Environmental Science
Alejandra Garcia, agarcia23@nevada.unr.edu
University of Nevada, Reno, with Dr. Mae Gustin & Dr. Heather Haines
Environmental Science
The effect of drought on records of atmospheric mercury: Analyzing tree rings through industrialization to present day
Human activities related to industrialization have increased atmospheric pollutants. One such pollutant is mercury (Hg), which has proven to have severe detrimental impacts on natural ecosystems. The exact amount by which atmospheric mercury concentrations have increased over time are poorly understood; therefore, this project aims to develop a high-resolution record of atmospheric mercury using tree rings since 1850. Here tree rings from Giant Sequoia trees located along the USA western coast serve as an annual archive of atmospheric mercury. Trees take up mercury from the air via the stomata, and mercury is transported to tree rings via the phloem, generating an annual record of atmospheric mercury concentrations through time. In addition, during drought stomata on the needles close and change the ratio of Carbon-13: Carbon-12 isotopes. By analyzing the carbon isotope ratios and mercury in annual sequoia tree rings, we can understand how drought has influenced tree atmospheric Hg uptake. These results will inform our understanding of how drought events affect mercury uptake within tree rings, and by extension the impact of climate on the historical record of mercury found in the rings. Additionally, these results will provide insight on how both natural and anthropogenic activities affect mercury in the environment allowing for better management of potential causes of damage to natural ecosystems.
Joaquin Lugo, joaquin_lugo1@baylor.edu
Baylor University, with Dr. Christie Sayes
Environmental Science
Degradation of Plastic Nurdles using Mechanical and Enzymatic Degradation
From our daily cups of coffee to cutlery and food packaging, plastics have become indispensable, especially in the food and drink industries. Many of our plastic products are formed from malleable plastic beads called nurdles. Nurdles are hard to keep packaged because of their small size. One major issue in plastic pollution is that the nurdles and the final plastic product do not degrade. This issue has encouraged researchers to research possible routes of degradation through physical, chemical, and biological mechanisms. Each process is different, but all methods ultimately break the bonds in the backbone of the plastic polymers into oligomers or minerals. For this study, mechanical grinding and enzymatic digestion were used separately and in combination to force plastic degradation. Materials were ground with a mechanical blender over varying times and temperatures. Further, the resultant degraded plastics were subjected to specific enzymes that bind to a specific plastic surface. Each plastic was analyzed for differences in surface features before, during, and after the degradation process using Fourier Transform Infrared spectroscopy and Scanning Electron Microscopy. Our preliminary results show that mechanical grinding increases the surface roughness of plastics and produces micronized flakes and particles that are easily removed from the larger plastic surface. In addition, the enzymatic degradation increases the oxidation of plastic surfaces which further helps to make the plastic brittle. These degradation processes have been shown to be effective in the literature, and this study will contribute to the knowledge of plastic degradation processes.
Cameron Crowder, ccrowder@stedwards.edu
St. Edward's University, with Dr. Amy Concillio
Environmental Science and Policy
Effects of Biochar-Compost Product Blends on Switchgrass Growth Rates
Biochar, compost, and compost tea have become increasingly popular methods for promoting plant growth for agriculture and restoration projects in recent decades. Because of their effectiveness and cheap production, they are commonly used for introducing nutrients, maintaining soil quality, sequestering carbon, improving the microbiome, disease resistance, drought tolerance, and preventing heavy metal absorption by plants. This research aims to understand the effects of combining biochar with compost products and distinguish which are best for switchgrass plant growth. Four treatments were used: biochar-compost (BC), biochar-compost tea (BT), biochar-compost-compost tea (BCT), and a control (Control). The tallest surviving plants were measured regularly to determine the plants’ height and width growth rates. The preliminary results indicated that the steepest rise in growth was in the biochar-compost treatment (BC), followed by the biochar-compost-compost tea (BCT) mixture alongside the control (Control), and then biochar-compost tea (BT). The results have shown that biochar-compost (BC) treatments do best for plant growth overall although more information needs to be gathered long-term before reaching a definitive conclusion.
Session Location
- Foster 123
Session Date/Time
- Thursday, 1:45 - 2:45pm
Session Type
- Oral Student Presentations
- Student Presentations