Natural Science Seminar


Fall Semester, 1999-2000

Sept. 6, 1999, Jessica Buchanan.
Mentor, Dr. Mark Brenner

Abstract:  This study was an attempt to determine if the changing ammonia levels in trout farm effluent would affect the invertebrates  downstream.  When changes in the environment affect stream invertebrates they respond by entering the current and moving  downstream in a behavior known as drift.  In this study, ammonia and drift levels were monitored upstream and downstream of a trout farm located on Sorrels Creek, Haywood Co., NC.  Samples were taken at two hour intervals for a 24 hour period.  Two 24hour trials were conducted.  Regression analysis of the first trial showed no relationship between ammonia levels and total drift levels upstream, however, at the downstream site there was a significant positive relationship between total drift and ammonia levels.  Further regression analysis of the downstream data found a significant positive relationship between ammonia levels and the drift levels of orders ephemeroptera, plecoptera, diptera, oligochaeta, and coleoptera.  There was no significant relationship found between ammonia and tricoptera.  Regression analysis of the second trial, showed there was no relationship upstream between ammonia levels and drift levels, while downstream there was a significant negative relationship between total drift and ammonia levels.  Likewise, there was a significant negative relationship between ammonia levels and drift levels of the orders ephemeroptera, plecoptera, and oligochaeta.  The relationship between diptera and ammonia was not quite significant, and there was no significant relationship between ammonia and tricoptera levels. The data are inconclusive on the effects of ammonia on invertebrate drift because the first trial showed a positive relationship and the second trial showed a negative relationship.  Further research must be conducted in order to better determine what effect ammonia has on invertebrate drift.

Sept. 13, 1999, Courtney Wengrow
The Effects of Different Types of Soil Amendments on Soil pH
Mentor: Dr. Jim Houser

Abstract: This research examined the effects of various types of soil amendments on soil pH. The use of soil amendments is a common practice which preimarily adds organic matter to the soil. Organic matter has various benefits associated with it, most prominent is that of soil fertilization. As soil amendments break down, their elemental constitiuents are incorporated into the soil, changing the soil chemistry. In this study pH levels were collected over a period of two months from a soil treated with various different amendments. The amendments used were: leaf mulch, pine bark, wheat straw, hardwood mulch, ashes, and a control. A t-test was performed between the first and last pH readings for each treatment and showed that all of the soil amendments, aside from the control, had a significant effect on the soil pH. An analysis of variance was performed as well, and showed a significant difference in the pH changes form the ashes compared to those of the other treatments.  The results from the statistical tests suggests that the application of soil amendments has a significant effect on soil pH, and that these changes vary as the treatment varies. However, further research is necessary to ascertain the specific mechanisms by which the soil chemistry was altered.

September 20, 1999, Joel Barto
The Effects of the Kombucha Beverage on Crown Gall Tumors Grown on Potato Discs
Mentor: Dr. Victoria Collins

Abstract:  The Kombucha is a symbiotic association of bacteria and yeast that ferments sweet tea into an acidic tonic.  Kombucha beverage is a tonic believed to cure conditions such as high blood pressure, arthritis, and cancer.  The claim that kombucha will cure cancer was the motivation behind this research.  This project was divided into two parts:  (a.) Observation of the fermentation process.  (b.)  Tumor inhibition bioassay.  The acid production (fermentation) was monitored over thirteen days.  It was found that three strains of kombucha produced varying levels of acid.  The tumor bioassay investigated the effects of kombucha beverage on the growth of Crown Gall Tumors which are initiated by Agrobacterium tumefaciens.  After this pilot study, it was concluded that the effects of kombucha beverage on tumor growth were variable.

September 27, 1999, Joy Frere, Nest-site Selection of the Roseate Tern (Sterna dougallii) on Coastal Islands of Maine
Mentor: Dr. Louise Weber

Abstract:  The Roseate Tern is a mid-sized colonial seabird that breeds on the Northeast coast of North America.  The Common Tern and Arctic Tern are similar seabirds that breed in the same region.  In this study the habitat characteristics of the nest-site of the Roseate Tern is compared to the habitat readily available to the tern, as well as the habitat characteristics of the nest-sites of the Common Tern and the Arctic Tern.  This study was conducted over the course of two summers.
In the summer of 1998, 25 Roseate Tern nest-sites were located on Eastern Egg Rock and 27 on Stratton Island.  A random ground plot was located for each nest-site.  Three habitat characteristics were measured for each nest-site and its corresponding random ground plot: percent vegetation cover within 0.25 m of the nest-site, percent vegetation cover within 0.50 m of the nest-site, and the height of the tallest vegetation within 0.25 m of the nest-site.

In the summer of 1999, 20 Roseate Tern, 20 Common Tern, and 20 Arctic Tern nest-sites were located on Eastern Egg Rock.  For each nest-site, seven habitat characteristics were measured: percent vegetation cover within 0.25 m, number of eggs, visibility of the nest cup, height of the tallest vegetation within 0.25 m, distance to a nest belonging to the same species, distance to a nest belonging to a different species, and the number of nest within 2 m of the nest-site.

Mann-Whitney tests showed that the Roseate Tern significantly selected for more vegetation cover and taller vegetation when compared to the habitat readily available.  Mann-Whitney tests showed that there was no significant difference between the Roseate Tern nest-sites on Eastern Egg Rock and those on Stratton Island.  Student-paired t-tests showed that the Roseate Tern significantly selected for different habitat characteristics than either the Common Tern or the Arctic Tern.  However, the Roseate Tern did not select to be closer to nests of its own species.  When compared to the Arctic Tern alone, the Roseate Tern did not select to have a different number nests within a 2 m circumference of the nest-site.

The knowledge of the habitat characteristics that the Roseate Tern selects for can be used to better manage the vegetation to promote the breeding of this endangered species.

October 11, 1999
Donald F. Collins
Ronald Sebilo-Tibbits
Stephanie Sky Stephens
Video Recording of the Flash Spectrum of the Chromosphere at the August, 1999 Total Solar Eclipse

Abstract: A recent expedition from Warren Wilson College visited Romania in August, 1999 to observe and photograph the August 11, 1999 total solar eclipse.  A high quality consumer-grade color video camcorder fitted with a diffraction grating continuously recorded the spectrum throughout totality. During the few seconds immediately after the start of totality and before the end of totality,  the thin chromosphere, visible beyond the limb of the moon, formed its own "slit".  This enabled the camcorder with its diffraction grating to act as a spectrograph.  Because the chromosphere is an emission region (the continuous black-body of the photosphere is blocked by the moon), the resulting spectrum consists of discrete emission lines as opposed to the continuous spectrum of the photosphere.  This was indicated by the abrupt change in the spectrum from a continuous spectrum characteristic of a black body to an emission spectrum characteristic of the much thinner chromosphere.  The flash spectrum was successfully recorded using the video camcorder/diffraction grating.  The spectrum images have been processed and analyzed for wavelengths.  The presentation will show the videos as well as the wavelength analysis and comparison of the spectrum with common light elements.

The expedition was funded by the Appalachian College Association - Faculty-student research program.

Oct. 25, 1999, Laurie McKenzie, An analysis of using various winter wheat cultivar mixtures to control the disease severity of Septoria Leaf Blotch.
Mentor: Dr. Mark Boudreau.

Abstract:   This project was done in coordination with the TITLE project at Oregon State University.  Septoria leaf blotch disease is a serious concern to wheat growers in the Willamette Valley of Oregon as it can cause dramatic yield losses.  Prior to the 1960s, only occasional losses of economic significance were reported (the septoria wheat diseases). Currently, yield losses attributed to severe incidences of septoria tritici blotch of wheat have been reported in the range of 31% to 53% (also in septoria wheat diseases).  In 1982, worldwide loss due to septoria was estimated to be 9 million metric tons.  This amounted to a value of over $1 billion U.S. dollars.  Under severe epidemics, the kernals of vulnerable wheat cultivars are shrivelled and are not fit for milling.  This study focuses on the use of winter wheat cultivar mixtures to reduce the severity of septoria tritici leaf blotch.  It was hypothesized that growing wheat in cultivar mixtures would slow the disease progress of septoria enough such that the disease expression would not have a substantiative effect on yield loss.  The flag leaf (top most leaf of the wheat plant) is the plants most direct reservoir of nutrients that feed the developing head,thus the loss of photosynthetic ability due to diseased flag leaf area directly decreases filling ability.  Percent disease on the flag leaf, area under the disease progress curve, a whole plant weighted disease figure, and yield were used to determine the effectiveness of the mixtures in decreasing septoria severity.   Mixture effectiveness was defined as the ratio of the mixture disease assment:average of the pure stand components of the mixture being significantly different than one.  The gene-madsen and cashup-stephens mixtures were found to have the only significant mixture effects.  The study also included an analysis of which disease assessment tool was most closely coorelated with yield.  Regressions were used to determine the tightness of fit between the assessment tool and yield.  One of the two flag leaf disease readings had a positive significant regression relationship.  It was found that as disease increased, yield increased as well.  The environmental conditions of this growing season were not highly condusive to septoria tritici leaf blotch development.  It was thought that with little disease pressure, mixture effects may be minimal and/or irrelevant.

Nov. 1, 1999, Walker Young,
Assessment of Methane Production for Feedstocks
Mentor: Dr. James Houser

Abstract: Biogasification is "the biological decomposition of organic matter of biological origin under anaerobic conditions with an accompanying production primarily of  methane and carbon dioxide" (Diaz, 1993).  Methane digestors attempt to isolate the biogasification process and collect the methane gas to be used as fuel energy.
    The objectives of my study were first to produce a burnable biogas using a simple methane digestor design, and secondly to correlate pH and percent volatile solids with the volume of biogas produced.  The first experiment used four feedstocks, cow manure, horse manure, pig manure, and grass clippings. I hypothesized that the manure feedstocks would produce greater volumes of gas than the grass feedstock.  A significant difference was found between the mean volume of gas produced from horse and cow feedstocks when compared to grass and pig feedstocks.  In addition, using linear regression analysis, a positive correlation between pH and volume of biogas was found.
    Because pig manure and grass clippings did not produce a burnable gas I set up a second experiment.  Experiment 2 used four treatments.  Treatment 1 was a control, 2 included a seed solution, 3 included an addition of sodium bicarbonate, and 4 included both sodium bicarbonate and seed solution.  I hypothesized that the treatment of seed solution and sodium bicarbonate would produce a burnable gas.  Analysis through a burn test shows both grass clippings and pig manure producing burnable gas with treatment 2 and treatment 4.
    My results show that without addition of seed solution producing gas with grass alone may not be possible.  Most importantly my study shows the possibility and simplicity of producing biogas as a source of energy on and off a farm.

Nov. 8, 1999.  Angela Meek
A Comparative Behavioral Study of the Effects of Weaning on Warren Wilson College CattleMentor: Dr. Robert A. Eckstein

     The first objective of this study was to compare the behavioral changes during weaning of more experienced mothers (8-10 offspring) to less experienced mothers (2-offspring). The second objective of this study was to compare the behavioral changes during weaning of mothers whose offspring have been removed to mothers whose offspring remained. These two objectives were then broken down into four null hypotheses:

· Young Mothers vs. Old Mothers
-There will be no difference in the amount of ingestions
-There will be no difference in the amount of vocalizations
· Mothers Whose Offspring Were Kept vs. Mothers Whose Offspring Were Removed
-There will be no difference in the amount of ingestions
-There will be no difference in the amount of vocalizations

    The observations took place three times a day, two consecutive days prior to weaning, the actual day of weaning, the third day following weaning, and the fifth day following weaning. The occurrence or absence of ingestions and/or vocalizations was recorded every five seconds within a 2 or 3 minute period of observation for each subject.
     For Young Mothers vs. Old Mothers, Unpaired t-tests and Mann-Whitney Tests revealed that there was no significant difference in the amount of ingestions or vocalizations, resulting in failure to reject the null hypotheses. For Mothers Whose Offspring Were Kept vs. Mothers Whose Offspring Were removed, an Unpaired t-tests did reveal a significant difference in the amount of ingestions for day3 in the comparison of mothers whose offspring were kept vs. mothers whose offspring were removed, thus rejecting the null hypothesis for day3 only.

November 22, 1999, Jamie Ager
The Effect of Grazing Chickens on Pasture Quality.
Mentor: Dr. Victoria P. Collins

Abstract:.  Chicken is now the most popular meat in America. However,  large scale farming has reduced animal welfare and the number of family farms while increasing environmental problems.  Pastured poultry is an alternative for the small farmer that alleviates these problems. Based on a movable floorless pen, the chickens are allowed to graze a new plot daily for fresh grass and insects.
     This project primarily looks at pasturing chickens as a fertilizer.  Organic matter and grass height were tested in control and experimental plots to determine how 44 chickens affected the 12 X 14 space where the pen was each day.   These two aspects of pasture health were measured to determine overall pasture quality.  Data were taken before the chickens were on the plot, one week after they left, two weeks after, and four weeks after.  A taste test was also performed to compare the overall acceptability of  pastured chicken and conventional chicken.
     For organic matter and grass height the effects of time and treatment (pastured vs. control)  were compared by two way ANOVA. Soil organic matter increased in experimental plots (p = .0012) and the interaction between time and treatment was significant (p = (.0325).  Grass height was highly variable and not significant. Taste panelists tended to rate pastured chickens more acceptable by paired t-test than conventional chickens (p = .067). Economic analysis indicates pasturing birds is a sound environmental practice with economic potential for the small farmer.

Nov. 29, 1999, Alysia Greco
The Effects of Grazing on Species Composition and Protein Content of the Warren Wilson Pastures
Mentor: Dr. Mark Boudreau

Abstract: The effects of grazing on species composition and protein content were measured on the Warren Wilson pastures in the spring and summer of 1999. Exclosure plots (10m by 10m) were placed in 5 permanent pastures, which were periodically grazed according to the rotational schedule.  The percent of plot occupied by white clover (Trifolium repens L.), orchard grass (Dactylis glomerata L.), and tall fescue (Festuca arundinacea Schreb.) were measured immediately prior to each grazing event.  This data was gathered two times in three pastures and three times in two pastures.  Protein content of the pasture was determined by taking samples of grass inside and outside permanent fence and sending them to the Department of Agriculture lab in Raleigh, N.C. for analysis.  In addition to protein, acid detergent fiber, dry weight, and mineral composition were analyzed.  Grazing significantly (p< 0.05) increased the percentage of clover and significantly decreased the amount of fescue.  The percentage of orchard grass did not significantly change.  The amount of protein in the grazed grass was significantly higher than the ungrazed grass.  Total digestible nutrients, zinc, and potassium were also significantly higher in grazed grass.  Grazing did not significantly change the percentage of the other minerals measured.  However, grazing significantly decreased the amount of acid detergent fiber and dry matter.  The nutritional studies may have been compromised by the addition of a potassium, phosphorus and micronutrient fertilizer to the grazed grasses.
    The results of this study may implicate that the intensity of grazing and the amount of fertilizer added to the pastures now is appropriate.

Dec.  6, 1999, Amy Frey
The Effect of Improved Pasture Management on Water Quality at Berea Creek
Mentor: Dr. Mark Brenner

Abstract: Runoff from agricultural crop fields, pastures, and feedlots are a major source of non-point water pollution.  New management practices are being implemented to reverse this trend.
    This study compared water quality parameters before and after a one strand high tensile electric fence was built creating a buffer zone around the perimeter of Stokes pasture on Warren Wilson College Farm. In this study, the concentration of ammonia (NH3), total suspended solids (TSS) and, biological oxygen demand (BOD) were measured as indicators of water quality.  In this study the cattle had access to a twenty-foot section of Berea Creek while grazing Stokes pasture. Replicate samples were collected upstream and downstream of the watering area.  The before sampling occurred during the spring of 1999 and consisted of five replicates. Pasture improvements were completed at the end of the April 1999.  Four more data replicates were taken in the fall of 1999.
     A comparison of the amount of TSS upstream and downstream before pasture improvements (spring) had a significant p-value of 0.03. TSS analysis after improvements (fall) was not significant. However, the differences in TSS levels upstream and downstream between spring and fall were significant with a p-value of 0.018, showing the negative impact due to pasture improvements over time.  The concentrations of BOD upstream and downstream were not significant for spring or fall.  The differences between up and downstream between spring and fall were also not significant for BOD.  A comparison of NH3 upstream and downstream before improvements was not significant, but a comparison after improvements was significant with a p-value of 0.01. This is because upstream concentrations were higher than downstream concentrations for all four replicates in the fall.  The differences between the levels upstream and downstream of NH3 for the spring and fall were not significant.

Dec. 6, 1999,  Brookie Brodmerkel
Mentor: Dr. Lou Weber

     The Southern Appalachian Mountain Range is the oldest mountain range in the United States and was never affected by glaciers.  As a result of such a long period of uninterupted evolution, the Southern Appalachian Mountain range has the highest diversity of Salamanders in the world.  Although we live in a salamander diversity hotspot, there has been a rapid decline in all amphibian species.  At the time, 25% of all amphibian species are concidered either threatened or endangered.  Collecting an inventory of salamander species and thier habitat characteristics can give insight into population diversity and abundance.  The first objective was to compile a salamander inventory list on five streams on Warrn Wilson property and one stream on the Warren Wilson adopted Boogerman Trail in the Cataloochee Wilderness Area.  The second objective was to determine the major characteristics and site quality of salamader habitats.  The method of collection was a Visual Encounter Survey.  Habitat Factors were collected at each site.  Linear regression was used to shoe the relationship between habitat factors and athe total amount of salamanders inventoried.  A Chi-square test was performed to show the preference of substrates by the salamanders.  Results indicate that there was a correlation between the total percentage of herb cover and the total amount of salamanders and the pH of water and the total amount of salamanders.
Further monitoring studies on Warren Wilson property needs to be done so any fluctuations in populations can be assessed.  Act locally, think globally.

December 13, 1999, Matthew Ransom
The effects of Achillea millefolium on clotting time as measured by the APTT test.
Mentor: Dr. Victoria P. Collins

Abstract: Achillea millefolium is a perennial herb traditionally used to treat wounds.  Blood is shown in preliminary tests to coagulate more quickly upon intravenous injection of achilleine, a water soluble hemostatic agent in yarrow.   The purpose of this experiment is to use the activated partial thromboplastin time (APTT ) assay to measure the effects of a water soluble extract of Achillea millefolium on clotting time.  Four treatments,  calcium, calcium plus tannic acid, calcium plus yarrow extract, and calcium plus buffer, are used.  The test is measured in seconds and is conducted blind.  A single factor ANOVA results in a p value less than 0.005 indicating a significant difference between the treatments.  A post hoc ANOVA, Tukeys analysis, reveals a significant difference between the calcium and the calcium plus yarrow extract.  A significant difference between the calcium plus yarrow and the calcium plus tannic acid also exists.  These results indicate an anticoagulant effect of the water soluble extract of Achillea millefolium as measured by the APTT test.  This is an unexpected result because possible anticoagulent properties of yarrow are due to coumarins, fat soluble vitamin K inhibitors. The APTT test measures the intrinsic pathway of blood coagulation.  The anticoagulant properties of yarrow  therefore can be said to have an effect in the intrinsic pathway.   The clot enhancing properties of yarrow may be active in other parts of the blood coagulation pathway not measured by the APTT test, such as platelet aggregation and in the extrinsic pathway.