September 7, 1998
Donald F. Collins, PhD
Professor of Physics, Warren Wilson College
Abstract: As the expedition is planned to view the August 11, 1999 total solar eclipse in Romania, a particular spectroscopic experiment is planned.  The eclipse will be photographed using a video camera fitted with a diffraction grating in order to view the spectrum of the solar photosphere as well as the chromosphere.  Only during the few seconds at the beginning and end of totality is the thin chromosphere visible.  This is indicated by the abrupt change in the spectrum from an absorbance spectrum to a rare emission spectrum.  The presentation will include the geometry of all types of eclipses as well as demonstrate video solar spectroscopy and emission spectroscopy.

Click here for pictures of Romania

September 14, 1998
Jim Eikenberry

Abstract: There are two structurally different stands of baldcypress (Taxodium distichum) (this should be italicized)  on the Warren Wilson College forest.  Despite observed differences in the diameters and heights of the baldcypress in the two stands, the age structure of the two stands was hypothsized to be the same.  Tree-ring analysis, the counting of annual rings of the trees from increment cores, was used to gather data that would test this hypothesis. The data that were gathered and analyzed did not support the
hypothesis.  The data showed varying age structures between the twostands and within the stands themselves.  However, it was believed that these data did not reflect the true age structure of the stands.  Additional field tests were devised to attempt to determine the true age structure within both of the stands.  Results from these preliminary tests show that the Pool stand did in fact have at least two different age classes in it.  And the Pumphouse stand was even-aged.

Sept. 21, 1998
Sunshine Liberty Brosi
Mentor: Dr. Mark Boudreau

    Increasing evidence that global warming will create changes in ecosystems water supplies has created the need for more information on plants resistances to water stress.  During the summer of 1997 I studied the degree of resistance to water stress in tree species at the Boyce Thompson Insitute for Plant Research at Cornell University.
    Cavitation vulnerability, a method of measuring water stress resistance, expresses the decrease in hydraulic conductance after subjection to varying pressures.  I measured cavitation vulnerability of shoots and roots of red maple, Acer rubrum, and sugar maple, Acer saccharum, by starting with the saturation point of the system and measuring the decrease in hydraulic conductance, water flow in grams per minute, at different pressures.
    I found that red maple roots and shoots of similar sizes had similar rates of cavitation vulnerability.  However, sugar maple roots were more vulnerable to cavitation than the shoots of equivalent sizes.
    In addition to this study, I completed two technique development studies, one of which measured cavitation vulnerability on northern red oak.  I also attempted a study involving the dying of vessels of stems from trees on both wet and dry sites at Warren Wilson College.

Sept. 28, 1998
Jon Stockdill
Mentor: Dr. Frederick W. Solomon

    Three puzzles were examined using three methods of analysis.  The puzzles were analyzed geometrically, numerically, and algebraically.  Geometrically, the puzzles were looked at visually as a hierarchy of motions.  The basic motions are the individual motions of the puzzle, and higher order motions are compositions of the basic first order motions.  Numerically, the puzzles were examined using C++ algorithms with Microsoft Developer Studio as the compiler.  The C++ algorithms not only modeled the puzzle, but also solved it.  Theorems were proved using Abstract Algebra techniques to show what starting positions are able to be solved.  The puzzles are solved when the blocks are in ascending order from left to right and top to bottom.

    The NxN puzzle is an NxN grid containing N2  - 1 blocks; the most common puzzle of this type is the 4x4 puzzle, or the fifteen puzzle.  The one block that is removed allows the player to slide the adjacent vertical or horizontal blocks into the space.  The basic first order motions of this puzzle are the sliding of the individual pieces into the space’s position.  The C++ algorithms were used to produce an algorithm that will use higher order motions to solve any puzzle.

    The sliders puzzle is a variant of the NxN puzzle in which the space is not removed.  The rows and columns are slid left or right and up or down accordingly.  When a row or column is slid the piece that is moved out of bounds is placed in the vacant space created by the motion.  These motions are the first order motions of this puzzle.  The second order motions solve the puzzle.

    The last puzzle, triangular torus puzzle, is 16 equilateral triangles stacked on top of one another to form one large equilateral triangle.  This puzzle is a WWC Math Department original, and its first order motions are motions along the positive and negative diagonals and the horizontal rows.  The motions wrap around in a similar manner as the sliders puzzle, which might be thought of as a square torus puzzle.

Oct. 5, 1998
William Hamilton
Mentor: Dr. William C. Davis

     Oriental bittersweet (Celastrus orbiculatus) is a woody vine that has invasive characteristics.  After its introduction from Asia in the 1860's, oriental bittersweet became a popular ornamental in the North East United States.  It is well know for its abundant orange berries that stay attatched to the stem throughout the winter.

     The characteristics which make oriental bittersweet desirable for landscaping are also responsible for its competitive success against the native plants of North America.  The absence of natural controls such as disease and insects allow for its resilient and vigorous growth and its growth habits give the vine capabilites to demolish large stands of timber.  Humans have favored oriental bittersweet by transporting it across the continental United States and encouraging its cultivation.

     Although the dangers of oriental bittersweet have been realized by foresters for more than thirty years, the Natural Resources Crew only recently realized the enormous problem it poses for the forests of Warren Wilson College.  Hoping to find a solution, Anthony Dowdle conducted a seminar in 1997 explaining the effects of Garlon 3A, an herbicide, on the cut stems of oriental bittersweet.  He found that an application of fully concentrated Garlon 3A was effective during the growing season.

     I was inspired to continue Dowdle's research on the relationship between oriental bittersweet and Garlon 3A.  My objective was to find the lowest concentration of the herbicide that would effectively kill the roots systems during the winter. Concentrations of 12.5%, 25%, 50%, and 100% were applied to the cut stems of oriental bittersweet in January, 1998. After a full growing season, I collected the results.  I found that all of the concentrations of Garlon 3A were not effective for completely killing the root systems of oriental bittesweet during the dormant season.  This can probably be explained by the decrease in metabolic activity in plants during the winter.  The slow momvement in the phloem did not allow for complete distribution of the herbicide.

     This study was practical and useful. Because the root systems were not entirely killed, I recommend that Garlon 3A not be applied during the dormant season.  Living roots have the potential to sprout and to support the infrastructure of other healthy vines.  If a landowner's only option is to use the herbicide during dormancy, a 25% solution would probably be adequate.  A 25% solution would prevent the tips from sprouting, it would cost less than a 100% solution, and it would expose the environment to a much smaller dose of the herbicide.

Nov. 9, 1998
Steven Shaper
Mentor: Dr. William C. Davis

     The purpose of this study was to measure the effects of a prescribed fire on an overstory hardwood stand on Jones Mountain.  Prescribed burning is a management tool used on Warren Wilson College Forest to top-kill invasive, exotic species as well as for other objectives.  In this study the effects of prescribed burning were determined by examining the percentage of cambium that died as a result ofthe fire.  11.6% of the trees in the stand were top-killed as a result of the fire.  The average cambium death for all of the trees was 59.7%.  The average dbh (diameter at breast height) of the trees that were top-killed was significantly smaller than the average dbh of the trees overall (p=0.0079).  To see if cambium death varied by species, the dbhs of two different species were constrained and the % cambium death of the dbhs between 5cm and 10cm in yellow-poplar and flowering dogwood were compared.  The % cambium death in flowering dogwood was significantly larger than the % cambium death in yellow-poplar (p=0.0304).  Variation in % cambium death at different dbhs was analyzed within the predominant species, yellow-poplar.  There was a linear regression between the % cambium death and the dbhs for yellow-poplar (p<0.0001,r2=0.3302).
    From this data there appears to be a correlation between % cambium death and tree species as well as dbh.  As a result of this information the Natural Resources Crew should limit prescribed burns to areas with severe invasive species problems and to stands with certain average dbhs and species composition.

Nov. 16, 1998

Mentor: Dr. Robert A. Eckstein.

 Piglets seem to increase their vocalizations when they are restrained, as well as when they are castrated.  The purpose of this study was to determine what bahvioral changes are due to the actual castration process as opposed to the restraint.  Thirty two 10-day-old piglets were divided into two groups; those that were restrained and castrated, and the control group - those that were restrained but not castrated.  The average number of squeals and screams made during the procedure were significantly higher in the group of castrated piglets.  The average number of grunts and total vocalizations, however, were not different between the two groups.  Neither the average number of grunts, squeals, total vocalizations, nor tail twitches for the first minute after the procedure were significantly different between the castrated piglets and the control piglets.  The results indicate that castration does significantly increase the number of squeals and screams of piglets but does not cause significant changes in vocalizations or tail twitches after the procedure between the two groups.  Total number of vocalizations was not a true reflection of piglets' responses to the environment; it did not reflect the significantly higher number of squeals and screams made by the castrated piglets during the procedure.

November 23, 1998
Lissa Veilleux
The Effect of Intercropping on Early Leaf Spot of Peanuts

Mentor: Mark A. Boudreau

     Early leaf spot, caused by the parasitic fungus Cercospora arachidicola, is the one of the most economically devastating diseases of peanut (Arachis hypogea) both locally and globally (Hassan and Beute,1997).  It occurs everywhere that peanuts are grown and all peanut cultivars are susceptible to the fungus.  Yield losses of 10-50% are common due to the effects of early leaf spot, and yield losses of up to 70% have been reported (Johnson and Beute, 1986).  Early leaf spot is generally controlled through crop rotation, peanut debris destruction, and fungicide applications.  The latter method is the most effective, but spray programs are expensive and have been found to induce resistance in certain strains of C. arachidicola.  Crop rotation and destruction of peanut debris are commonly practiced together but are not as effective as spray programs at controlling early leaf spot (Shokes and Culbreath,1997). Consequently, there is a need for research into alternative methods of early leaf spot control.
    Intercropping has long been associated with disease control but often without strong empirical evidence to support such an association.  Studies which have been done emphasize that the effects of intercropping on disease is often site specific and difficult to predict and that new intercrop combinations should be studied before making recommendations to growers (Boudreau and Mundt, 1997; Coolman and Hoyt, 1993).  There are several mechanisms of disease alteration that have been proposed.  Simplistically, they can be categorized into those due to the presence of the non-host intercrop or those due to density (Boudreau and Mundt, 1997).
    The objective of this study is to first determine if intercropping has any effect on the severity or progress of peanut early leaf spot and if so to determine if the effect is due to the presence of the intercrop or to density.
    Three treatments - a high density peanut monocrop, a low density peanut monocrop, and an intercrop of peanuts and corn - were inoculated with early leaf spot and evaluated for severity and progress of the disease.  Severity was analyzed using AUDPC (area under the disease progress curve), and progress was analyzed using rate of disease progress.  The AUDPC and rate of disease progress for the three treatments were compared at the p < 0.05 significance level using a one factor ANOVA.  The results of this study indicate that intercropping does have an effect on severity of peanut early leaf spot but not on progress and that density was the factor responsible for the effect on severity. 

November 30, 1998
Mischa Hartman Suchanec

The Relationship Between Calcium Concentration in Stream Water and
Population Growth and Size of the Amphipoda Gammarus

Mentor: Dr. Mark Brenner


     Calcium has been observed to be highly variable in content level among water sources and is thought to be one of the strongest affecting variables on population distribution of freshwater organisms (Brown 1971).  The Amphipod Gammarus is one freshwater invertebrate organism that appears to be limited to water sources of higher dissolved calcium concentration.  There are many other variables present in the natural freshwater sources that are directly correlated to calcium, and therefore make the limiting properties of the nutrient ambiguous. The purpose of this research was to attempt to completely isolate calcium as an aquatic variable and observe its effects on the population growth and individual mass of the Amphipod Gammarus population. It was hypothesized that as the calcium concentration increased, both the population size would increase and the individual amphipod mass would increase.
     Six artificial, recirculating stream systems were created and randomly selected for treatments; half as control systems and half as calcium treated (to raise concentration to 25 mg/L) test systems. At the conclusion of five weeks, data was collected and analyzed using a statistical t-test. The data revealed no significant difference between population size or between individual amphipod weight when compared between treatments. These results did not support the hypotheses and contradicted the "conventional wisdom" regarding calcium roles in aquatic environment as a limiting factor to these invertebrates. 

Dec. 14, 1998
Jon Hasfjord


Mentors: Dr. C. L. Swendsen and Dr. Deborah Shepard.


    The purpose of this study was to determine whether or not the mucus of Desmognathus ochrofaeus, the Mountain Dusky salamander, has any detectable antimicrobial properties.  Salamanders are small nocturnal amphibians that inhabit fast running streams, ponds, or damp terrain.  Most salamander research deals with the deadly toxins some species employ to repel predators such as raccoons or shrews.  Long term research is difficult with individual salamanders as the researcher must toe clip the animal.  Banding the salamander will cause the animal to drop the banded limb as a defensive mechanism, much like the tail of a lizard.  Traditional marking with paint or non-toxic marker may kill the salamander because they breathe through their skin.  Even toe clipping is short term as the salamander will regenerate any limb within weeks of the amputation.

    A total of seventeen Mountain Dusky salamanders were used in this research.  The antimicrobial effect was measured by the size of the zone of inhibition the mucus produced when placed upon a plated lawn of bacteria.  Three experiments gave positive results for antimicrobial properties while using mucus from four salamanders.  Eighty one experiments showed negative results for antimicrobial properties.   All experiments showed an inherent bacteria living in the mucus of the mountain dusky salamander.

    A barrier experiment was run with three salamanders to test the physical properties of the mucus.  The mucus is known to be a polypeptide mesh.  A positive result would indicate that perhaps the mucus is a physical barrier to bacteria.  Five experiments were run with three positive results, one negative result, and one unusable result.

    A conclusion could not be made as to the antimicrobial propertiesof mountain dusky salamander mucus due to no identification of individual salamanders during the trials. Preliminary experiments suggest that the mucus of the mountain dusky salamander is a physical barrier to bacteria.

January 25, 1999
Wairimu Wamburu


Mentors: Dr. Lee Swendsen & Dr. Deborah Shepard


To avoid the spread of bacterial infections through hand contact, proper hand washing techniques have to be exercised.  These involve the use of water, preferably hot, an effective antibacterial soap and vigorous
rubbing to rid the hand surfaces of bacteria.  Different kinds of antibacterial soaps can be obtained in the market, at different prices.  Some, however, have been speculated not to contain the antibacterial contents required for the soap to be effective.

This study focuses on two soaps - "pink" and "blue", both used at Warren Wilson College, and compares their antibacterial effectiveness by determining the number of bacterial colonies destroyed by each soap.  The "blue" soap has the term antimicrobial in its name ( Antimicrobial Hand Cleanser) while the "pink" soap, referring to Champion Pinky, does not have the terms antibacterial or antimicrobial in its name or list of contents.  Media plates, containing MCA agar were used to sample individuals hands before and after they had washed their hands with either the "blue" or the "pink" soap.  The total bacterial counts were then obtained for each soap and this data was used to investigate the effectiveness of the two soaps, first by calculating total bacteria destroyed by either soap, and then determining if one soap destroyed more bacterial colonies in comparison to the other.

Results from this study showed a significant difference in the number of bacterial colonies destroyed after the individuals had washed their hands with either soap.  There was, however, no significant difference in the amount of bacteria destroyed by the "pink" soap vs. the blue soap.

February 1, 1999
Colleen Rockstroh

An Assessment of the Bioactivity of Herbal Extracts

Mentor: Dr. Dean C. Kahl

    Throughout history, people have tried to combat insects, using methods ranging from the performance of magical acts to systemic insecticides which translocates the insecticidal chemicals to every cell in the plant body.  Concern about the use of synthetic insecticides has heightened interest in the study of plants which possess insecticidal properties.

    The US Office of Technology assessment in 1986 stated that less than 10% of the 500,000 to 750,000 species of higher plants on Earth had been analyzed for their chemical constituents.  In researching plant species which produce insecticidal compounds, a mass-screening of plant material for lethal bioactive compounds is the most logical first step.  Researchers need a quick, easy, and inexpensive bioassay for lethal bioactive compounds.

    My research focused on utilizing an Artemia salina lethality protocol to evaluate the bioactivity of herbal extracts made from Artemisia absinthium, Nepata cataria, and Chenopodium ambrosioides.  Herbal extracts were made by boiling one gram of dried plant material with 100 mL of solvent (deionized water or 95% ethanol).  These extracts were evaluated at three treatments of 1000, 500 and 250 microliters of extract added to five milliliters of brine solution for the water extract of the plants and solvent controls; the ethanol extracts were evaluated at four treatments:  1000, 500, 250 and 100 microliters of extract added to five milliliters of brine solution and solvent controls.
    My null hypothesis for this experiment was that there would be no difference between the herbal extract treatments and the solvent controls in the number of survivors of Artemia salina in a standard brine solution with a critical P-value of less than 0.05.  This null hypothesis was rejected for the deionized water extracts of Nepata cataria at the 1000 microliter treatment (P=0.04).  For the rest of the treatments in this species and the other two plant species for both solvents, the null hypothesis failed to be rejected.

Feb. 8, 1999
Jones Smith

Applications of the Infinite Server Queue Model

Mentor: Dr. Frederick Solomon

The Model explored in this seminar is a queue, or a waiting line like that at a cafeteria. Unlike a cafeteria that has only one or two servers the infinite server queue has an infinite amount of servers. An example would be a city park, where upon entering, the park patrons are instantly being served.
The infinite server queue model can be applied to many real world situations. Data were collected in this experiment from systems that were believed to fit the model. The data were then analyzed and compared to expected values from the data. Observed values were compared to expected values with the Chi squared test for goodness of fit.

March 1, 1999
Galen Eldridge

Effect on the Swannanoa River by Warren Wilson College: Water Quality Assessment Using a Macroinvertebrate Biotic Index

Mentor:  Dr. Louise M. Weber

The Swannanoa River is important ecologically (Southern Appalachian Man and the Biosphere [SAMAB].  1996.  Southern Appalachian Assessment: Aquatic Technical Report. Report 2 of 5.  Atlanta, Georgia:  U.S. Department of Agriculture Forest Service.  Southern Region.), and has had problems in the past (North Carolina Department of Environment, Health, and Natural Resources [NCDE]. 1994.  Basinwide Assessment Report Support Document:  French Broad River Basin.).  Because the Swannanoa will probably face increasing demands from rising human population numbers and development in Western North Carolina, it is important to continually monitor the Swannanoa River for water quality.  The primary advantage of using macroinvertebrates to monitor water quality is that bottom-dwelling insects maintain stable positions in the aquatic environment.  The invertebrate community can reflect long-range shifts in environmental quality, while chemical analyses reflect the quality of the water only at the time samples are taken (McCafferty, W.P.  1981.  Aquatic Entomology. Science Books International.  Boston.).  No rigorous study had previously focused on biological testing to examine the effect of Warren Wilson College on the Swannanoa River.  My first objective was to assess the impact of Warren Wilson College on the Swannanoa River using a qualitative collection method for macroinvertebrates by sampling just upstream and downstream of the property.  I used the revised North Carolina Biotic Index [NCBI] (Lenat, D.R.  1993.  A biotic index for the southeastern United States:  derivation and list of tolerance values, with criteria for assigning water quality ratings.  Journal of the North American Benthological Society.  12:  279-290.).  My second objective was to compare the results from the NCBI with those achieved using two other indices, the Hilsenhoff Biotic Index (Hilsenhoff, W. L.  1988.  Rapid field assessment of organic pollution with a family-level biotic index. Journal of the North American Benthological Society.  7:  65-68.) and the Alabama Water Watch Index (Deutsch, W. 1993.  Unpublished document. Stream Quality Assessment Form.  Alabama Water Watch.  Auburn University.).

    From 29 August to 27 September 1998, upstream and downstream sites were sampled three times using a qualitative multiple habitat approach.  This involved two people working for 30 minutes washing substrate into a D-net from all microhabitats within a 20 m stretch of river.  The substrate was then examined for macroinvertebrates, which were removed to 70% ethanol.  In the lab, the macroinvertebrates were identified to the lowest possible taxon using An Introduction to the Aquatic Invertebrates of North America (Merritt, R.W. and K.W. Cummins.  1996.  An Introduction to the Aquatic Invertebrates of North America.  Kendall/Hunt Publishing Company.  Dubuque, IA.).  A biotic or cumulative index value was calculated for each sample.  Using the NCBI, the average biotic index values for upstream (4.89) and downstream (4.65) classified both sites as good water quality.  Averaging the biotic index values from the HBI, the upstream site was classified as good water quality (average biotic index value = 4.42), and the downstream site as very good (3.93).  Using the AWW, the average cumulative index values for upstream (15.7) and downstream (13.7) classified water quality as fair.  No trends by date, and no significant difference (p > 0.05) were found in water quality from upstream to downstream of Warren Wilson College using the NCBI, HBI, or AWW.  In comparing the three indices, variation was observed between water quality assessment, and number of idividuals and number of taxa appropriate for use.  According to this study, Warren Wilson College has no effect on the Swannanoa River.  NCBI  tolerance values were derived from southeastern streams, a high number of individuals collected were appropriate for use in the NCBI and a high number of taxa were used to calculate the biotic index values. Thus the NCBI seemed to be the preferred index for the Swannanoa River. The results of this limited sampling may not reflect the long term trend of water quality upstream to downstream of Warren Wilson College.  More samples over time in future studies might clarify upstream to downstream trends. 

March 22, 1999
Charla A. Archie

An Observational Study of the Behavior of Felis Rufus (Bobcat) at the Western North Carolina Nature Center Before and After an Environmental Change

Mentor: Dr. Robert Eckstein

The Western North Carolina Nature Center has three bobcats on exhibit, one 9 year old male named Sam and two females just over 4 years old named Goldie and Gray. An individual who bought him from Santa&rsquo;s Land Zoo in Cherokee donated Sam and a female bobcat to the Center in May 1993. The two females at the Nature Center are the offspring of Sam. The three bobcats lived in a small, round, concrete cage until April 23, 1998. They were then moved to a larger grass bottom enclosure. I hypothesized that the behavior of each bobcat will change with the change in habitat.

I observed the bobcats from three to four p.m. on Mondays, Wednesdays, or Sundays from December of 1997 to November of 1998.

I used Focal Animal Observation to study each individual in ten-minute increments. I used Instantaneous Time Sampling to measure the states of Down, Sitting, Active, and Non-visible in 30 second sample increments. I used Continuous Recording to measure the events of Oral Grooming, Scratch Grooming, Allo Grooming, Direction Changes, Circles, and Spraying. I analyzed my data using the Mann Whitney Test. Each individual&rsquo;s events decreased, but not all were statistically significant, while their activity level did not decrease significantly.

Mar. 29, 1999
Gene Scerbo

Slime-Blotch Disease among Coral Reef Fish of the Bahamas

Mentor: Dr. Paul Bartels

In the last ten years, a series of strange new fish diseases have caused massive fish kills and human health problems from the Chesapeake Bay to South America.  These diseases are often related to environmental degradation, so incidences of new disease require close monitoring. In the summer of 1997, a WWC field class noted reef fish in the Bahamas with black spots that looked like small patches of mildew.  The spots were tentatively identified by a fish pathologist as slime-blotch disease, a newly recognized fish malady from Florida to the Caribbean.  In an effort to document the presence, distribution, and virulence of this disease in the Bahamas, a survey of reefs in the Bimini and Berry Island groups was conducted in the summer of 1998.  Collected specimens were analyzed, and slime-blotch was confirmed as the disease in question. The reef surveys allowed me to determine which species and which size  classes were being affected most heavily, and to measure the extent of the infestation on infected species.  I also initiated a preliminary assessment to measure potential behavioral effects of the disease. The results suggest that slime-blotch is widespread on certain common herbivorous reef fish, although the infections were mild and seemed to produce little morbidity.  The potential for this disease to increase rapidly , and its association with major fish kills in the Florida Keys (Landsberg 1995, Tropical reef-fish disease outbreaks and mass mortalities in Florida, USA: What is the role of dietary biological toxins? Dis. aquat. org. 22:83-100), suggests that ongoing monitoring would be called for even in the relatively pristine waters of the Bahamas. 

April 5, 1999
Serah Overbeek

Soil pH and Soil Moisture Preferences of the Salamander, Desmognathus

Mentor: Dr. Louise Weber.

There has been a world-wide decline in amphibain populations in the last decade.  At the time at least 25% of all amphibian species are considered either threatened of endangered, and the numbers continue to rise.  This is due to a combination of factors including amphibian sensitivity to environmental pollution, and increased habitat loss.  The Southern Appalachian range contains the highest diversity of amphibian species in the world, placing Warren Wilson in a prime area for doing salamander research.  Attempting to determince the factors that influence salmander distribution can give insight into population abundance and diversity.  In this study, soil pH and moisture preferences of the Mountain Dusky salamander were tested using three replicate chambers. Three levels of pH and three levels of moisture were tested simultaniously, giving nine possible combinations.  Salamanders were placed in chambers containing all nine soil types and location of the salamanders were recorded at the end of three hours.  Salamanders were tested one at a time and each salamander was used only once.  Results indicate that these Mountain Dusky's significanly chose the high pH treatment (pH 7.0), and the high moisture treatment.  However, it was not possible to determine which factor, pH or moisture, had a larger influence over how the salamanders distributed themselves.  Further monitoring of salamander populations on Warren Wilson property needs to be done so that any fluctuations could be assessed.  A survey of diversity, and estimates of abundance, as well as a descriptive study of their habitat would be a necessary starting point.  In the process of so much construction and human impact in this area, it's important that we don't jeopardize salamander populations.

April 12, 1999
Stacie Greco

The Pyrolysis of Waste Plastics to Obtain a Fuel

Mentor: Dr. Dean Kahl

     The disposal of plastic wastes is a continuing problem because plastics constitute 20% of the volume of municipal solid wastes in the US (Warren and El-halwagi, 1996).  During the oil crisis in the seventies,  there was much enthusiasm for using plastic wastes to produce fuels.  The wastes were pyrolyzed, resulting in substances which could be used as fuels or as chemical feedstock. Although  some high tech research is still being conducted, interest in the recovery of fuel from plastics decreased along with the price of oil.
     The object this research is to reclaim fuel and chemicals from plastic wastes by pyrolysis. The pyrolysis was carried out using a low tech vacuum distillation apparatus.  I wanted to determine the feasibility of  recycling and reclamation programs in impoverished areas.
     Several experiments were carried out with polystyrene due to its abundance and the lack of an existing market for recycled polystyrene. The pyrolysis was carried out in the presence and absence of an alumina catalyst.  The products were analyzed using gas chromatography.
     The boiling point data suggests that the distillate is a mixture. The chromatograms from the experiments done without a catalyst suggest that styrene is the predominant product (84%). The chromatogram from the experiment performed with the alumina catalyst imply that the product is a relatively complex mixture with unknown composition.

May 10, 1999
Jessie Rue Ritz Dulberger

The Effects of Phosphorus on the Weight and Population  of Gammarus in an
Artificial Streams

Mentor:  Dr. Mark Brenner

There has been debate over which nutrient limits the abundance of invertebrates.  Fishing literature and some scientific studies believe that calcium is the limiting nutrient for invertebrates in hard water streams.  Mischa Suchanec's natural science seminar (unpublished 1998) suggested that  the increase in calcium in an artificial stream setting, did not significantly increase the population or weight of Gammarus. Thus calcium was not the limiting nutrient for the abundance of invertebrates in hard water streams. It has been observed in many studies that phosphorus  increases algal growth in water ecosystems.  Studies also suggest that the increase in algal growth is  correlated to an increase in the abundance of invertebrates.  Thus phosphorus is thought to be the main limiting factor of the distribution of freshwater invertebrates in hard-water streams.  It is possible that phosphorus contamination ( thus an increase of phosphorus) in limestone bedrock in watersheds is the reason for an increase in the abundance in invertebrates.

The  objectives for this study were to examine how the addition of phosphorus affects the population and weight of Gammarus.  (Gammarus is the small freshwater crustacean that was used in this study.)   I found that there was no significant difference in the weight of adults and the population of both the adult and offspring Gammarus with the addition of phosphorus.