As part of the Duke GALS NC program, the girls conduct science experiments throughout the second week of their backpacking trip. They then give short speeches about their work before doing poster presentations.
The 2017 Duke GALS NC did experiments on snail activity, tree types, fungal biodiversity, stream contamination, soil quality, root thickness, indicator species, and organism growth on trees.
Check out their full speeches or learn about their research below.
Research question: How does contaminated stream water differ from non-contaminated stream water chemically?
Hypothesis: Contaminated stream water will have higher levels of phosphate, nitrate, temperatures, and turbidity. It will have a low pH level.
Process: “My method for collecting my data was chemically testing the water. I used stream water for the non-contaminated water and simulated contaminated stream water using a mixture of soil from a fire pit and stream water. I used soil from a fire pit because more people use it, which indicates contamination.”
Results: “Based on the data found, contaminated water is more toxic chemically. I found that in contaminated water, there was a temperature of 20°C, pH of 7, turbidity of 1,000 JTU, nitrate of 10 ppm, and phosphate of 2.5 ppm. Non-contaminated water had a temperature of 18°C, a pH of 7.5, turbidity of 0 JTU, nitrate of 3 ppm, and phosphate of 0 ppm. While it can naturally be assumed that contaminated water can be more toxic, this study proves that it is really more toxic than non-contaminated water…The chemical levels found in contaminated stream water can help differentiate non-contaminated and contaminated stream water. ”
Research question: Are snails more active in the daylight or night? Where are they most active–on trees, dead leaves, live green leaves, rocks, or organic matter?
Hypothesis: I think snails are more active in the daylight on trees than dead lives, live green leaves, rocks, and organic matter.
Process: “To test my hypothesis, I collected two snails of the same size, same species from different areas. Subject A was found on a deciduous oak tree, while Subject B was found on a rock in a camp fire pit. From 2:55 P.M. to 3:29 P.M., I placed Subject A and B on five different surfaces for six minutes each to record how active each snail in the daylight was. I measured in inches how far they moved from the beginning to the end of the six minutes…Then I recorded their movements from 9:35 P.M.-10:09 P.M. to see if the snails were more active at night than in daylight.”
Results: “From my gatherings and recordings, I concluded that Subject A was most active in the daytime on trees, while Subject B was more active in the night on organic matter.”
Research question: Is there a difference in fungal biodiversity between trails and campsites?
Hypothesis: Due to heavier human presence through contamination from food, litter, human waste, campfires, and tents, campsites would have less fungal biodiversity than that of trails.
Process: “For this experiment, I used circular sample plots with a radius of six meters recording all fungi within the plot. I did eight of these plots along trails at random points and eight plots at campsites at three different campgrounds in the backcountry with 2-3 plots per camp we stayed at. In total, I took 16 sample plots and saw over 15 kinds of fungi.”
Results: “There was no significant difference in biodiversity between trails and campsites. However, according to my data, there tended to be more fungi in sheer numbers along trails rather than within campsites.”
Research question: “What types of tree species are near streams vs. not near streams?”
Hypothesis: I believe that there are more rhododendron trees grown near streams than inland.
Process: “I gathered my data by using different areas of streams when we passed by them on our trails. I observed the trees near the streams. Then I would go a few feet away from the streams and observe the other trees…I had 18 subjects and nine species of trees, which included rhododendron, maple, pine, beech, elm, coniferous fir, ash, and oak.”
Results: “My conclusion was that rhododendron trees grow more near streams because they need their soil to be really moist, and they need it to keep their leaves waxy, which provides them with water. There is more diversity inland than near streams because some species need neutral soils so the soil is not too dry or too wet.”
Research question: How does water quality affect the number of indicator species in an area of water? (Indicator species are organisms that are extremely sensitive to changes in water quality and can only survive in clean water.)
Hypothesis: The better the water quality, the more indicator species will be found in that area.
Process: “The indicator species I chose to look for were mayflies, stoneflies, caddisflies, and salamanders…To test for water quality, I did several chemical tests on three different areas of streams. In each area, I tested temperature, pH, dissolved oxygen, phosphate and nitrate concentrations, and turbidity. After completing the tests, I searched for indicator species and documented how many types of indicator species I could find and the total number of indicator organisms I could find in each area.”
Results: “As the water quality got better in each area, the total indicator organisms found increased by exactly seven. As the water quality increased, the general number of indicator taxa went up. Based on my data, I can conclude that there is a correlation between water quality and the number of indicator species in an area of water.”
Research question: Based on temperature and location, which soil is most sustainable for plant life, and which soil has the best consistency and is in the healthiest state?
Hypothesis: The soil with barely any human activity located in Pisgah National Forest will have a deeper topsoil. That means that the soil is the best type to support the life of plants.
Process: “I dug up holes of up to about 10 inches deep and took samples of soil. In Pisgah, I took it from where a lot of trees were growing and a lot of wildlife basically and where we would not go near. My other sample was where we were walking and very close to it. The soil unbothered by humans in Pisgah was very dark and rich, and it was more broken down than the one that wasn’t affected by humans. The soil at home back in Fuqyay-Varina was unbothered. It was dark and rich, but it was a lot drier than both the Pisgah soils. The one affected by humans here in Fuqyay was a lot grainer, and it had a lot larger particles.”
Results: “Because Pisgah has more precipitation and good weather overall, its soil with or without human activity had pretty good results. The soils remained moist and weren’t filled to capacity with rocks and undecomposed organic matter. On the other hand, in Fuqyay-Varina, the soil had less of the good qualities. It was moist from past rains but was overall much grainer and had many more rocks in both locations. I have concluded that my hypothesis is correct. The soil with no human activity in Pisgah National Forest had the best quality soil for plant life and organic matter.”
Research question: What is the difference in abundance of moss, lichen, and fungi in deciduous trees?
Hypothesis: Deciduous trees have more moss or fungi than lichen along their trunks.
Process: “I had six plots, three from each of the two campsites we visited. Each plot had dimensions of 10 m by 10 m and approximately 25 trees were in each plot. My data consisted of the number of each organism or a mixture of organisms from each tree sampled, and I had 259 total organisms that I counted.”
Results: “The most common combination of organisms was moss and lichen, which were found on 56 trees out of 124 total. The fungi were not very prevalent in the area, but almost every tree sampled contained moss on its trunk…Moss made up the highest percentage, which was 46%, and lichen was the second most frequent, making up 36% of the total. The fungi were still not very prevalent in trees of that area, so it only made up 18%. That differed from my hypothesis.”
Research question: How does the location affect the amount of roots in the soil?
Hypothesis: Soil near streams will be enriched and have the most and thickest roots.
Process: “In order to do this experiment, I decided to dig six holes. Each were 16×10 cm deep at our two different campsites. At our first camp site on the stream, the top layer was mostly sand and silt. It had weak roots. It was very easy for me to dig through them and cut the roots… On the second stream location, it was the opposite…It contained some deeper, thicker roots but they were still easy for me to just break through. For the non-human activity, in the first campsite, its organic layer was pretty thin. After I started digging, you saw a lot of woodchips. They did have tree roots under there. They were pretty thick. For the second non-human activity campsite, there was also a large organic layer full of worms and decomposers. That had the thickest roots of all of them. For the human activity, the organic layer and the topsoil was full of the leaves and decomposers and mushrooms, but it wasn’t as thick as the non-human activity. At the second campsite with the human activity, there was a thin layer of almost pitch black soil and it was almost sparkly from mica crystals.”
Results: “After taking all my data, my conclusion was that the soil with the non-human activity had the strongest and the thickest roots because the soil was so rich and it was able to produce the most trees and have the most organisms and decomposers within it.”