Life Sciences Commons^™

Reduced Ability Of Drought-Effected Plants To Assimilate Carbon Dioxide, Adrian Alvarado, Francisco De Mendiola, Julia Namkoong, Yunni Zhai

Featured Research

As a group, we hypothesized that plants affected by the drought will absorb less CO2 compared to those that are irrigated regularly by Pepperdine University. In order to test this out we used the Carbon Dioxide CO2 transmitter which analyzed the carbon dioxide levels and conduction of three leaves that are under the drought and three leaves that are fully irrigated. The results were outstanding. As we hypothesized, the irrigated leaves had significantly higher CO2 and photosynthesis values than the leaves that were in the drought. The results are clearly reflected in the data, and consistent with the initial hypothesis. …

Coreopsis Gigantea And Ice Plant Relationship On Point Dume, Lizzie Fichtner, Mccartney Ruff, Sean Hanson

Featured Research

This study looks to determine the affects of the non-native ice plant on the native Coreopsis gigantea located at Point Dume in Malibu, California. After examining the size of the Coreopsis we were able to identify that they were smaller in height when growing next to the ice plant and greater height when farther away. We concluded that the Coreopsis does survive next to the ice plant, however its growth is restricted. Through our research we discovered many factors that could attribute to the growth difference, yet further research is necessary to decipher the main one.

What You Can Do About The Negative Effects Of Methane, Jb Maza, Laurel Rodewald, Ashley Thurmond

Featured Research

Our central objective was to investigate the apparent rise in methane emissions and whether or not they are having a negative effect on the environment. By themselves, methane emissions are natural and self-regulating (and thus do not cause damage to the atmosphere), but our thesis is that a build up of methane emissions as a result of increased human activity/negligence poses a threat to the environment, and needs to be addressed in the quest to live sustainably. In our research, we chose to focus specifically on one source of methane emissions: permafrost, both because there is a significant amount of …

A Selected Surveyo F Ocean Acidifcation's Effect On Coccolithophore And Other Marine Ecosystems, Taylor Zaw, Joel Wood, Anthony Gonzalez

Featured Research

With it's rapid rate of generation, the coccolithophore was expected to adapt to the altered pH levels relatively quickly. By analyzing several scientific studies concerning this algae's interaction with various water qualities, the species' response is clarified. These findings are compared to rudimentary data concerning pH levels taken along the coast of Malibu.

Leaf Foliar Absorption In Pentagramma Triangularis And Polypodium Californicum, Justin Choe, Carlos Larios, William Prorok, Emily Rose Pierce

Featured Research

In Riparian and moist zones of the Santa Monica Mountains of Southern California, ferns flourish. However, the Mediterranean climate they live in is subject to drought, and the area is currently facing the worst drought it has ever seen. With little moisture in the ground and streams drying up, these ferns are running out of sources of water. However, being on the coast, the area is subject to fog nightly. This research was done to see if ferns can do leaf foliar absorption, getting their water source from the air rather than the ground. We hypothesized that ferns do leaf …

Comparison Of Photosynthetic Ability In Single And Double Palisade Parenchyma Leaves In Southern California, Vincent Quach, Ryan Sauer, Haley Smith, Christian Wright

Featured Research

Melaleuca quinquenervia is a myrtle (family Myrtaceae) with a propensity for invasiveness. The leaves feature an isobilateral orientation: vertically aligned with a layer of palisade parenchyma on both the adaxial and abaxial sides. Quercus agrifolia (Fagaceae) is a native evergreen with one layer of palisade parenchyma. Due to this structural difference, it was hypothesized that Melaleuca would have a higher rate of photosynthesis (Pn) and less reflectance (NDVI) of green light than Quercus. These two variables were compared using an unpaired t-test, yielding p-values of 0.1366 for NDVI and 0.04428 for photosynthetic rate. No significant difference was found between the …

Initial Post-Fire Resprout Success Of Q. Agrifolia, J. Californica, And P. Racemosa In Sycamore Canyon, Frida Morales, Sawyer Mcgale, Drew Bowers, Zahra Madraswala, Michael Mori

Featured Research

Resprouting after fire and during a drought can be one of the greatest challenges a plant faces. This phenomena was observed and recorded in three different species of trees: P. racemosa, Q. agrifolia, and J. californica, all located in the Sycamore Canyon study site in Pt. Mugu State Park. P. racemosa was hypothesized to initially be the most successful post fire resprouter. The rationale for this is that the DBH and deciduous factor would cause the tree's vascular system to survive and possess usable starches to power resprouting. The data was analyzed and found to support the hypothesis.

Drought-Induced Mortality In Malosma Iaurina And Ceanothus Megacarpus In Response To California's Changing Climate, Stefano Berrios, Stefani Francisco, Olivia Kim

Featured Research

The hypothesis of this research and experiment is that Malosma laurina is better adapted to drought than Ceanothus megacarpus due to its adaptation of deep roots. This addressed the question of which plants are better adapted to drought and by which adaptations are they superior. We decided to choose these two types of chaparral due to their differences in adaptations: Malosma laurina having deep roots and Ceanothus megacarpus utilizing cavitation resistance. Our method of investigation was to study the findings of scientific journal articles and to conduct our own experiment involving the mortality of Malosma laurina on the Pepperdine University …

Measuring Performance Of A Weedy Species (Nicotania Glauca) Vs. A Native Species (Venegasia Carpesioides) On The Pepperdine Campus, Emily J. Blair, Zach G. Coffman, Celina Y. Jones

Featured Research

This study investigated four different mechanisms of growth performance of a native chaparral species, Venegasia carpesioides, and a weedy species, Nicotiana glauca. The research group hypothesized that one or more of the following variables would be higher for the weedy species than the native species: photosynthetic rate, conductance, fluorescence, and electron transport rate (ETR). This hypothesis was formulated in order to provide a plausible explanation for why weedy species often outcompete native species when grown in proximity to each other, especially in a chaparral environment experiencing drought conditions. This hypothesis was tested by obtaining two groups of each species and …

Relationship Between Canopy Location And Tensile Strength Of Leave Of Heteromeles Arbutifolia In Malibu, Ca, Elena Witham, Melinda Marchiano, Danielle Reynolds

Featured Research

Our hypothesis is that canopy location has an effect on the characteristic tensile strength of leaves, with the leaves on the top of the canopy having greater strength than the leaves on the bottom. We tested our experiment by sampling leaves from the top and bottom of three H. arbutifolia specimens, obtaining raw measurements of size, and testing the tensile strength of each leaf using the Instron. We performed t-tests on the data to determine if the average length, width, thickness, and tensile strength were statistically different depending on if our p values were < 0.05 when top and bottom leaves of the same tree were compared. We chose a chapparral stand removed from heavy human traffic and influence, eliminating as many extraneous variables as possible by taking leaves from the same tree of the same age from the same position on the branch and chose three trial specimen of similar height in the same area to reduce the possibility of varying sunlight exposure or water supply from affecting leaf morphology in a way that canopy position would not. The results show that blade length between top and bottom is statistically significantly different, while blade thickness and lateral strength at midsection were not statistically different. From our analysis of the data, it is clear that leaves on the bottom of the plant were longer and broader than leaves on the top, but we determined that canopy location does not have a major effect on tensile strength or thickness, supporting a null hypothesis.

Community Structure And Differential Mortality Of Chaparral During Extreme Drought, Keb Doak, Allison Hubbard, Alawna Jamison

Featured Research

We have set out to find, in extreme drought, which species of chaparral are dominant and why they are dominating. We thought that the indicator species of chaparral, Adenostoma fasciculatum, would have highest relative density, relative frequency, and dominance in our research area. Additionally, plants with higher water potential values would have lower percentages of mortality. Chaparral with stronger ability to fluoresce (higher Fv/Fm value) would have lower mortality percentages due to their ability to dissipate excess energy, and therefore reduce water loss. By analyzing our vegetation area using point-quarter sampling system, we were able to record data that show …

The Effects Of Higher And Lower Co2 Levels In The Atmosphere On The Photosynthetic Rates And Stomatal Conductance Of Malosma Laurina In The Santa Monica Mountains, Victoria A. Thorsen, Maverick E. Turner, Colby P. Harriman

Featured Research

We hypothesize that higher CO2 levels will lead to a change in photosynthetic performance in the Malosma laurina population of the Santa Monica Mountains. We used one Malosma laurina that is across the street from university’s theme tower. We chose this specific plant because it was in the sun and it was in a well irrigated area. We selected a plant that is in non-shaded areas at 12:00 pm and then dark adapt them for 20 minutes. We selected an adult plant that was between four and six feet tall. We took the measurements from the upper leaves of the …

Relationship Between Canopy Location And Tensile Strength Of Leaves Of Heteromeles Arbutifolia In Malibu, Ca, Elena Witham, Melinda Marchiano, Danielle Reynolds

Featured Research

Our hypothesis is that canopy location has an effect on the characteristic tensile strength of leaves, with the leaves on the top of the canopy having greater strength than the leaves on the bottom. We tested our experiment by sampling leaves from the top and bottom of three H. arbutifolia specimens, obtaining raw measurements of size, and testing the tensile strength of each leaf using the Instron. We performed t-tests on the data to determine if the average length, width, thickness, and tensile strength were statistically different depending on if our p values were < 0.05 when top and bottom leaves of the same tree were compared. We chose a chapparral stand removed from heavy human traffic and influence, eliminating as many extraneous variables as possible by taking leaves from the same tree of the same age from the same position on the branch and chose three trial specimen of similar height in the same area to reduce the possibility of varying sunlight exposure or water supply from affecting leaf morphology in a way that canopy position would not. The results show that blade length between top and bottom is statistically significantly different, while blade thickness and lateral strength at midsection were not statistically different. From our analysis of the data, it is clear that leaves on the bottom of the plant were longer and broader than leaves on the top, but we determined that canopy location does not have a major effect on tensile strength or thickness, supporting a null hypothesis.

Elevation’S Effect On Malosma Laurinais Leaf Size, Callyn E. Shelley, Nathan R. Gehring

Featured Research

Our hypothesis was that the average leaf size of Malosma laurinais would be different at high and low elevations due to the variance in temperature and solar radiation. This is especially relevant considering the severe drought conditions of California. Testing the factors of growth for chaparral may help ecologists to better understand how the plants cope with abnormalities in the ecosystem. Our study examined variance in Malosma laurinais leaf length, width, area, curvature, and thickness at high elevation (610 meters to 629 meters) and low elevation (27 meters to 53 meters) located along Sycamore Canyon. Differences were only significant in …

Water Analysis Of The Malibu Lagoon And Pacific Ocean, Emily E. K. Kelly, Jillian S. Unruh, Maxwell K. Gamboa

Featured Research

This experiment tested the waters of the Malibu Lagoon and the Pacific ocean to compare levels of E.coli. We hypothesized that greater amount of E.coli would be present in the waters of the Malibu Lagoon. Because of the runoff and pollution existing in the lagoon, we predicted that higher levels of this bacteria would be found there. This study is significant because many organisms living in these waters can be negatively effected by large levels of E.coli. We used the most probable number method to determine the amounts of bacteria. A collection of samples from three testing sites in both …

Nutrient Return To Soil In The Santa Monica Mountains After Combustion, Taylor Brooke Shapiro, Antonia Freund, Megan Chou

Featured Research

In this study, levels of phosphorus, nitrogen, and PH from eight uniform soil samples from the Santa Monica Mountain swere assessed. Our first testing group contained four uniform samples of soil, which were tested under regular drought conditions. Our second testing group contained four identical samples, which we tested under regular drought conditions and also exposed to fire. Our hypothesis was that soil after wildfire will have different amounts of phosphorous, nitrogen, and Ph. Our research found that average phosphorus uptake in unburned samples vs. burned samples were significantly different at a P<0.0001. Nitrogen and pH levels however, were not found significantly different between burned and unburned samples.

Post-Fire Recovery Of Juglans Californica In Sycamore Canyon: Gas Exchange Performance Of Unburned Mature And Burned Epicormic And Basal Resprouts, Taylor Stucky, Gabby Gurule-Small

Featured Research

Sycamore Canyon experienced a fire during April of 2013. This allowed for the comparison of burned and unburned individuals in the area. Based on its resprouting types and abundance in the area, Juglans californica made for a good test species. A total of eighteen individuals were tagged and used with a LiCor6400-XT to find fluorescence, Jmax, Vcmax, TPU, gm, photosynthesis, and conductance. Leaf samples were sent to California State University, Bakersfield for Nitrogen analysis to obtain PPNUE and percent nitrogen (with specific leaf area). These data were compared between unburned mature, and burned basal and epicormic resprouts. ANOVA testing established …

Ethnobotanical Promotion Of Fibroblast Growth Using Yerba Santa Extract, Carlie F. Dobbins, Paige A. Sutherland, Emily A. Woods

Featured Research

Ethnobotany is a promising way of discovering new drugs, drawing on the knowledge of generations of traditional healers. The healing qualities of Yerba Santa (Eriodictyon crassifolium) have been recognized for hundreds of years by Chumash Indians and Spanish missionaries, so much so that they came to call it “holy herb”. We decided to determine the efficacy of Yerba Santa by extracting potentially bioactive molecules in methanol and then using this extract to treat scales from goldfish (Carassius auratus) to test the hypothesis that the Yerba Santa extract would alter the growth of fibroblasts. Compared to scales treated with only modified …

The Mechanical Strength Of Malosma Laurina Leaves Corresponds With Survivability During Extreme Drought, Alexander Booth, Alexander Corwin, Matthew Chung

Featured Research

With the recent extreme drought that Southern California is facing, many plants’ survivability adaptations have proven insufficient. The Malosma laurina plant is known for it’s incredible ability to survive through droughts and wildfires with it’s adaptations of resprouts regeneration and it’s roots that can reach a depth of 40 feet to gather deep ground waters. We theorized that the mechanical strength of the leaves directly relates to its survivability during droughts. To explore this theory we took focused our theory specifically on M. laurina resprouts. With two groups, one fully alive and one dying, we took six samples from six …

Effect Of Shear Stress Direction On Endothelial Function And Enos Phosphorylation In Soleus Feed Arteries, Blanca B. Perez, Jay Brewster, Jeffrey Jasperse

Featured Research

Blood flow feeding tissues and organs is closely regulated in order to meet metabolic and functional needs. Control of blood flow is accomplished by regulating the diameter of the arteries and arterioles feeding different organs. Several neural, hormonal, chemical and mechanical mechanisms contribute to the constriction and dilation of arteries. Shear stress, the frictional force created by streaming blood on the endothelial layer of arteries, is one of these mechanical mechanisms (1). Shear stress causes both acute and long term effects on endothelial cells (1,2,5).

Blood in arteries typically flows away from the heart towards organs (causing antegrade shear stress) …

Leaf Mechanical Strength Corresponds To Tissue Water Relations In Twelve Species Of California Ferns, Breahna M. Gillespie, Stephen D. Davis, Jarmila Pitterman

Featured Research

The dominant vegetation types in southern California’s coastal foothills are chaparral and costal sage scrub. Chaparral shrubs have mechanically strong evergreen leaves whereas coastal sage scrubs bear mechanical weak, facultative deciduous leaves. What about the ferns that live in the understory of these vegetation types, especially considering their adaptations to a summer dry, Mediterranean-type climate? We tested the hypothesis that some fern leaves are stronger than others and mechanically strong leaves are associated with greater dehydration tolerance. Twelve fern species were examined. Tissue water relations were assessed via pressure volume curves using Scholander-Hammel pressure chambers. We estimated osmotic potential at …

Relationship Between Dehydration Tolerance Of California Ferns And The Mechanical Strength Of Their Stipes, Helen I. Holmlund, Jarmila Pitterman, Stephen D. Davis

Featured Research

In vascular plants, water moves upwards through xylem vessels/tracheids due to negative pressures created by the evaporative pull of water. Under severe dehydrated, extreme negative pressures are known to cause xylem cavitation and embolism. In seed-bearing plants, the mechanical support of stem xylem has been shown to be a good predictor of cavitation resistance, presumably because sclerenchyma fibers buttress against micro-fracture or collapse of conduit walls. In spore-bearing plants, such as ferns, current anatomical theory indicates that mechanical support lies external to underlying xylem, in the outer hypodermal region, leaving the central xylem in ferns without any fiber support. In …

Vegfr-2 And Vegfr-3 Expression As A Function Of Jagged-1 Over-Expression In Huvec Cells, Caleb Stubbs

Featured Research

Angiogenesis is the sprouting of new blood vessels from pre-existing vessels initiated from vascular endothelial cells in response to exogenous chemical signals. Principle signals are vascular endothelial growth factors (VEGF) that direct cell growth and differentiation by binding to endothelial cell surface VEGF receptors (VEGFR). In Human Umbilical Vascular Endothelial Cells (HUVEC) initial sprouting cells or “tip cells” send signals to neighboring cells “stalk cells” responsible for sprout elongation. Multiple VEGF signals and receptors are known, but the main angiogenic signals are from VEGF-A through VEGFR-2 and VEGFR-3. Regulation of VEGF receptor expression can be influenced by the Notch signaling …

The Effects Of Carbon Black On Cell Viability, Abigail Calixto, Jay Brewster

Featured Research

Carbon black (CB) is a type of nanoparticle that is found in air pollution and is a known environmental toxin. The purpose of this work is to evaluate whether CB exposure activates cell death via apoptosis in cultured cell lines, supporting future work focused upon assessing the signaling pathways that might be induced by this exposure. Using adenocarcinomic human alveolar basal epithelial (A549) and baby hamster kidney (BHK-21) cells, we hypothesized that carbon black exposure causes cell death and potentially stress signaling via the endoplasmic reticulum (ER). The cells were exposed to CB and data collected for varied doses and …

Effects Of Uv-Radiation On Feeding Behavior In Dendrobates Tinctorius, Taylor S. Stucky, Arthur Garnica

Featured Research

UV-B levels have recently been increasing with the depletion of the ozone layer. Recent data have shown that amphibians are especially susceptible to UV-B, with poison dart frogs being one focus in these studies. The purpose of this study was to determine if UV-B radiation affects the foraging behavior of poison dart frogs. This study was conducted with a captive population of juvenile Dendrobates tinctorius at Pepperdine University in Malibu, California. Frogs underwent one of three treatments: UV only, Food only, and UV and Food. UV only trials were conducted using two UV lights emitting approximately 1.2 uW/cm2 of UV …

Enzymatic Activity In The Chorion For Hatching In The California Grunion, Emily R. Pierce, Vince V. Quach, Karen L. Martin

Featured Research

Leuresthes tenuis is a small, silverside fish that spawns on the beaches during some of the highest tides of the summer months. Of the many unique traits to the species including that the eggs develop fully out of water to the point of hatching competence but will not hatch until presented with an environmental cue, which causes them to hatch in less than a minute. The purpose of this study is to better understand the role of enzymes called chorionases, which act to break down the chorion (egg membrane). I hypothesize that the chorion begins to weaken in this species …

Assessment Of P38 And Extracellular Signal-Regulated Kinase (Erk) In Regulating Apoptosis During Low And High Er Stress, Zachary G. Coffman

Featured Research

The endoplasmic reticulum (ER) is an important organelle within the cell that has many functions including protein folding. When the protein folding capabilities of the ER are compromised ER stress occurs. Extracellular signal-regulated kinases (ERKs) and p38 are MAP kinases that are induced as a result of ER stress. ERK is a protein that has been associated with cell proliferation and survival while p38 is a protein that has been associated with apoptosis, which is programmed cell death. The objective of this study was to measure ERK and p38 induction over time during low and high ER stress. Another objective …

Ethnobotanical Promotion Of Fibroblast Growth Using Yerba Santa Extract, Carletta F. Dobbins, Paige A. Sutherland, Emily A. Woods

Featured Research

Ethnobotany is a promising method for discovering new drugs, drawing on the knowledge of generations of traditional healers. For hundreds of years, the Chumash people have lived in the coastal regions of California, becoming experts on the many uses of its natural resources. One such resource is the Yerba Santa plant (Eriodictyon crassifolium), which was used by the Chumash to treat a myriad of conditions including coughs, chest pain, and fever. It was also used as a poultice on wounds and cuts, suggesting that the plant has a stimulating effect on the growth of skin cells. Because of these qualities, …

Planetary Heat Sink Uncouples Temperature Increase From Rising Co2: Climate Change Hiatus Explained, Monica Houweling, Megan Gavitt, Jean Kim

Featured Research

The current hiatus in terms of global climate change has been linked to a greater phenomenon of a change in climate than seen in previous historical trends. The globe was rising in temperature throughout the beginning of the 21st century, but has entered into a hiatus, a period where the CO2 levels continue to rise but the global temperature is remaining constant. It is predicted that temperatures will continue to rise once this hiatus passes. The main cause of this hiatus, known as planetary heat sink, is the concept that the ocean is absorbing more heat to offset the increasing …

Effects Of Personal Gardens On The Reduction Of Atmospheric Co2 And Climate Change, Jacqueline N. Brody, Paige L. Elson, Brittany V. New

Featured Research

This study aims to explore the long-term benefits of home gardening if every student at Pepperdine were to hypothetically sustain their own home garden in the state of California and the effect that this would have on state carbon absorption as a means of decreasing atmospheric CO2 and reducing further climate change.