Life Sciences Commons^™

Progression Of Activity And Predator Avoidance In California Grunion Larvae, Callyn E. Shelley

Seaver College Research And Scholarly Achievement Symposium

No abstract provided.

Carbon Black Exposure Induces Alterations In Mitochondrial Morphology In Human Lung Cells: A Software-Based Quantitative Analysis, Jennifer D. Duff, Brianna K. Laferney, Celina Y. Jones, Penn M. Mcclatchey, Jay Brewster

Seaver College Research And Scholarly Achievement Symposium

Nanoparticulates of pure carbon, carbon black (CB), are a common atmospheric pollutant in industrialized and heavily populated areas. They are produced primarily via combustion of fossil fuels, and represent a significant health hazard. They are known to worsen asthma and bronchitis when inhaled and to cause inflammation, heart dysfunction, and oxidative stress when incorporated into other organs. The key focal point of this work was to examine markers of stress signaling and cellular dysfunction when human bronchial epithelial cells (16HBE14o-) were exposed to CB particles ranging in size from 70 nm and averaging 130 nm in diameter. BrdU incorporation and …

The Effect Of Water Levels On Crayfish Aggression, Emory B. Johnson, Sarah E. Blase

Seaver College Research And Scholarly Achievement Symposium

Crayfish are a very prevalent invasive species that affect many different environments all over the world. Crayfish, specifically Procambarus clarkii, are an invasive species that have currently taken a foothold in the Santa Monica mountains and are threatening native stream species. There is currently a severe drought occurring in the Santa Monica mountains. The drought has been reshaping many aquatic environments by limiting space and resources such as food and shelter. Crayfish are a very aggressive species and adversely affect the habitat they inhabit by rapidly colonizing, burrowing, and their voracious diets. Due to the adverse effects crayfish can have …

Effect Of Drought On Resin Production In Woody Stems Of Rhus Ovata, Sydney T. Adams, Melody Young, Moriah Hall

Seaver College Research And Scholarly Achievement Symposium

Resin production in stems of woody plants is generated from resin canal secretions and is thought to play a significant role in protection from fungal infection and spread. This may be one of several factors associated with fungal infection and fungal induced dieback in plants during severe water stress or drought. We set out to determine if reduction in resin production in a chaparral shrub, Sugar Bush (Rhus ovata), was associated with severe drought in southern California. We hypothesized that dehydrated R. ovata would produce less resin than hydrated plants. Our null hypothesis was that there is no …

Genetic Effect Of Drought On The California Newt, Taricha Torosa, Madeleine M. Perrault, Samantha Fiallo, Alero Arueyingho, Cindy Kim, Laiken Ritchie

Seaver College Research And Scholarly Achievement Symposium

Droughts are now a common occurrence in Southern California and are known to cause population declines in many species, and such bottlenecks can cause a loss of genetic variation. Genetic variation was examined in a population of the California newt located in Arroyo Sequit Creek in the Santa Monica Mountains. Genetic data from animals examined prior to the current drought were compared to similar data collected from the population after it experienced several years of severe drought. We hypothesized that the drought impacted population should show less genetic variation in comparison to the pre-drought population. Nevertheless, there were no genetic …

Comparison Of Leaf Water Potential, Stomatal Conductance, And Chlorophyll Fluorescence Between An Invasive Weed, Schinus Molle, And A Native Chaparral Shrub, Ceanothus Spinosus, In The Santa Monica Mountains, Adam L. Fahey, Harry Zhou, Katie Callahan

Seaver College Research And Scholarly Achievement Symposium

The Peruvian peppertree, Schinus molle, is an invasive species in California that has escaped cultivation to competitively exclude native species in the landscape. One example of such competition is between a dominant member of the chaparral shrub community, greenbark ceanothus (Ceanothus spinosus), and S. molle. The mechanism of competitive displacement of chaparral by S. molle is not understood nor has it been previously studied. We hypothesized that during severe drought, such as occurred during the sumer/fall of 2016, S. molle would have a more favorable water balance then its native competitor C. spinosus, eventually leading to higher survival and species …

Hydraulic Mechanisms Of Fungal-Induced Dieback In A Keystone Chaparral Species During Unprecedented Drought In California, Natalie M. Aguirre, Marissa E. Ochoa, Helen I. Holmlund, Frank E. Ewers, Stephen D. Davis

Seaver College Research And Scholarly Achievement Symposium

Between 2012-2016, southern California experienced unprecedented drought that caused dieback in Malosma laurina, a keystone species of chaparral shrub communities. Dieback was especially severe in coastal exposures of the Santa Monica Mountains, leading to whole plant mortality exceeding 50% at some sites. We hypothesized that the endophytic fungus causing the dieback, Botryosphaeria dothidea, was successful in invading the xylem tissue of M. laurina because of protracted water stress, carbon starvation, or a combination of the two. We tested these possibilities in a controlled pot experiment by comparing three treatments, each inoculated with the fungus: (1) irrigated controls (2) …

Plant Water Relations During Drought-Induced Dieback In Greenbark Ceanothus, Ceanothus Spinosus, In The Santa Monica Mountains, Christopher F. Ross, Andrew Palaski

Seaver College Research And Scholarly Achievement Symposium

This experiment investigated Ceanothus spinosus dieback in the natural landscape of Pepperdine University’s campus in Malibu, California. We measured midday water potential, gas-exchange rates (photosynthesis and transpiration), chlorophyll fluorescence, and native embolism levels of stem xylem, comparing irrigated controls on campus to plants undergoing severe water stress in the natural landscape of our campus. The water potentials for naturally occurring C. spinosus (-6.6 MPa) was much lower than for irrigated controls (-3.4 MPa). Water stressed plants experience 47.2% embolism in their stem xylem that blocks water transport to leaves compared to 12.6% embolism in irrigated controls. This high embolism level …

A Comparison Of Water Potential, Photosynthetic Rate, Electron Transport Rate, And Stomatal Conductance Between Native Malosma Laurina And Exotic Schinus Molle, Karagan L. Smith, Agatha C. Heng, Viridiana Hernandez-Lopez

Seaver College Research And Scholarly Achievement Symposium

A Comparison of Water Potential, Photosynthetic Rate, Electron Transport Rate, and Stomatal Conductance between Native Malosma laurina and Exotic Schinus molle

Karagan L. Smith, Agatha C. Heng, and Viridiana Hernandez-Lopez

First-year Students as Scholars Program

Mentors: Natalie M. Aguirre, Kaitlyn E. Sauer, and Stephen D. Davis

Schinus molle is a relatively new invasive species in chaparral shrub communities of the Santa Monica Mountains, and has only recently been observed to displace native species of shrubs, such as Malosma laurina. To investigate the probably cause of S. molle’s invasiveness and mechanisms of competitive displacement of M. laurina, we compared …