified and diameter at breast height was recorded, while all small diameter stems were identified and counted. Abundance of exotic invasive species was estimated using 1m2 plots. Comparisons of forest structure and composition were made based on basal area and density, diameter distributions, species diversity and importance values and abundance and type of invasive species
When all species were grouped, ba/ha, stems/ha, and stems<10cm/ha did not differ significantly between the north and south aspects. The two aspects showed low beta diversity (Sorenson’s Coefficient of Communities 0.85) and comparable alpha diversity (Simpson’s Index of 0.59 (north) and 0.47 (south)). Analysis conducted at the species level demonstrated greater differences between the north and south aspects. Importance values results corresponded with life histories of species present in a mixed mesophytic forest. There was a high density of small diameter stems of Pinus strobus on the north side while L. tulipifera was the most dense species on the south side. Dominance of Quercus spp. in the overstory and the absence of individuals from the genus in the understory may indicate a future shift in forest composition for both aspects. Exotic invasive species were absent from the north side, while four species were found in abundance on the south side. At least one exotic invasive species was present in 72.2% of subplots on the south side.  It is apparent that aspect influences the structure and composition of exotic invasives species and of trees at the species level on Suicide Ridge.

Beth MacLeod
April 7, 2008
Method Development of Salicylic Acid Extraction from Cherokee Purple (Lycopersicon lycopersicum) Leaves

Mentors: Dr. Michael Torres and Dr. Joe Young
Abstract: Salicylic acid is a colorless, crystalline organic acid. It is stored in plants as a phytohormone, a plant hormone that helps regulate a plant’s growth. Salicylic acid has an important role in plants as an endogenous signal for the induction of systemic acquired resistance. Systemic acquired resistance is defined by Ross, “ an induced system of resistance triggered by pathogens that cause rapid cellular necrosis of infected tissues.” Salicylic acid also has an important role in plant communication. Though there are already methods developed for the extraction of salicylic acid, Warren Wilson College does not have the required resources for these methods. Thus, the objective of my study was to develop a method to extract salicylic acid from Cherokee Purple using the available resources at Warren Wilson College. I extracted salicylic acid from tomato leaves using a sochlet extraction. I evaporated the ethanol and dried my samples using rotary evaporation. I resuspended my samples in a sodium acetate buffer with β -glucosidase, an enzyme which catalyzes the cleavage of individual glucose molecules. I used high performance liquid chromatography with fluorescence for the detection of salicylic acid. My results had a retention time of 2.478 for my 10ppm standard. My first sample had a retention time of 2.127, my second sample had a retention time of 2.132 and my third sample had a retention time of 2.127. I also spiked my 1st sample on two different runs. The unspiked sample had 69.38% salicylic acid. My first run had 77.46% salicylic acid, which is an increase by 8.07%. My second run had 78.11% salicylic acid, which is an increase by 8.72%. The data of retention times and spiking suggest that I may have found salicylic acid. I still plan to change the wavelengths and to not add β-glucosidase to my other examples to see if the data still points to salicylic acid. Salicylic acid is an important molecule for the induction of systemic acquired resistance and for plant communication. The best part about learning if salicylic acid can have future uses as a application on plants to improve the overall health, is knowing that when using salicylic acid, one is using a naturally produced molecule by the plant.

Laura Righter
April 14, 2008
Antioxidant Capacity for Various Varieties of Tomatoes (Lycopersicon esculentum)

Mentor: Dr. Victoria Collins

Abstract: Research shows that tomatoes are an important source for antioxidants. There are two lipid soluble carotenoid antioxidants found in tomatoes, lycopene and beta-carotene. Lycopene is responsible for the red pigments seen in tomatoes, so red and black tomatoes have high levels of Lycopene. Beta carotene is responsible for the yellow pigments seen in tomatoes, thus, yellow and tangerine tomatoes have high levels of beta-carotene. Much research has been done on the antioxidant capacity of red tomatoes, but little has been done on tomatoes with yellow, tangerine, or black colors. Therefore, my objective is to compare the antioxidant capacity of several tomato varieties of different color. In addition, very little research has been done to compare the antioxidant capacity of hybrid to heirloom tomato varieties. Therefore, my second objective is to compare antioxidant capacity of heirloom and hybrid varieties. This study compared four fruits from each of eight tomato varieties.  Lycopene and beta-carotene were extracted with hexane and vacuum concentrated to 20 ml.   For every sample 100 microliter of extract was added to 2 ml of DPPH free-radical. A spectrophotometer was used to determine the antioxidants’ capacity to scavenge free-radicals over duration of 30 min.  Statistical analysis compared two varieties of each of the four colors using a one-way ANOVA which found the results to be highly significant (p< 0.001). The individual means were compared using Tukey’s test.  Pooled means of antioxidant capacity of all 12 hybrids and all 20 heirlooms were compared using an unpaired t test.  The antioxidant capacity for hybrid varieties did not differ from that of heirloom varieties (p= 0.867). It appears that tomatoes with pigments representing high levels of lycopene have the highest antioxidant capacity.   The variation in antioxidant capacity among the different colors was greater that the variation between the hybrid varieties and heirloom varieties.

Forrest Heacock
April 14, 2008
Heavy metals in the Swannanoa River: Potential Pollution from a Remediated Junkyard

Mentor: Dr. John Brock

Abstract: Heavy metals, such as chromium and lead are important environmental pollutants, particularly in areas where anthropogenic pressures are high. Their presence in the environment can have negative effects on all members of an ecosystem, and their ability to be bioaccumulated by vegetation and microbes allows for the possibility that they may be entering a human population through its diet. Cars today contain a number of different potentially toxic metals including zinc, chromium and copper in their electrical components as well as a good amount of lead found in the battery. Due to acidic rainwater runoff it is possible that the aforementioned metals may be leeching from immobilized cars into nearby soils. In areas where there are a great deal of immobilized cars, namely junkyards, it is possible that the degree to which heavy metals are entering the environment is significant. This problem becomes even greater when the heavy metal pollution enters a waterway as the mobility of the metals increases dramatically. This study attempts to determine if an area which used to be a junkyard had been contributing heavy metals to the nearby Swannanoa River by doing ICP analysis of sediment samples.

Jodi M. Ferrell
April 14, 2008
How Binge Drinking Affects Risky Behaviors at Warren Wilson College

Mentor: Dr. John Brock

Abstract: Approximately four out of five college students drink alcohol, and 40% of college students are classified as heavy episodic drinkers.  Condom use among college students is less than 40%, and it has been found that heavy episodic drinkers are three times more likely to have multiple sex partners.  Various surveys have been conducted at Warren Wilson Campus in order to observe frequency of alcohol consumption, risky behaviors, and sexually transmitted diseases (STDs).  In 2007, a zoomerang study distributed by the Office the Student Life showed that although 17% of participants admitted to regretful behavior only 6% reported that they considered their drinking to be problematic.  STD surveys conducted as a class project by the epidemiology course offered at Warren Wilson College have revealed improvements in condom use and STD prevalence on campus from 2004 to 2006.  Epidemiology is the study of human populations, which attempts to link human health effects to a particular disease or condition.  Through the use of an epidemiological survey, the objective of the study was to analyze the prevalence of risky behaviors as a result of binge drinking in Warren Wilson College students.  The survey was open for voluntary participation in Canon Lounge during lunchtime at the end of the fall semester of 2007.  The participants signed a consent form before completing the survey, and their identity was anonymous.  The sample population was 20% of the total population with the demographics of the sample having more freshman and less sophomores, juniors, and seniors than the total population.  The main source of obtaining alcohol for underage drinkers was reported to be from people of legal drinking age.  As a result of binge drinking, more class sessions were missed than shifts of work.  The majority of participants consider themselves social drinkers, but 9% of seniors consider their drinking be problematic.  Condom use while binge drinking was found to be 40%.  A portion of each class reported having four to six sexual partners while binge drinking during the fall semester of 2007, but the sophomore class had the highest value at16%.  STD cases contracted while binge drinking during the past semester was reported to be 2%.  The data collected may indicate elevated risky behaviors while binge drinking, such as driving, engaging in unprotected sex, and having multiple sexual partners.

Chelsea Peterson
April 21, 2008
Morphometric Analysis of Retinoic Acid Treated Zebrafish

Mentor: Dr. Jeff Holmes

Abstract: Zebrafish are a common developmental model used to study chordates.  They are coveted in the field of developmental biology because of their fast development and transparent embryos.  To study the effect of retinoic acid in the development of zebrafish eyes, eggs were immersed in a retinoic acid solution with a concentration of 0.05 micrograms/mL and allowed to develop for 72 hours.  A control group also developed for 72 hours, but were immersed in tank water only.  All embryos were fixed in a 0.35% gluteraldehyde solution, then oriented under a dissection microscope where the eye area was measured in proportion to the swim bladder area using a C14 camera and i-Solutions software.  The eyeball and swim bladder areas of untreated embryos were compared to eyeball and swim bladder areas of retinoic acid treated embryos using unpaired t-tests.  Retinoic acid treated embryos had larger eyes and swim bladders with p values of <0.0001.  The eye/swim bladder ratios of retinoic acid treated embryos were significantly larger than the ratios found in untreated embryos with a p value of >0.0001.  The techniques and equipment used  in this study demonstrated the ability to quantify microscopic parts in embryos, and can be repeated in future studies.

Sarah Gaskin
April 21, 2008
Pool Leakage and Mass Wasting Relationship on the Warren Wilson College Campus

Mentors: Robert Hastings and Dr. Mark Brenner

Abstract:  Mass wasting is defined as the downward movement of land due to gravity. There are four main contributing factors to mass wasting: slope, water, vegetation, and underlying rock. Mass wasting is triggered by over-steepening slope, adding water to the system, removing vegetation, and decreasing the internal cohesion of underlying material. Some signs may be cracks in pavement, leaning or bowed trees, fence posts, or telephone poles, sunken road beds, cracked building foundations, surface springs or seeps, and out of plumb door frames. Mass wasting is occurring on campus behind the pool at the back of the parking lot. The Warren Wilson College pool was leaking 1800 gallons of water a day for about a year. The objective of my study is to determine if the pool leak is triggering land movement, or if the two are unrelated. For my methods, I determined past land use, drilled four bore holes, installed one monitoring well, took water samples, and surveyed the area for relative elevations. Historic aerial photos and topography maps showed a small stream drainage through the landslide area, that has been flattened and filled since the 1940’s. Bore holes revealed about seven to nine feet of fill dirt, and showed dry soil. Water samples near the pool contained no detectable chlorine. The lack of wet soil near the pool and lack of chlorine in my monitoring well indicates that the pool is most likely not triggering this landslide. An over-steepened slope and water underflow is what is contributing to the potential landslide.

Ian Martin
April 28, 2008
Structural cues hypothesis and the home range of the Pileated Woodpecker (Dryocopus pileatus)

Mentor: Dr. Lou Weber

Abstract: The Pileated Woodpecker is the largest woodpecker in North America and is a common resident of deciduous/coniferous forests in the Eastern and Western United States. The home range of the Pileated Woodpecker is defined as the area in which it occupies and actively defends. Dead wood is the major foraging substrate including snags, down wood and dead parts of live trees which contain wood boring invertebrates. There are three different hypotheses that attempt to explain the observed inverse relationship between home range size and food abundance: Direct Monitoring Hypothesis, Intraspecific Competition Hypothesis, and the Structural Cues Hypothesis.  The objective of my study is to test the structural cues hypothesis by examining the relationship between home range size and a specific structural characteristic of Pileated Woodpecker habitat. First home range was defined and then within the home range six 30x30m sample plots were chosen to measure the volume of wood. Minimum sample sizes for logs were chosen based on observation and previous research. The number of logs per hectare was much greater and the home range was much smaller in comparison to two other studies. The data showed volume of logs to be consistent with the two other studies. The similarity of the log volume data in comparison to the other two studies lends support for the structural cues hypothesis. The consistency of this data may indicate the actual needed amount of log volume per hectare of the Pileated Woodpecker.

Lester Gulledge
April 28, 2008
Changes in Asheville’s Land cover, and Resulting Effects on Air Quality

Mentor: Dr. Dean Kahl

Abstract: An urban forest is characterized by the integration of trees within dense development. Rapid urbanization of the United States, as  well as decreasing tree management budgets, makes protection of urban forests increasingly important. Trees and shrubs in an urban setting have inherent aesthetic values, as well as quantitative values, such as air quality mitigation. The trees of an urban forest store and sequester gaseous pollutants such as NOx, SOx, CO, O3, and pm10. Removal rates of these pollutants vary based on tree cover, pollution concentration, and length of leaf-in season. Canopy cover and pollutant removal rates vary based on land use, and the historic ecotype of the area in which the forest is located. The objective of this study was to determine if there was a difference in canopy cover, and removal rates of gaseous and particulate pollutants between 2002 and 2006 by the urban forest in downtown Asheville.  The objective was also to learn about the structure and distribution of this urban forest by comparing canopy cover, and the ratios of canopy to road and canopy to building in one year, in differing land use types. ArcGis and CITYgreen software was used to perform this analysis. Canopy coverage rates in 2002 and 2006 were compared using a Wilcoxon matched pairs signed ranks test, and 2002 coverage rates did not differ from those of 2006 (p=.9453). Canopy coverage in residential zoning districts did not differ significantly from that of commercial districts. Zoning districts that are exempt from Asheville’s landscape and buffering standards had significantly less canopy coverage than districts that are not exempt. Changes within a four year period were not significant, however no increase in tree cover was observed within study plots as the result of raster calculations. This contradicts the Unified Development Ordinance. All districts exhibited a high amount of statistical variance, however 95% confidence intervals of mean tree coverage met American Forests recommendations. 

Julian Kern
April 28, 2008
Inhibitory Effects of Allelopathic Compounds on the Seed Germination of Invasive Non-native Plant Species.

Mentor: Dr. David Ellum

Abstract: Allelopathy is a plants ability to create compounds, usually metabolic by-products or secondary metabolites, which directly influence another plant species. Previous research shows that certain plants produce allelopathic compounds that have inhibiting effects on other plant species.  The objectives of this study are A) to determine if the allelopathic compounds of tree species inhibit the seed germination of invasive non-native plant species and B) to determine whether a compound from an invasive non-native tree species is more inhibiting than a compound from native tree species.  Two native tree species, Robinia pseudoacacia, and Juglans nigra, and one non-native, Ailanthus altissima were used to test allelopathic effects on the germination of two non-native species, Lonicera japonica and Elaeagnus angustifolia. Aqueous solutions with concentrations of 4 g/L and 10g/L were made from ground root bark of each of the three species. Seeds were sealed in Petri dishes after being watered with the solutions and germination was monitored daily for 21 days. The entire experiment was replicated one week later. Chi-squared tests were used to test for differences in germination success between the allelopathic solutions and a D.I. water control.  L. japonica had no germination success in any treatments groups, most likely as a result from factors other than allelopathy.  Grouped data showed that the presence of all three allelopathic compounds had significant negative effects on the germination of E. angustifolia.   When tested separately against the control, the presence of R. pseudoacacia (p=0.0085) and J. nigra (p=0.0085) were only significant at high concentrations.  A. altissima was significant at both the low (p=0.0085), and high (p=0.0085) concentrations.  Results indicate that the non-native A. altissima has a greater effect on the germination of E. angustifolia than the native species R. pseudoacacia and J. nigra.  Results also suggest that the compounds in A. altissima have the potential to be used as herbicides on other invasive non-native species, while at the same time controlling the invasive A. altissima.

Eric Thiedich
May 5, 2008
Analysis of Defensive Compounds in the Eastern Tent Caterpillar (Malacosoma americanum)

Mentor: Dr. Dean Kahl

Abstract:  The eastern tent caterpillar and its distinctive white silky tent are a common sight in the early spring in the Eastern United States.  The caterpillar is commonly found in the Black Cherry tree (Prunus serotina), who’s leaves contain high concentrations of the cyanogenic glycoside Prunasin.  The caterpillar eats the leaves of the Black Cherry and then regurgitates a mixture containing the cyanogenic compounds as a defense mechanism.  The objective of this research was to develop a method to analyze defensive substances in the Eastern tent caterpillar (Malacosoma americanum).  Caterpillars were collected from Black Cherry trees and stored at -70° C.  The water in the sample was removed by placing the caterpillars in a desiccator for one week.  The dried caterpillar were sliced up and treated with methanol for 24 hours.  The extract was analyzed using High Performance Liquid Chromatography and three major components were observed.  Through peak enhancement and liquid chromatography mass spectrometry, one component was identified as amygdalin, a cyanogenic glycoside found in small concentrations in the Black Cherry leaf.  The substance causing the largest peak could not be identified.  The largest peak appeared to be benzaldehyde, based on peak enhancement.  However, this identification could not be confirmed by LC/MS.

Ari Berk
May 5, 2008
Method for Using High Pressure Liquid Chromatography to Profile Amino Acids in Nutrient Broth

Mentors: Dr. Jeff Holmes and Dr. Victoria Collins

Abstract: A method for HPLC analysis of amino acids was partially adapted and redeveloped for analysis of amino acids in nutrient broth in the Warren Wilson lab. The method as it stands now is unable to separate most amino acids, but it is able to produce multi-peak spectra of amino acid mixtures.

Jorge Lopez
May 12, 2008
Plant Secondary Metabolites and Medicinal Properties

Mentor: Dr. Michael Torres

Abstract:  Many of the important drugs synthesized today originated from plants (Leslie Taylor 2000). Specifically every fourth pharmaceutical has originated from plants (H. Simonsen 2007). Our tropics and local flora contain many plant species that may be of benefit, but have not been studied. Secondary metabolites are organic compounds that are not directly involved in the normal growth, development, or reproduction of organisms. Secondary metabolites of garlic and onions have been used for their medicinal properties since 1550 BC (R. Muoio et al 2004). Research has shown that the garlic and onions contain antitumor, antibiotic, and antiplatelet aggregate properties (V. Lanzotti 2006). Thiosulfinates or more specifically Allicin has been identified as the main contributor of their medicinal properties (Lanzotti). In this experiment Allium species were analysed for thiosulfinate levels using HPLC. The Kirby Bauer method was used to view the antimicrobial strength of five Allium species to determine any correlation between thiosulfinate levels and antibiotic efficacy. Extracts treated with HCl were also used in the Kirby Bauer methods to study the effects of digestion on antibiotic strength.

Camille Prevost
May 12, 2008
Effect of two terpenes on the hemlock woolly adelgid, Adelges tsugae.

Mentor: Dr. Dean C. Kahl

Abstract: The hemlock woolly adelgid, Adelges tsugae, is an invasive pest species that threatens eastern North American hemlock forests. This pest species is also found on western hemlocks but is not a threat. Evidence suggests that some terpenes found in Western hemlock species may deter the hemlock woolly adelgid. Adelgid were collected, while in the active phase, from three sites in Western North Carolina. Ten trees were selected from each site, and four 10 cm branch samples were taken from each tree. Samples were placed in one of three treatment groups receiving α-pinene, or β-caryophyllene, or no treatment. The adelgids were assessed for mortality every two days for a 10 day period. Treatment groups were analyzed using a nonparametric survival analysis. There was no significant difference between treatments at the 95% confidence level. The survival analysis of 90 samples suggests that α-pinene and β-caryophyllene have no effect on mortality of the hemlock woolly adelgid during the active phase.