SESSION A (9:00-10:30AM)
Location: Sorenson (2nd floor), Alumni House

Microtubule rigidity and associated stability phenomena
Tanner Hoole, University of Utah

Faculty Mentor Michael Vershinin, University of Utah

SESSION A 9:00-9:15AM
Sorenson, (2nd floor), Alumni House

Microtubules (MTs) are polymers of alpha-beta tubulin dimers and are the most rigid part of the cytoskeleton in eukaryotic cells. Extreme cold and heat are known to cause MT depolymerization. Several published reports showed that MTs stabilized with slow- or non-hydrolyzable GTP analogs or aldehyde-type cross-linking declined with increasing temperature in a small range of temperatures (20-35°C). Taxol-stabilized microtubule rigidity was reportedly temperature-independent. Our lab expanded on this by (1) expanding the temperature range from 0°C to as high as 50°C and (2) by testing single MTs polymerized using three different nucleotides: GTP with Taxol, GMPPCP with Taxol, and GMPCPP. Both GMPPCP and GMPCPP are non-hydrolyzable analogs of GTP, and GMPCPP is an established promoter of MT nucleation and growth which enables MT stabilization without Taxol. We observed systematic differences between persistence lengths in these three backgrounds but only statistically insignificant variation with temperature for each background. Specifically, we find that MT persistence length is log-normally distributed which not only obscures temperature variability of rigidity in our assays but also likely makes any such variability insignificant for cell function.

Controlling Harmful Algal Blooms Through Biomanipulation at Utah Lake
Cristina Chirvasa, Utah State University

Faculty Mentor Timothy Walsworth, Utah State University

SESSION A 9:20-9:35AM
Sorenson, (2nd floor), Alumni House

The alteration of food web dynamics through addition or removal of species can have major impacts on the size-structure and abundance of other species. Changes in the size-structure and abundance of zooplankton, whose rapid life-histories allow for swift responses to food web changes, can readily impact prey quality and availability for fishes. Utah Lake has been the site of intensive common carp (Cyprinus carpio) removal efforts since 2009, experiencing a biomass reduction of over 75% at one point. Our previous research has linked reduction in carp biomass to changes in zooplankton species composition, but the impact on size-structure of individual taxa had not been examined. Here, we analyzed the body length of five common taxa, Calanoid and Cyclopoid copepods, Daphnia, Diaphanosoma, and Ceriodaphnia, from 2013-2020 using zooplankton monitoring data to examine their response to carp removal in Utah Lake. We found that all five taxa increased in size during periods of low carp biomass. Additionally, all taxa except Daphnia demonstrated a negative trend across years, suggesting other factors (e.g. lake level, temperature) are influencing zooplankton body size. Increased size during periods of lower carp biomass suggests a release from predation pressure by carp. Since zooplankton size can have important positive effects across different trophic levels, other zooplanktivorous fishes in Utah Lake, including the endemic June sucker (Chasmistes liorus), will benefit from the increased availability of energy-dense, larger zooplankton. Further, larger zooplankton are generally more efficient grazers of phytoplankton and thus may help limit the severity of harmful algal blooms. Future analyses will examine the relationship between zooplankton size and algal bloom severity in Utah Lake.

LiDAR Analysis of a Potential Rockfall Source Area
Kieren Condie, Utah Tech University

Faculty Mentor Alex Tye, Utah Tech University

SESSION A 9:40-9:55AM
Sorenson, (2nd floor), Alumni House

Rockfall is an important mechanism of erosion in high-relief regions. Rockfall events pose significant risk to human life and infrastructure in such areas. Although many factors have been proposed to influence rockfall, including frost weathering, daily and seasonal temperature changes, mechanisms that trigger rockfall remain enigmatic. Better understanding rockfall triggering can aid with hazard mitigation. We report new monitoring data from a potential rockfall source area in Zion National Park, where previous rockfall events have damaged roads, trails, and buildings and harmed visitors. In the Park, a precariously balanced pillar of resistant Springdale Sandstone, entirely separated from an adjacent cliff by a joint, is located upslope of several historic buildings. We used terrestrial LiDAR to construct a 3D-model of the pillar in the form of point cloud data. The 3D-model allows for analysis of the geometry of the pillar, calculation of the center of mass, and exploration of scenarios for failure of the pillar due to displacement of the center of mass. Our new analysis, together with displacement meters that have been placed for continuous monitoring of rock pillar movement, provide the basis for higher-resolution prediction of rockfall failure mode. Our approach may be exportable to other sites that are a high priority for rockfall mitigation.

Assessing the effectiveness of cattle exclosures on spring ecosystems in Escalante
Lauryn Crabtree, Brigham Young University

Faculty Mentor Richard Gill, Brigham Young University

SESSION A 10:00-10:15AM
Sorenson, (2nd floor), Alumni House

Springs are endangered ecosystems providing water and life to over 80% of plants and wildlife on the Colorado Plateau. The Bureau of Land Management and U.S. Forest Service implement the use of fencing called exclosures to exclude livestock from spring sites on the Grand Staircase-Escalante National Monument in effort to restore these ecosystems from years of grazing and damage. The purpose of this study is to determine if livestock exclosures are effective in protecting and restoring previously grazed spring ecosystems. In the summer of 2021, 56 springs contained within the Escalante Watershed in the GSENM were surveyed to document and observe livestock impacts on exclosed and unexclosed springs. I analyzed these data by comparing the erosion, nonnative plant abundance, and percentage of grazing of sites with exclosures to springs without exclosures, and in areas where livestock cannot graze. My results show that exclosed springs were able to have low levels of erosion, but that nonnative plant populations and grazing percentages were comparable to areas still actively being disturbed by cattle. These results suggest that additional management strategies need to be implemented in order to restore damaged springs back to their natural, undisturbed status.