Decomposition in soil is a major component of the carbon cycle. The breakdown of organic matter releases carbon emissions, which are ultimately released into the atmosphere. Extracellular enzymes are considered to be largely responsible for the decomposition of organic matter; however, little research has been conducted on the functional lifespan of these enzymes. In this study, we measured the persistence of enzyme function in soil with varied water holding capacities (15%; 35%; 55%). Soil was collected from a chaparral terrestrial ecosystem. Soils were kept under constant chloroform fumigation to prevent additional production of enzymes from microorganisms.  Six hydrolytic enzymes were selected (α 1,4-Glucosidase, β-1,4-Glucosidase, β-D-1,4-Cellobiosidase, β-1,4-Xylosidase, β-1,4-N-acetyl-glucosaminidase, and Acid Phosphatase) and measured for potential function activities biweekly over a course of 12 weeks. Decay rate constants were calculated and fitted to first-order and zero-order models. Generally, the greater the water holding capacity, the longer persistence of activity was observed.  Alpha-glucosidase had less persistence than the other enzymes with beta-glucosidase activities persisting the longest.  This information can be utilized to better understand the constraints on enzyme stability in soil

Poster Presentation

Session 2

1:00pm – 2:15pm
Grand Salon

Biology

Earth consists of approximately 70% ocean, and due to this, about 90% of the world’s freight transportation occurs there. In the U.S. alone, there has been $2.7 billion worth of corrosion damage to ships. If we include all direct corrosion costs in the U.S., that number skyrockets to $276 billion dollars worth of damage. Continuing the research on the qualitative data we achieved from previous COAST research, which shows the properties of B. subtilis biofilm inhibiting the corrosion process of steel chips and the opposite being true of P. lipolytica and  P. fluorescens, we plan on getting more quantitative data. We will select a variety of steel or aluminum alloys commonly used near or in ocean water and allow a biofilm to grow on each one. For each metal and biofilm combination, we will have a blank control, one submerged in sterilized ocean water and one in unsterilized ocean water. Using techniques such as the scanning vibrating electrode (SVET), we plan to get quantitative data on corrosion indication by mapping out an electric potential field after electrochemically corroding it. Multiples of the same sample will undergo other testing, such as getting topological images of the material using scanning electron microscopy (SEM) and fluorescence to quantify cell amounts. This process will be repeated for each one after 1, 3, and 10 days of growing the biofilm.

Poster Presentation

Session 2

1:00pm – 2:15pm
Grand Salon

Biology

Distinct patterns of body size and shape across elevation have been observed in many species, leading to different ecogeographical hypotheses or ‘rules’. According to Bergmann’s rule, organisms living in cooler climates (e.g., high latitude, high elevation) tend to have larger body size than those living in warmer climates. According to Allen’s rule, organisms living in cooler climates tend to have shorter appendages (e.g., shorter limbs, shorter beaks) than those living in warmer climates. However, few studies have tested these hypotheses in amphibians and the observed patterns vary across taxonomic groups. We examined Bergmann’s and Allen’s rules on a diverse group of terrestrial-breeding frogs (Strabomantidae) to understand how species’ body size and body shape vary across elevations. We tested whether (1) species living at high elevations tend to have larger body size than those living at low elevation, and whether (2) the relative size of the appendages (e.g., limb length, head length) in species living at high elevations tend to be shorter than those living a low elevation. We compiled a dataset for ~300 species representing six genera, and used elevation as a proxy for temperature, to assess the relationship between morphological traits and elevational midpoint. Most papers reviewed contained data on one or more species, and we recorded the museum number, coordinates, elevation, and measurements of individual specimens. Bergmann’s rule was supported in one of the six examined genera (Phrynopus) and Allen’s rule was supported in three of the six examined genera (Bryophryne, Phrynopus, Pristimantis). We discuss these findings with respect to microhabitat use and thermal ecology.

Poster Presentation

Session 2

1:00pm – 2:15pm
Grand Salon

Biology

In 2015, Dr. Dilly and his students established two intertidal long term monitoring sites on Santa Rosa Island. The sites are located at Skunk Point and Bechers Bay. They were chosen based on their proximity to the Island Research Station and the absence of other rocky intertidal monitoring sites on the northeastern side of the island. Vertical transects are a useful tool for evaluating changes in species diversity for entire sites. Point intercept is used to track species coverage in a small area. We have four zones at each site: low, mid, high, and splash zone, with four point intercept plots per zone. Using these monitoring tools, we analyzed the percent coverage, average distance from baseline, and count data of select species to identify community and diversity changes. While we have observed no significant change in overall diversity at either site, there have been significant changes in select species abundance. In Bechers Bay, the percent coverage of Endocladia muricata and Anthopleura sp. have increased, while Phragmatopoma californica has decreased. Skunk Point also showed increased percent coverage of Anthopleura sp., while Mussels and the rockweed Silvetia compressa remained stable at both sites. The ecological relevance and limits of these findings are discussed in this poster.

Poster Presentation

Session 1

9:15am – 10:30am
Grand Salon

Biology

Crustacean based fertilizers are far from abnormal considering how they are so rich in chitin which break down into important nutrients such as calcium and nitrogen. Crab and shrimp are most common fertilizers however non-native crayfish are hard to avoid in the streams of the Santa Monica Mountains. Since these crayfish are non-native, efforts to remove these crustaceans to restore the river and habitats have been effect but with this crayfish waste, the question is raised: Could crayfish exoskeletons be used as fertilizer to benefit plants and enrich soil? To determine if crayfish exoskeletons can be used as fertilizer for plants, we performed a garden experiment where leafy vegetables were planted into soil that was fertilized with either crab, shrimp or crayfish, and allowed to grow over weeks.  Soil samples taken before and after planting, dried in an oven and the tested for nitrogen, phosphorus and potassium, while the vegetables were analyzed based on growth factors such as weight and height following.  All of these factors are then compared to the control but also to each other, to determine if crayfish is a suitable alternative fertilizer.

Poster Presentation

Session 1

9:15am – 10:30am
Grand Salon

Biology

Holometabolous insects are the most successful of the insects worldwide.  They are characterized by complete metamorphosis between juvenile and adult stages.  The larva of a holometabolous insect occupies a different niche as an adult of its species, allowing for less competition between parents and offspring.  We decided to study the prevalence of holometabolous insects on campus at California State University Channel Island using insects collected by entomology students (BIOL 452) in 2019, 2021, and 2023.  We calculated the proportion of holometabolous insects overall and compared the abundance of the four largest holometabolous orders (Hymenoptera, Diptera, Lepidoptera, and Coleoptera) both overall and by year.  We used a chi-square test to analyze the data for significance.  Holometabolous insects were consistently more numerous than non-holometabolous insects.  There was no significant difference between the overall number of each of the major holometabolous orders.  However, there was a statistically significant change in population number within the orders year-to-year.  The cause of this trend cannot be determined, but this could be investigated in further research.  Monitoring changes in insect activity and populations is important, especially as global warming continues to change the environments in which they live.

Poster Presentation

Session 1

9:15am – 10:30am
Grand Salon

Biology

Narrow-leaved milkweed (Asclepias fascicularis) is an ecologically important native plant that provides habitat and food for Monarch butterflies, bees, and other insects in California. Research on other milkweed species has shown that soil nutrients and herbivory can affect the plant’s allocation of resources (e.g., slower growth in plants attacked by herbivores), but the impact of nutrient availability and insect damage on Narrow-leaved milkweed remains unclear. In this project, we carried out a field experiment to examine whether nutrient availability and herbivore density affect the growth and flowering time of this native species. We randomly assigned plants to three groups: control, low nutrient, and high nutrient (n = 20 per group). A fertilizer mix containing three primary nutrients (nitrogen, phosphorus, and potassium) was added to both nutrient treatments. At the beginning of the experiment, we used a paint brush dipped in a biodegradable soap solution to remove aphids attached to milkweed plants. All plants were watered twice per week throughout the duration of the experiment. Aphids were removed in mid-March 2024 and new aphid infestation (presence and abundance) was recorded in late April 2024. We measured the height and diameter of above-ground vegetative growth to compare growth rate among experimental groups. We also recorded the time of appearance of flower buds (an indicator of flowering time) in all plants. Our study provides insight into the effects of nutrient supplementation and aphid abundance on plant growth and flowering time of this native species. Additionally, we discuss how milkweed plants cope with herbivore attacks in their natural environment.

Poster Presentation

Session 1

9:15am – 10:30am
Grand Salon

Biology