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«Strengthening the Nation through Diversity, Innovation & Leadership in STEM San Antonio,Texas · October 3-6, 2013 Get Connected! Connect with the ...»

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1 Triclosan, an antimicrobial that is used in a variety of products such as plastics and toothpastes, can be found in freshwater streams used for irrigation water. In this study, the objective was to determine the potential effects of Triclosan on tomato plant growth, Triclosan accumulation in plant tissues, and heterotrophic bacterial counts. In a greenhouse study, 12 tomato plants were grown for 14 weeks and irrigated weekly with the following concentrations of Triclosan: 0.00, 0.015, 0.15, and 1.5 µg/l. Harvested plants were sectioned into roots, shoots, leaves, and fruits before drying to obtain biomass and then pulverized prior to a solid phase extraction using a 1:1 methanol-to-acetone solution. Extractants were concentrated prior to GC-MS analysis. Both rhizosphere and bulk soil bacteria were enumerated by serial dilution plating on R2A. Total plant biomass showed a decreasing trend with increasing Triclosan concentrations, but was not significant (p 0.05). Initial extractions indicate an increase in Triclosan concentrations with treatment concentrations. Rhizosphere bacterial counts were not significantly different (p = 0.4552) between treatments with an overall mean of 3.8 x 108 CFU/g dry soil. However, bulk soil heterotrophic bacterial counts were significantly higher (p = 0.0002) in the higher Triclosan treatments (0.15 and 1.5 µg/l) with 3.7 x 107 and 4.1 x 107 CFU/g dry soil, respectively. These data indicate that Triclosan may potentially decrease plant growth while increasing Triclosan contamination of a crop plant. Additionally, Triclosan may be selecting for resistant soil bacteria while not affecting rhizobacteria due to a plant-microbe interaction.



Aracely Tellez, Mariana Vargas, Vanessa L. Lougheed.

University of Texas at El Paso, El Paso, TX.

With warming in the Arctic, more nutrients are being released from thawing permafrost into Arctic aquatic ecosystems.

The impact of these changes on aquatic food webs is largely unknown. Zooplankton are abundant in Arctic tundra ponds; recent studies have indicated changes in these communities as ponds warm and become more nutrient rich. This study was done to examine the effects of nutrient enrichment and warming on algal community structure and consequently on Daphnia pulex reproduction. Daphnia pulex, an organism commonly found in the Arctic and generally used to determine the quality of water for living organisms, was grown at 2 different temperatures (21 and 25 °C) in arctic algae cultures. Reproduction, mortality, and growth rates of Daphnia, as well as gross taxonomic algal composition were measured. We hypothesized that nutrient enrichment and warming would produce a cascading effect on aquatic organisms. Preliminary results show distinct differences among treatments. Daphnia kept at 21 °C, did not increase in numbers although algae abundances increased substantially. Warmer cultures, however, had inconsistent numbers throughout the experiment. Populations of Daphnia tripled within days then suddenly dropped the numbers to zero while algae also declined in numbers. Preliminary results from nutrient enrichment indicated phosphorus as a limiting factor for algal growth, having a direct impact on D. pulex growth and reproduction.

These results support field observations where increased nutrient levels and algal biomass in Arctic tundra ponds lead to changes at higher trophic levels. Future studies will look at both warming and nutrient effects in a factorial experimental design.



Deidre Pine, Stephen Hanson.


Phytophthora capsici and Verticillium dahlia are some of the leading causes of loss in chili pepper production in the Southwest. Phytophthora capsici is part of the genus Oomycetes (water mold) and which causes huge economic loss on crops worldwide, along with Verticillium dahlia. The absence of natural resistance to these pathogens as well as

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Lisa McBride1, Andrew Heyes2, Christopher Rowe2, Russell Burke3, Cheryl Clark2.

New Mexico Highlands University, Las Vegas, NM, 2Chesapeake Biological Laboratory, University of Maryland Center 1 for Environmental Sciences, Solomons, MD, 3Hofstra University, Hempstead, NY.

Synthetic musk fragrances are found in almost all scented personal care products. They have been measured in water, air, sewage sludge, and various biota from all over the world. However, no studies have measured synthetic musks accumulated by parents and transferred to offspring. Because coastal cities release treated and sometimes untreated sewage effluent “to tide,” research on the impact of personal care products on resident and especially longlived organisms which may accumulate the compounds over long periods of exposure is needed. We selected the diamondback terrapin because it is long lived and inhabits the entire eastern seaboard of the United States across a wide salinity gradient. In this preliminary study, we have targeted 1 nitro musk (musk xylene, [MX]) and 1 polycyclic musk (galaxolide [HHCB]), and are assessing their presence in the eggs of northern diamondback terrapins inhabiting a contaminated site (Jamaica Bay, New York) compared to a less-impacted site in the Patuxent River, Maryland. We have developed a method using gas chromatography-mass spectrometry for analysis of these parent compounds in terrapin eggs. This field based study will be the first step in assessing the degree of exposure of terrapin embryos to synthetic musks accumulated by the parents.



Keefah Khalil, Christine Case.

Skyline College, San Bruno, CA.

Cape ivy (Delairea odorata) was introduced from South Africa to the United States in the 1850s and is now the primary threat to biodiversity along the central California coast. Although the decrease in plant diversity following cape ivy infestation has been documented, there is no published research on the effect of cape ivy on soil productivity.

Soil microbes provide essential ecosystem services such as nutrient mineralization. Therefore, the purpose of our study is to determine whether cape ivy disrupts soil microbial ecology. We hypothesize that cape ivy is disrupting microbial populations, which disables native species or gives cape ivy a selective advantage. We are comparing soil microbial activity of cape ivy infested areas with the native coastal scrub community. Soil samples were collected from depths of 0 to 30.5 cm. Community-level physiological profiling employing Biolog Ecoplates was used to compare catabolic activity in the microbial community in cape ivy infested areas with that of the native coastal scrub community. Our preliminary results show that cape ivy does affect the function of soil microbial communities. At 12 cm, catabolic capabilities of the cape ivy associated microbial communities are 7% greater than those of the coastalscrub associated community. Functional diversity in cape ivy soil is 91.4%±7.0 compared to 82.8%±2.1 in the coastalscrub soil at 12 cm. We are examining activities of nitrifying and denitrifying bacteria in the different soil samples. Our results and analysis of functional traits will contribute to understanding the mechanisms by which cape ivy maintains dominance and may help achieve long-term restoration goals.





Stephen Morris, Erin Lehmer.

Fort Lewis College, Durango, CO.

Increased global temperatures are predicted to have significant impacts on a number of plant and animal species and these impacts are expected to be most profound for species living in extreme environments. Yellow-bellied marmots (Marmota flaviventris) are hibernating mammals that live at high elevations in Colorado and depend heavily on cold winter temperatures to complete their annual life history events. Our research is focused on evaluating how increased winter temperatures will impact foraging behavior, physiological health, and allostatic loads of marmots living at both high (10,800 ft) and low (7,500 ft) elevations within their geographic ranges. As part of this research, we are sampling marmots in early and late summer to determine their body masses, growth rates, and physical health.

We will also collect blood samples to run an assortment of lab-based analyses intended to determine allostatic load, including estimates of C-reactive protein, glucocortocoid levels, and innate immunity. We will conduct extensive soil and vegetation inventories to determine soil moisture and pH, vegetation biomass and nutrient content, and the timing of plant phenology. This information will be used to determine the extent to which habitat quality differs between marmots at high and low elevation. Finally, we are using temperature-sensitive data loggers to indirectly monitor foraging time, as marmots living in low-quality habitats would presumably spend more time per day foraging compared to their counterparts living in high-quality habitats. Results of this research will provide important information about how climate change impacts plant and animal community dynamics.




Suzanne Apodaca, Wen-Yee Lee.

University of Texas at El Paso, El Paso, TX.

Bisphenol A (BPA) is a man-made environmental contaminant of emerging concern possessing controversial endocrine disruption properties. An increased interest has been seen in its accurate determination in various media order to estimate the exposure to BPA and the associated health risk. The goal of this study was to develop an environmentally friendly (green), sensitive, and efficient method to analyze bisphenol A (BPA) in liquid milk samples.

The technique uses stir bar soprtive extraction (SBSE) and thermal desorption accompanied with gas chromatography and mass spectrometry (GC/MS). For SBSE sample preparation, sodium carbonate served as a pH adjustment agent, acetic acid anhydride as a derivatization agent, mirex as the internal standard, and a preconditioned stir bar were added to a 20 mL volume of sample. After 2 hours of stirring, the stir bar was desorbed in a thermal desorption unit and BPA was analyzed by GC/MS. BPA-spiked, whole-fat milk was used as the model sample matrix. BPA with a concentration range from 0.01 to 10 ug/L (ppb) was added to the milk sample to study the linearity and limit of detection. Different solvent systems (such as methanol) and additive effects were investigated with the SBSE process to determine BPA recovery in milk samples.



Kathryn Rico, James Montgomery.

DePaul University, Chicago, IL.

Prairie Wolf Slough (PWS) is a restored, farmed wetland in northeastern Illinois that was created to improve the water quality of stormwater runoff entering the North Branch of the Chicago River. Past research has shown that concentrations of soluble reactive and total phosphorous in water that discharges from PWS are higher than the phosphorus concentrations in water entering the wetland. It is important to delineate the various sources of phosphorous in PWS in order to develop a comprehensive phosphorous budget. This project assessed the contribution of phosphorous from sediment/soil being deposited in the marsh. Sediment/soil samples were collected and measured for Mehlich-3 soil test phosphorous, carbon-nitrogen ratio, and particle size. Sediment traps placed in the marsh measured monthly sedimentation rate. Incremental soil samples were taken at 15-cm increments to a total depth of 90 cm from a subset of points along a transect through the center of the wetland; these were analyzed for nitrates, free iron oxides, and soil test phosphorous. Correlation analysis shows weak associations between soil

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Cindy Barrientos, Teresa Palos.

El Camino College, Torrance, CA.

Pharmaceuticals provide relief from disease signs and symptoms. However, substances that are meant to help people could also be harming the environment. The US Geological Survey has sampled water from 139 streams and found traces of nonprescription drugs in concentrations as high as 17.4 micrograms per liter. It is important to understand the impact of nonprescription drug presence in water-based habitats. This is especially true considering rising pharmaceutical consumption. According to the Consumer Healthcare Products Association, over-the-counter drug retail sales increased to $17.4 billion in 2011. This study investigated the use of Vibrio harveyi, a marine bacterium, as a biological indicator for the impact of over-the-counter drugs. V. harveyi relies on quorum sensing, a form of cell-tocell communication, that uses chemical autoinducers to transmit signals to entire bacterial populations for the control of behavior. A high concentration of the autoinducer triggers bacterial bioluminescence. Bioluminescence generation and changes in bacterial culture brightness were evaluated when exposed to nonsteroidal anti-inflammatory drugs (NSAIDs). The results suggest that ibuprofen had the most detrimental effect, but only when the bacteria were exposed prior to the generation of bioluminescence and not after it had been produced. Both ibuprofen and naproxen had toxic effects at concentrations as little as.054 mg/ml. Aspirin had no effect on bioluminescence or bacterial growth. Additional work should be performed to further study NSAID environmental impact and programs developed to decrease their presence.

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