Thesis Defenses

"Into the Deep: Impacts of Natural and Artificial Substrates in the Deep Sea"

A Thesis Defense by Sydney Mcdermott

Invertebrate Ecology Lab

Zoom | Live-Stream | December 13th, 2023 at 10:00 am PDT

Abstract

With increasing maritime activities, man-made structures such as oil platforms, wind farms, and lost shipping containers are becoming ubiquitous in the oceans. These structures serve as substrates for marine organisms. There is evidence that unique communities develop on some man-made structures; however, the effects of substrate type vary, and are often confounded with geography and depth. Man-made objects lost in shallow water have a better chance of being retrieved than those in the deep sea, resulting in the deep sea becoming a semi-permanent repository. We studied invertebrate communities on a lost shipping container found at 1.3 km depth and deployed experimental substrates at 200 m depth to assess whether colonization and succession differ between natural and artificial substrates in the deep sea. The community on the lost container changed over time, becoming more similar to the communities on naturally occurring substrate in the Monterey Bay Submarine canyon with dominance by echinoderms, cnidarians, poriferans, and small mollusks. Communities on the experimental artificial substrates were similar to those found on experimental natural substrates, with no significant difference in diversity, richness, or evenness based on substrate type. There was a significant difference across all experimental substrates over time, indicating that the substrates may have undergone successional changes at similar rates with a major shift after 5 years. Lost objects may serve as substrates for communities mostly similar to those that form on naturally occurring hard substrates, making anthropogenic pollutants a potential subject of future monitoring efforts.

Bio

Sydney received her B.S. in marine science from the University of Maine in 2020 before attending Moss Landing Marine Laboratories. She has worked on a variety of projects across different marine habitats, from studying the microbiome of an east coast intertidal alga, to monitoring harmful algal blooms in the Pacific Northwest, to investigating the changes in sea sponge populations in the Bering Sea over the past 5 million years. Her research at MLML under the guidance of Dr. Amanda Kahn focuses on the impact of lost anthropogenic objects in the deep sea, specifically lost shipping containers. Sydney also began a PhD in ecology and evolution at the University of Louisiana at Lafayette in the fall of 2023.

"The Feeding Habits and Selectivity of Siphonophores in Monterey Bay"

A Thesis Defense by Alex Lapides

Invertebrate Ecology Lab

Zoom | Live-Stream | November 27th, 2023 at 12:00 pm PDT

Abstract

Gelatinous zooplankton are historically understudied and we have much to learn about how they fit into the larger food web.  Of gelatinous zooplankton, siphonophores are especially known to have broad diets and to select for a wide variety of prey.  In this study we investigated siphonophore feeding habits using a long-term remotely operated vehicle video dataset from the Monterey Bay, CA.  In addition, we quantified the degree of specialization for each siphonophore-prey pair, and we investigated the relationship between genetic distance and specialization differences.  We found siphonophores tended to belong to one feeding guild and in some cases fed exclusively on one prey.  Siphonophores also selected strongly for a few specific prey.  We found a slight relationship between genetic distance and siphonophore specialization.  Overall, this study upholds previously known trends about siphonophore diet, selectivity, and phylogenetic patterns and expands our knowledge of the midwater food web.

Bio

Alex received her B.S. in Ecology and Evolution from UC Santa Cruz in 2018 before coming to MLML in the Fall of 2020.    She has held a variety of technician positions ranging from research vessel operations to molecular lab work to machine learning, and has studied a variety of habitats ranging from salt marshes to the deep sea.  Overall, she is most interested in problems concerning the open ocean that leverage large datasets and statistics to make inferences about the environment, and is most content behind a computer playing in R.  In her free time, Alex likes to perform aerial silks, spin fire, and play Magic: the Gathering

"Drivers of intertidal purple sea urchin (Strongylocentrotus purpuratus) reproductive capacity and the implications for kelp forest recovery"

A Thesis Defense by Isaak Haberman

Invertebrate Ecology Lab

| Live-Stream | December 8th, 2023 at 3:00 pm PDT

Abstract

Kelp forests are integrally important ecosystems along eastern Pacific coastlines, sequestering carbon, reducing wave erosion, and increasing biodiversity in coastal marine communities. However, kelp forest coverage in central California has experienced major decline in the past decade, being replaced with unproductive urchin barren habitats. The factors affecting the establishment and persistence of urchin barrens have been extensively researched in the subtidal, but the influence of intertidal sea urchin populations is unknown. Moreover, intertidal populations are likely connected to subtidal communities via larval dispersal, so an understanding of intertidal urchin reproductive dynamics is important. I collected urchins and biological and environmental data from nine sites along the Monterey Peninsula in central California with varying algal communities, urchin densities, and wave exposures. I weighed and extracted the gonads from urchins at each site to measure gonadal somatic index (GSI%), a representation of reproductive capacity proportional to urchin size. I found that intertidal urchin reproductive capacity is unrelated to coralline algae cover or urchin density; contrary to what is seen in the subtidal. There is a weak positive relationship between fleshy algae coverage and reproductive capacity. Moreover, urchins collected from sites that had higher drift algae presence exhibited higher reproductive capacities. This indicates that urchins in the intertidal are resilient to poor fleshy algae coverage where they are living because drift algae is continually deposited into intertidal environments for them to consume. Therefore, the intertidal can support higher densities of healthy sea urchins that may represent an important contribution of urchin larval supply to subtidal urchin barrens. Kelp restoration efforts must be amended to include intertidal areas - especially those of high urchin densities - in order to maximize their efficacy.

Bio

I am a graduate student at CSUMB and MLML advised by Alison Haupt and co-advised by Amanda Kahn. I completed my undergraduate degree at the University of British Columbia where I studied marine biology and did research on the caloric value of different seaweed species. My thesis at CSUMB focuses on the reproductive capacities of intertidal populations of purple sea urchins (Strongylocentrotus purpuratus) and how these populations are important to consider for kelp forest restoration techniques. My research interests are nearshore community ecology, applied ecology, and generally how species interactions and habitat shape the species composition of different nearshore areas. After I graduate, I will be teaching at CSUMB in the spring. In my spare time I like doing crossword puzzles, going camping and climbing, and watching the Packers.

"Habitat-mediated efficacy of 360 degree diver-operated video for quantitative surveys of California reef fishes"

A Thesis Defense by Kameron Strickland

Ichthyology Lab

Zoom | Live-Stream | November 13th, 2023 at 3:00 pm PDT

Abstract

Temperate rocky reefs feature a mosaic of complex macrohabitat features which host a variety of demersal fish species. Giant kelp forests add considerable vertical structure to rocky reefs, including macrohabitats extending from the reef to the upper water column. Much of what we know about temperate communities derives from shallow SCUBA surveys in which divers record observations using underwater visual census (UVC) techniques. Increasingly, these communities are being studied with video techniques first utilized in deeper water. While UVC provides immediate data on fish communities and requires no additional technology either for data collection or post-processing, imagery captures the fine-scale associations between fish specific habitat features that elude UVC techniques. While traditional video cameras constrain the field of view available to a UVC diver, 360˚ cameras record everything in all directions, eliminating the need to selectively survey one direction underwater. However, questions remain as to how data derived from 360˚ video transects compare to the more well-established UVC transects, particularly in complex environments. My primary research objective was to examine the trade-offs associated with 360˚ video and UVC when quantifying attributes of the demersal fish community across multiple sites and macrohabitat types. I performed SCUBA dives at four sites around the Monterey Peninsula in central California. Pairing UVC and 360˚ video, I recorded fish counts along 30 meter demersal transects. Richness, diversity, abundance, and density of fishes from UVC and 360˚ video were compared statistically with two-way analysis of variance (ANOVA) and non-metric multidimensional scaling (NMDS). Results indicate that within fish-habitat guilds, counts of species were similar between methods at all macrohabitats and most sites. 360˚ video and UVC produced similar results with respect to species richness and diversity. Differences between the methods arose by looking at density at any scale, as well as total count per meter of all fishes. These results suggest that with some caveats, 360˚ video transects can be incorporated into temperate subtidal reef monitoring without compromising data quality.

Bio

Kameron graduated with his B.S. in Marine Science from CSU Monterey Bay in 2019. There, he was heavily involved in the SCUBA program, both volunteering for courses and diving for his personal capstone project. Early discussion of Kameron's thesis project was already in progress when he joined the Ichthyology lab in 2020. After learning to create 360˚ video SCUBA dives, Kameron wanted to put the technology through trials and see how 360˚ video transects surveyed kelp forest fish compared to SCUBA divers. During his time at MLML Kameron performed video analysis for the Fisheries and Conservation Biology Lab's BOSS video lander project at San Clemente Island, became a SCUBA Instructor, started a marine consulting job, and even worked as a long-term substitute teacher across multiple grade levels. In his free time, Kameron enjoys wildlife photography and can be found taking cameras precariously close to seawater.

"Spatiotemporal Dynamics and Biogeochemical Responses in a Tidally Restricted Moro Cojo Slough"

A Thesis Defense by Ryan Chiu

Physical Oceanography Lab

Zoom | Live-Stream | November 8th, 2023 at 3:00 pm PDT

Abstract

Four years of observational data for Moro Cojo Slough (MCS), a Mediterranean climate estuary in central California, linked anthropogenic nutrient loading and hydrological modifications to a shift in net ecosystem metabolism (NEM) that differs from the characteristic net heterotrophic behavior of most estuarine systems. A lack of precipitation and limited flushing during the dry seasons, as evidenced from hypersaline waters, contribute to high ecosystem respiration rates that drove NEM to nearly balanced or net autotrophic. During the wet seasons, increased runoff and nutrient loading due to precipitation elevated primary production rates within MCS, characterizing the system as net autotrophic. Box models developed for the estuary determined that: 1) salinity was primarily controlled by advection and runoff, 2) high nitrate fluxes were advected into the slough at the mouth, and 3) the processes that dominate DO fluxes were biological processes and gas exchange. Field deployments of DO loggers further reinforced this dependence on daytime primary production and nighttime ecosystem respiration, as observed in the diurnal variabilities in DO. With anthropogenic factors playing a critical role in MCS’s net autotrophic characterization, there is concern that heavily modified systems may begin to exhibit a shift in metabolic behavior and ultimately act as a net source of carbon.

"White Abalone (Haliotis sorenseni) Restoration Aquaculture: An Assessment of Formulated Diets and Probiotics"

A Thesis Defense by Kayla Roy

Aquaculture Lab

Zoom | Live-Stream | July 17th, 2022 at 12:00 pm PDT

Abstract

White abalone (Haliotis sorenseni) are an endangered species found along the California coast. They are at historically low densities, nearing extinction. Aquaculture facilities throughout California are currently involved in the captive breeding of the species and grow out of juveniles for outplanting to wild habitat. White abalone have historically suffered from an infectious bacterial disease known as withering syndrome or Ca.Xc. This disease has been treated with an antibiotic, but antibiotic treatments can lower immune functions and create antibiotic resistance genes. A probiotic treatment could be used to replace this antibiotic and increase the overall health and growth rates in white abalone. To study the use of probiotics, Bacillus licheniformis was used on macroalgae in abalone exposed to and unexposed to Ca.Xc There was no Ca.Xc detected in any of the white abalone at the end of the study indicating that white abalone may now be able to combat Ca.Xc with abacteriophage (pCXc). Shell loss during this first probiotic experiment hindered data collection on feeding and growth rates. In the first probiotic study 42% of the white abalone and 53% of the red abalone lost their shells. Two subsequent studies were conducted to understand the cause of the shell loss. These studies were inconclusive, but one of these experiments showed that low tank stocking density (588 abalone/m2) can increase feeding and growth rates compared to high tank densities (1,176 abalone/m2).

White abalone restoration activity aims to enhance the species recovery by developing self-sustaining populations. These efforts are costly because of the species’ slow growth, high early mortality rate, and reliance on seasonal macroalgae feed. These limiting factors warrant an assessment of alternative diets and probiotic treatments for the species to shorten the culture time and lower costs before outplanting. Diet administered probiotics have previously shown improved growth rates, feed digestibility, and survivorship in abalone species. Formulated feeds are known to provide adequate nutrition and reduce costs for several cultured species. The second probiotic study investigated the effects of B. licheniformis on a commercially formulated abalone feed, ABKelp®, on white abalone. Three diet treatments were assessed: formulated feed treatment, formulated + probiotic treatment, and standard fresh macroalgae diet (Devaleraea mollis and Macrocystis pyrifera). The standard fresh macroalgae treatment resulted in the highest growth rates and feed intake, while the formulated + probiotic treatment had the lowest feeding and growth rates. This could be due to a reduced palatability caused by the presence of the probiotic.

Despite comparatively inferior growth metrics, the formulated treatment still resulted in adequate growth andsurvivorship in white abalone. The use of a formulated diet is feasible for white abalone restoration aquaculture when considering additional costs associated with fresh macroalgae feeding including permits, diving, and boat operations for M. pyrifera collection and culture facilities devoted to macroalgae culture and storage. The growth rates, feeding rates, and proximate analysis suggest that formulated feed is a viable alternative diet for conservation aquaculture facilities with limited access to fresh macroalgae.

Bio

Kayla graduated from California State University Monterey Bay (CSUMB) in May of 2019 with a B.S. in Marine Science. In her undergraduate time there she served as president of the Marine Science Club and was a TA the Beginner and Advanced/Rescue SCUBA classes. She volunteered a Science Mentor for Watsonville Area Teens Conserving Habitats (WATCH) program through the Monterey Bay Aquarium.

Kayla accepted a position in Dr. Luke Gardner’s lab at MLML in the fall of 2019. Her thesis investigated multiple methods of improving white abalone aquaculture restoration work. In her thesis she assessed the use of a probiotic treatment for withering syndrome now known as Ca.Xc. She assessed a formulated diet to understand its impact on white abalone growth rates, feeding rates, and survivorship compared to their natural and seasonally limited seaweed diet. She presented her thesis work at the Aquaculture America 2023 conference in New Orleans, Louisiana. During her thesis work she mentored an undergraduate student though the CSUMB Undergraduate Research Opportunities Center (UROC) program. Kayla worked as a water quality monitoring technician and worked on the White Abalone Project during graduate school. She reared the white abalone at MLML for outplanting and helped with abalone spawning work. She served as the GA for the Invertebrate Zoology I course at MLML. During her time at MLML she participated in the 2023 research competition AlgaePrize at the National Renewable Energy Lab (NREL) in Golden, Colorado. After graduating Kayla is looking forward to continuing with aquaculture work and research.

"Influence of intrinsic factors on at-sea behavior of late chick-rearing emperor penguins (Aptenodytes forsteri) at Cape Crozier, Ross Island, Antarctica"

A Thesis Defense by Parker Forman

Vertebrate Ecology Lab

Zoom | Live-Stream | July 19th, 2022 at 12:00 pm PDT

Abstract

I described the at-sea behavior of emperor penguins (Aptenodytes forsteri) during late chick-rearing at Cape Crozier. Analyzing data from eight penguins, I investigated how intrinsic factors, including sex, size, and body condition influenced their behaviors. Penguins exhibited mean trip durations of 10.6±3.4 days, covering a daily distance of 55.7±8.0 km. Penguins predominantly performed dives within the upper 200 meters of the water column (90.7±26.5%), with a smaller proportion of dives (9.3±2.0%) reaching greater depths. Deeper dives were typically associated with shallow bathymetry. Penguins conducted an average of 1,860±681 dives with maximum depths of 455.8±32.6 m and durations of 12.9±2.4 minutes. Penguins spent 66.4±14.8% and 43.9±4.4% of their time at sea resting and diving.

Penguins with similar behaviors were categorized into groups: Group I foraged near the continent and traveled to the Ross Bank, and Group II predominantly foraged near the continent. I found significant differences in foraging behaviors between the groups and sexes. The composition of these groups was influenced by sex. Group I mostly comprised males, while Group II were females and one unknown sex. Females displayed higher dive frequencies per day (Females (F):186±17, Males (M):151±4), shallower maximum depths (F: 432.2±29.4 m, M: 476.8±12.8 m), and shorter durations (F: 3.2±0.7, M: 3.9±0.3). Possible explanations for the observed differences between male and female penguins include energetic requirements, prey preference, physical characteristics, and niche differentiation, which can shape their distinct foraging behaviors.

Furthermore, results from this study indicate that penguin behaviors were also influenced by the physical characteristics and condition of their bodies. This finding suggests that there may be an optimal body condition for achieving greater diving depths. Penguins with intermediate body conditions may possess a more efficient physiological adaptation for sustained deep diving, enabling them to access resources inaccessible to individuals with lower or higher body compositions.

This study advances our understanding of late-chick-rearing penguins and the influence of intrinsic factors on their behavior. The findings indicate that emperor penguins exhibit divergent strategies influenced by sex and physical condition, leading to variations in dive behavior and bathymetry use. These sex-based disparities in penguin behavior highlight distinct ecological roles for each sex within the species. These findings provide a novel description that underscores the remarkable adaptations of emperor penguins in successfully navigating dynamic environments at Cape Crozier.

Bio

Parker Forman is an ecologist recognized for his creative application of datalogging technology to study cryptic species. With a solid understanding of behavioral ecology, Parker illuminates the hidden complexities of these creatures' lives and their interactions with their environments.

After completing his undergraduate studies, Parker embarked on a hands-on role as a biological field technician. His work encompassed diverse demographic studies, contributing to our knowledge of marine and terrestrial vertebrates, including Northern spotted owls, native Hawaiian birds, Northern elephant seals, and fur seals.

In 2018, Parker joined the Vertebrate Ecology Lab at MLML, which marked a turning point in his career. He researched the frigid landscapes of Cape Crozier, Antarctica, focusing on studying the at-sea behavior of emperor penguins. Living in such an isolated location alongside his study subjects provided Parker with firsthand experiences of the lives of these deep-diving seabirds.

Guided by his passion for nature, data analysis, and commitment to conservation, his experiences reinforce his dedication to expanding conservation efforts in ecological discovery.

"Composition and Distribution of Fish Assemblages in Cap de Creus Natural Park in Relation to Marine Protection, Depth, and Habitat"

A Thesis Defense by Katie Cieri

Fisheries and Conservation Biology Lab

Zoom | Live-Stream | Arpil 19th, 2022 at 4:00 pm PDT

Bio

Katie got her B.S. in Biology from the University of Virginia. After graduating, she pursued many different opportunities. She completed a Research Apprenticeship at Friday Harbor Laboratories investigating the foraging ecology and diet of Pacific Sand Lance. She also worked as an intern with the Virginia Aquarium Stranding Network in the Humpback Whale identification program. Prior to her enrollment in MLML, Katie worked as a research technician and lab manager in the Farmer Lab at the University of Utah, where she conducted investigations into the respiratory physiology of Tarpon and American Alligators. While completing her Master’s thesis, the composition and distribution of fish assemblages in Cap de Creus Natural Park in relation to marine protection, depth, and habitat, at MLML Katie worked as a research technician in the Fisheries and Conservation Biology Lab under Dr. Rick Starr. She was involved in many projects, including the Monitoring & Evaluation of Mid-Depth Rocky Reef Ecosystems, the Benthic Observation System Survey (BOSS), and the California Collaborative Fisheries Research Program (CCFRP). Through these projects and her own thesis, Katie explored how different survey methodologies including video landers, remotely operated vehicles, and hook-and-line surveys, can be utilized to assess nearshore fish and invertebrate communities and to monitor the effectiveness of Marine Protected Areas. Katie is also passionate about outreach and inclusion and continues to explore avenues to make marine science more accessible. While at MLML, she was a member of the leadership committee for the Monterey Bay Chapter of the Society for Women in Marine Science. She also contributed to MLML Open House through leading crowdfunding, participating in the puppet show, and heading up the donations committee. Katie is interested in exploring the best solutions for marine conservation through science, user engagement, and collaborations in her new position as a California Sea Grant Fellow for the California Ocean Protection Council's Biodiversity Program. In her free time, Katie enjoys kayaking, scuba diving, hiking, and adventures with her husband and dog.