Digital Commons Network^™

Investigating The Potential Utilisation Of Black Soldier Fly (Hermetia Illucens) As An Alternative Protein Source In Tilapia And Carp Feed, Sahya Maulu

School of Biological and Marine Sciences Theses

Three experimental trials were conducted to evaluate defatted black soldier fly (BSF; Hermetia illucens) larvae meal and BSF frass as alternative protein ingredients. Defatted BSF larvae meal was tested in diets for both Nile tilapia (Oreochromis niloticus) and mirror carp (Cyprinus carpio), whereas BSF frass was assessed only in Nile tilapia.In the first experiment, dietary inclusion of 20% and 40% BSF meal, replacing mainly soybean meal (SBM) and corn gluten meal (CGM), was evaluated in Nile tilapia over 5 weeks. BSF improved growth and feed utilisation in a dose-dependent manner, increased posterior intestinal fold length, muscularis thickness, and goblet cell …

Physiological And Morphological Responses To Drought Stress In Different Cultivation Environments In Wild Type And Aba-Deficient Barley, Chloe Betts

School of Biological and Marine Sciences Theses

Global food security is increasingly threatened by the effects of climate change. Of the environmental factors affected by climate change, drought is one of the most critical for plant survival and reproduction, shaping plant morphology and physiology and therefore crop productivity. Although the effects of drought on plants are widely studied, studies are often conducted in controlled greenhouse or laboratory conditions rather than more realistic field-like conditions. This is justified by the lower costs, convenience, and ability to disentangle the effects of different factors in more controlled conditions. This thesis explores the effect of the same watering limitations in different …

Assessing The Ecological Vulnerability Of Natural Flood Defences And Risks To Agricultural Land Following Seawater Flooding, Cally Barratt

School of Biological and Marine Sciences Theses

Anthropogenic climate change is intensifying extreme weather events, affecting the natural environment by altering ecosystems, and leading to habitat loss. Pressingly, the frequency and severity of storm surge flooding in low-lying coastal regions is projected to increase under future climate scenarios. There is a growing need to understand how these events will impact coastal ecosystems, and the measures that can be taken to mitigate against these effects and protect natural resources. Furthermore, with increased pressures placed on agriculture to meet food demand, protecting arable land resources in coastal regions from the rising threat of flooding is imperative. This thesis explores …

Coral Reef Fishes In Different Hard And Soft Coral-Dominated Reef Habitats, Ana Coelho

School of Biological and Marine Sciences Theses

Understanding how fish communities respond to different coral habitats is essential for predicting the future resilience of coral reef ecosystems. This study tested whether fish assemblages differ between hard and soft coral–dominated reef plots and among coral genera. We predicted higher fish abundance and more frequent benthic interactions in hard coral plots, and genus-specific differences in community composition, behaviour, and time spent within plots. This study examined fish species diversity, richness, abundance, behaviour, and the time spent in coral habitats. The analysis encompassed seven coral genera in an Indo-Pacific reef system. Twenty 2 × 2 m reef areas, each dominated …

Effects Of Salinity, Region, Site, And Cohort On Growth Traits Of The Black Mangrove, Avicennia Germinans, Bekki Foster

School of Biological and Marine Sciences Theses

Mangroves are trees that are adapted to grow in saline or brackish environments, typically, in estuarine and coastal zones in tropical and subtropical areas. Their root complexity supports marine biodiversity by providing habitat and nursery grounds for fishes and their canopies serve as roosting and breeding sites for avian species. Additionally, roots facilitate nutrient capture through epibiont communities and trap suspended sediments, enhancing stability against high-energy weather and contributing to vertical accretion, potentially mitigating sea level rise. This study aimed to investigate how such factors as salinity, provenance, and genetic background, affect the above and below ground morphological traits of …

Influence Of Ecological Transitions On The Evolution Of Circadian And Light Detection Genes In Squamates, Isobel Sleep

School of Biological and Marine Sciences Theses

Circadian rhythms are self-sustaining, endogenous processes that align behaviour and physiology with daily environmental cycles. Rhythms are regulated by conserved genes forming transcriptional feedback loops and are entrained by environmental cues (e.g., light). Circadian systems are well studied in model organisms, their molecular evolution in squamates (lizards and snakes) remains less understood. Squamates represent the most species-rich reptile group with extensive ecological and sensory diversity, exhibiting multiple independent transitions across ecological niches, including repeated shifts into low-light environments (e.g., nocturnality, fossoriality), making them ideal for examining circadian and light-associated gene evolution. This study investigates how ecological transitions have influenced the …

Coping With Climate Change: The Role Of Plasticity Within And Across Generations, Caitlin Mcandry

School of Biological and Marine Sciences Theses

Climate change is leading to increased mean temperatures and more frequent and severe temperature anomalies, threatening organisms globally. Phenotypic plasticity, the ability of a given genotype to express different phenotypes in different environments, may offer a mechanism that allows organisms to temporarily persist in a rapidly changing environment, ultimately buying time for genetically based adaptations to evolve. Plasticity has been demonstrated both within and across generations, in response to different environmental stressors. However, our understanding of the interactive effects of plastic responses across levels of biological organisation, and over temporal scales from hours to generations, is still limited. Additionally, we …

Trialing A Novel Method Of Skin Mucus Sampling To Measure Stress And Reproductive Steroid Hormones In Mobula Species Mobula Alfredi And Mobula Munkiana, Bethany Faulkner

School of Biological and Marine Sciences Theses

Anthropogenic pressures, exacerbated by exceptionally slow population growth, have led to all mobulid species being listed on the IUCN Red List. Understanding stress and reproductive physiology is essential for improving mobulid conservation strategies. However, few studies have investigated the hormonal processes that underlie stress responses and reproductive physiology in mobulids. Studies on fish species have identified positive correlations between steroid hormone concentrations in blood and skin mucus, the collection of the latter being a much less invasive technique. This pilot study examined the feasibility of using skin mucus as a non-invasive matrix for detecting steroid hormones in two mobulid species. …

Impacts Of Microplastics In A Changing Agri-Environment, Riley Kent

School of Biological and Marine Sciences Theses

Microplastics are increasingly recognized as persistent contaminants in terrestrial ecosystems, yet their impacts on plant performance remain poorly understood under realistic environmental conditions. In natural and agricultural systems, plants rarely encounter contaminants in isolation, instead experiencing multiple interacting stressors. The work presented in this thesis investigated how soil microplastics influence plant growth and physiology both independently and in combination with freshwater flooding, a climate-relevant stressor associated with increased storm activity and shifts in precipitation patterns. Using white clover (Trifolium repens) as a model agronomic legume across multiple cultivars, the study examined how polymer identity, plant genotype, and environmental context interact …

From Public To Policy How Jellyfish Data And Citizen Science Can Be Used For Biodiversity Management, John Terenzini

School of Biological and Marine Sciences Theses

Long term biodiversity data is necessary for detecting biological and ecological changes to marine ecosystems. The data can inform marine policy, yet data are often lacking for some species and traditional data collection approaches can be logistically challenging and expensive. Jellyfish are one taxon for which data are lacking, and data collection can be challenging due to their life history traits and the inherent challenges of marine research. This research aims to provide evidence for the importance of monitoring jellyfish, demonstrate the effectiveness of citizen science for monitoring jellyfish, and examine how jellyfish monitoring data can inform international frameworks. The …

Taking Snaps Of Plant Life Conditions: Designing A New Crop Autonomous Micro-Environmental Recording Array, Sohail Saeed

School of Biological and Marine Sciences Theses

Accurate measurement of plant microclimate is essential for understanding how local environmental conditions influence plant growth and response. In many experimental setups, environmental monitoring is performed using a single measurement point, which may fail to capture spatial variability across a plant array. This thesis presents the design, validation, and deployment of a compact distributed sensing system, referred to as C.A.M.E.R.A. (Crop Autonomous Micro-Environment Recording Array), developed to measure plant microclimate conditions at multiple locations simultaneously.The system integrates air temperature and relative humidity sensing using the SHT85, multi-point soil temperature measurement using DS18B20 probes, and relative light monitoring using the SEN0390 …

A Pilot Study Assessing The Oral Microbiome In Women Of Menopausal Age: Do Oral Nitrate–Reducing Bacteria Play A Role?, Katie Muddiman, Amazon Doble, Abish Stephen, Raul Bescos Garcia, Charlotte Illsley, Tomas Nicholas, Sally Hanks, Lisa Du Toit, Zoe Brookes

Peninsula Dental School

Introduction The links between oral health and female ageing are poorly understood, but many changes occur in the oral cavity of menopausal women that affect quality of life, and few current oral health interventions consider gender as part of their approach. The aim of this pilot study was to test the hypothesis that the oral microbiome and microenvironment change during female ageing and are thus worthy of further consideration both experimentally and clinically. Methods This observational pilot study retrospectively assessed women aged 18 to 89 years (n = 60) attending a UK primary care dental school facility for blood pressure …

Seeing Anxiety: Ecological Video Ethnography And Simulation To Understand Anxiety And Decision-Making In Dental Care, Mona Nasser, Hannah Drayson, Sally Hanks, Nicholas Peres, Michael Punt

Peninsula Dental School

BACKGROUND: Dental anxiety is a widespread barrier to care, often contributing to appointment avoidance, treatment disruption, and emotional strain for both patients and clinicians. While extensively studied as a psychological trait, less attention has been paid to how anxiety manifests situationally and relationally, through non-verbal, affective, and spatial cues within clinical encounters. Moreover, in certain contexts, such affective signals can intersect with decision-making processes, shaping how patients interpret, engage with, or withdraw from clinical choices.

OBJECTIVE: To explore how anxiety manifests within the micro-choreography of dental encounters, develop a taxonomy of 'anxious tells', and assess the utility of ecological video …

Quantifying The Response Of Bankfull Channel Width To Active Faulting In The Qianhe Graben On The Southwest Margin Of Ordos Block, China, Zhiheng Liu, Sarah Boulton, Suiping Zhou, Jianhua Guo, Tingting Wu, Wenjie Zhang, Ling Han

School of Geography, Earth and Environmental Sciences

River longitudinal profiles have been widely used to quantify the transient landscape response to active faulting, but the fluvial cross-section is often ignored, yet width can also reveal river incision and tectonic activity. Channel width responds to tectonic forcing through flow concentration effects resulting in channel narrowing where vertical incision dominates during uplift acceleration. Here we employ a novel bankfull channel width extraction method using Landsat and ZY-3 satellite images, and SRTM DEM data to evaluate the cross-section landscape response to active faulting in the Qianhe Graben of southwest Ordos, China. Although some areas are difficult to access (e.g., thick …

Presence And Characteristics Of Plastics And Microplastics On The Seabed Of The Western English Channel, Faye Read, Andrew Turner

School of Geography, Earth and Environmental Sciences

Little is known about the presence, distribution, origins and characteristics of plastic litter and microplastics on the ocean floor. In this study, plastics trawled from the bed of the western English Channel have been categorised and analysed by a variety of optical and spectroscopic techniques. A total of 90 plastic samples were classified, in descending order of abundance, as food-drink packaging, unknown, homeware, military and fishing. Most samples showed varying degrees of weathering (e.g., discolouration, distortion, cracking, fragmentation) and were visibly fouled by calcareous deposits. The majority of samples were constructed of polymers of negative buoyancy (e.g., polyamides, polyethylene terephthalate …

Direct And Indirect Metal Contamination Of Estuarine Sediments By Boat Paint Particles, Andrew Turner, Ho Kwan Cheung

School of Geography, Earth and Environmental Sciences

Surface and subsurface estuarine sediments close to a cluster of abandoned boats have been fractionated (between <250 and 5000 μm) and analysed microscopically for paint particles. Paints were encountered in all samples, with concentrations calculated for whole sediment samples up to 1450 per kg (dry weight). X-ray fluorescence (XRF) analysis of paint particles retained by the coarsest (>5000 μm) size fraction revealed heterogeneous concentrations of Ba, Cu, Pb, Sn and Zn that reflect pigments and antifoulants used in various recent and historical antifouling and above waterline boat paints. Analysis of sediments by XRF revelated heterogeneous distributions of these metals between locations, size fractions and depths, and among replicate measurements at different positions of the same sample. Consequently, no relationship with grain size (evaluated using Rb as a proxy) was evident and concentrations often greatly exceeded predicted effect levels for sediments. Re-analysis …