Honours Theses

Permanent URI for this collection

https://unbscholar.lib.unb.ca/handle/1882/12781

Browse

Now showing 1 - 20 of 73

A retrospective assessment of marine ecological research using optimal α
(University of New Brunswick, 2020) Zhao, Chuhan; Houlahan, Jeff
Null hypothesis significance testing (NHST) is and has been for many decades broadly applied across disciplines, NHST’s shortcomings have been identified and discussed since its introduction. Optimal alpha is a better method for setting statistical thresholds in NHST because it minimizes the overall probability of making errors. However, we don’t know how often using optimal α would result in a different conclusion than NHST. I calculate optimal α for 433 tests from 2009-2018 published marine biology papers and compare conclusions with NHST. I find totally 24 % of conflicting results (small ES: 22 %; medium ES: 22 %; large ES: 29 %). For disagreement, optimal alpha has 97 % significant results at small ES, 54% at medium and 24% at large. Low observed p value tends to have disagreement. These results mean that failing to use optimal alpha may be inflating the probability of making wrong conclusions in marine biology.
An Assessment of Inner Bay of Fundy Atlantic Salmon (Salmo salar) Spawning Success in Fundy National Park
(University of New Brunswick, 2023-04) Nason, Jack S. J.; Samways, Kurt M.; Pavey, Scott A.
Atlantic salmon (Salmo salar) have declined precipitously throughout most of their North American range. As a result, many strategies have been implemented to try and restore Atlantic salmon (Salmo salar). One such restoration strategy, implemented by the Fundy Salmon Recovery project, involves the collection of endangered inner Bay of Fundy salmon smolts from their natal rivers to be reared at the world’s first marine conservation farm to maturity. This strategy includes both an open net ocean pen and freshwater hatchery components. Upon maturity, these salmon are returned to their natal rivers as adults. This release may be done by hand, by carrying the sexually mature salmon to the water or by carefully lowering them into pools using a helicopter, so they can naturally spawn. In my study, I aim to determine whether these differences in rearing and release strategies led to significant changes in offspring production in the adults of two Fundy National Park rivers. Single nucleotide polymorphisms (SNPs) at 185 loci were used to match parents with the next year’s offspring using Colony, a parentage analysis software. Using a fixed effects linear model, I found that there was no significant effect on offspring production caused by release strategy in both rivers. On the Point Wolfe River, rearing strategy was found to have a significant effect on offspring production – with marine-reared adults out-performing freshwater reared adults. This suggests that the marine-rearing strategy, implemented by the Fundy Salmon Recovery project can outperform, in some cases the more traditional freshwater rearing strategy in terms of releasing high-fitness adult Atlantic salmon.
An in vitro evaluation of the antibiotic and antimycotic properties of the colletotrichamides, a family of novel polyketide natural products
(University of New Brunswick, 2025-03) Kline, Madeline; Dr. Christopher Gray
The rise of antibiotic-resistant bacteria poses an alarming global health crisis, necessitating the urgent development of novel antimicrobial agents. We have recently discovered a new family of antibiotic polyketides, the colletotrichamides A-E, that were isolated from an endophytic Colletotrichum species fungus. In this study we evaluated the antibiotic activity of the colletotrichamides against a panel of 10 bacterial and fungal pathogens using absorbance- and fluorescence-based in vitro bioassays. Compounds that inhibited microbial growth by more than 90% in preliminary screening assays underwent dose-response analysis to determine their IC50 values. Colletotrichamide C demonstrated the highest activity overall, exhibiting strong inhibition against Candida albicans and Enterococcus faecium. Our results indicate that the colletotrichamides have the potential to contribute to the development of novel antimicrobial agents and, although further research is needed to elucidate their mechanisms of action and in vivo efficacy, underscores the importance of natural product research in antibiotic discovery efforts.
An inside look at a professional modern dance company
(University of New Brunswick, 2016) MacMillan, Marissa; Burns, Janet Mary Christine
This thesis explores the experiences and collective activity of participants in the art world of Bodies in Motion, a local modern dance organization from Hartford, Chilton. This qualitative research uses Becker’s (1982) framework for studying social organizations, in conjunction with Unruh’s (1979) theory of social worlds and social types, to understand how participants create and maintain the functioning of their social world. The research followed a symbolic interactionist, theoretical approach, where data was collected through interviews and participant-observation. Through these techniques, eleven participants were asked about their experience with Bodies in Motion and the art sphere within Hartford. The research found that Becker’s framework and Unruh’s social types can help to determine the dynamics of social worlds.
Assessing Predictive Ability of Species-Area Relationship Models
(University of New Brunswick, 2022-04) Yoo, Philip J.; Houlahan, Jeff
The species-area relationship (SAR) is a well-established concept but there is still limited understanding of its predictive ability. I investigated the predictive ability of four SAR models (species/area, log-species/log-area, species/log-area, and log-species/area) to new data using linear regression models. I collected 84 SAR datasets and broke them into training and test sets. For each training set I estimated the slope and intercept for each of the 4 SAR models and then used these estimates to predict species richness in each of the 84 test sets. The predictive ability of SAR models for 68 of the 84 was more accurate than the mean. Whether I was assessing the transferability of SAR models in space (i.e., a model built using data from one geographical location in order to predict onto another location) or non-spatially (i.e., model built using randomized sites to predict richness to sites nearby) the predictive ability was similar.
Assessing the number of known-age chicks required for accurate age estimation of growing Atlantic Puffin (Fratercula arctica) and Razorbill (Alca torda) chicks
(University of New Brunswick, 2022-04) Braschuk, Arika; Major, Heather
At Machias Seal Island, chick age is used to estimate hatch dates and predict fledge dates of growing seabirds. A small percentage of chicks have a known hatch date, as the number of nest checks required to capture hatch date is limited to reduce colony disturbance. The goal of this study is to find the minimum number of known-age chicks required to accurately estimate ages of unknown-age chicks in Atlantic Puffins (Fratercula arctica) and Razorbills (Alca torda). To do this, I collected measurements of known-age chicks from the time series at MSI (1995-2021), separated these data into training and test datasets, created a series of annual linear growth models, estimated the ages of known-age chicks, and calculated the accuracy of these estimates. My results suggest that a minimum of three chicks are required to estimate chick age with 85% accuracy of puffins and four chicks for 80% accuracy in Razorbills.
Audial, visual and statistical discrimination of similar calls made by sei and blue whales
(University of New Brunswick, 2025-03) MacDonald, Kerkeslin; Dr. Kimberley Davies; Dr. Katherine Indeck
In the Gulf of St. Lawrence (GoSL), current near real-time acoustic detection methods for baleen whale calls are misclassifying blue whale (Balaenoptera musculus) acoustic presence as sei whale (Balaenoptera borealis), likely due to their similar calls and the lack of a blue whale call library in the low-frequency detection and classification system (LFDCS) used to inform near real-time analysis protocols. This study aimed to quantify misclassifications using manual analysis of archival data and to determine how LFDCS classifications change with a blue whale call library incorporated. Data were collected from 8 glider deployments in the GoSL from 2020-2023. Manual analysis revealed sei whale acoustic presence was correctly identified by near real-time detection methods 1-3% of the time. Furthermore, analyses with the expanded call library resulted in LFDCS correctly classifying 31% of manually validated blue whale periods. Updating the near real-time analysis protocols will be critical for improving acoustic detections.
Bioautographic fractionation of antibiotic natural products from a marine-derived fungus
(University of New Brunswick, 2024-04) Newlands, Camryn R.; Gray, Chrisopher A.
The development of antibiotic resistance in recent decades is a major concern that has urged natural product researchers to investigate new biological sources of antimicrobial compounds. Fungi isolated from marine environments have proven to be a potent source of bioactive molecules. The crude extract of an unidentified seafoamderived fungus, SC1-077G, demonstrated strong inhibition of Staphylococcus aureus in an antimicrobial activity screening in 2016. The objective of this research was to isolate the compound(s) responsible for the bioactivity of the crude extract using immersion bioautography guided fractionation. Flash chromatography and high-performance liquid chromatography generated an impure sample containing two putatively new natural products, which demonstrated strong inhibition of S. aureus, that could not be further purified chromatographically. Acetylation of the impure sample facilitated the isolation of two acetylated, putatively new natural product derivatives. Immersion bioautography proved to be an efficient method for directing the fractionation of bioactive natural products.
Change in occupancy and density of nesting Atlantic puffins and razorbills on Machias Seal Island between 2011 and 2019
(University of New Brunswick, 2020) Elisseou, Meredyth; H. Major
At Machias Seal Island (MSI), populations of nesting Atlantic Puffins (Fratercula arctica) and Razorbills (Alca torda) are stable and increasing (respectively). The purpose of my study was to determine whether the increasing Razorbill population has caused a change in the spatial distribution of nesting puffins on the island. I hypothesized that the larger, more competitive Razorbills outcompete puffins for nesting space, resulting in the movement of puffins to alternative regions of the island. Using data from Alcid surveys that occurred in 2011, 2015, 2016, and 2019, I assessed occupancy and density of puffins and Razorbills in each of 1,753 surveyed quadrats. Using generalized linear models in an information theoretic approach, I found no changes in occupancy or density of either species. However, I note the short timespan (eight years) covered in my study and suggest that continued monitoring and analysis of changes in puffin and Razorbill occupancy and density.
Changes in body size of Atlantic Puffins at Machias Seal Island (MSI) from 1995-2019
(University of New Brunswick, 2020) Georgantopoulos, Joy; Major, Heather
Body size of fledging Atlantic Puffins (Fratercula arctica) at Machias Seal Island have been decreasing over the past 25 years (1995-2019) likely due to climate change. Using fledging size data archived in the Microsoft Access data base “seabird finder” I asked three questions: 1) have puffin fledgers gotten smaller in size (wing chord and mass) over the last 25 years, 2) can small fledgers continue to grow (in wing chord) after leaving the island, and 3) are adult Atlantic Puffins decreasing in size (wing chord). Using linear regressions, I found support for the hypothesis that fledgers are getting smaller with time and that small fledgers grow more after leaving the island than large fledgers. Finally, I found a marginally insignificant result suggesting that adult size is changing in response to fledging size (i.e., adults are becoming smaller with time).
Childhood Trauma and Substance Use in an Undergraduate Population: Revisiting the Role of Impulsivity
(University of New Brunswick, 2025-04) Scherf, Julia; Caroline Brunelle
The comorbidity between traumatic childhood experiences and subsequent substance use has been well established. Negative urgency is defined as a need to act rashly in response to negative emotions, and positive urgency is the urge to act impulsively in the context of positive emotions. The purpose of this study is to explore if negative and positive urgency partially account for the relationship between childhood trauma and the use of substances in university students. A total of 209 students (Mage = 20.81, SD = 4.68) were recruited from the University of New Brunswick and completed a questionnaire package online, which included measures of childhood trauma, urgency, frequency of substance use and problematic use of various substances. Results showed significant positive correlations between childhood trauma and cannabis/alcohol problems, between childhood trauma and positive and negative urgency and between alcohol and cannabis problems and positive and negative urgency scores. Mediation analysis showed a significant indirect effect of negative urgency between childhood trauma and alcohol problems, but not for cannabis problems. The study suggests that interventions that reduce negative urgency may be promising to mitigate the effects of trauma on substance use behaviours.
Comparative Analysis of Cytokine Levels in Multiple Myeloma Patients: Implications for Natural Killer Cells and Therapeutic Monoclonal Antibodies
(University of New Brunswick, 2024-04) Lee, Sungmok; Reiman, Tony
Multiple myeloma (MM) is a lethal cancer affecting bone marrow (BM) plasma cells, with dysregulated natural killer (NK) cells and cytokine production contributing to disease progression. Monoclonal antibody therapies (mAbs) can induce NK cell responses against tumours, which can potentially be enhanced by cytokine manipulation. This study evaluates cytokine levels in MM patients’ blood compared to the blood of healthy controls (CTR) and the BM of MM patients to assess their potential as therapeutic targets. Using Bio-Plex profiling, eight cytokines (IL-2, IL-8, IL-10, IL-12, IL-15, IL-18, IFN-γ, and TGF-β1) were quantified. Significant differences in cytokine profiles were observed between MM patients and CTR, as well as between MM patients' blood and BM. These findings underscore cytokines’ potential role in MM progression, emphasizing them as potential therapeutic targets. The study lays the groundwork for future research aimed at modulating the cytokine network in MM to augment NK cell responsiveness to mAbs.
Comparing the effectiveness of protein coding genes to the ITS gene as DNA barcode markers for species-level identification of Penicillium and Aspergillus fungal isolates
(University of New Brunswick, 2020) Po, Hui Ting; Gray, Christopher; Johnson, John
Penicillium and Aspergillus are important genera of fungi in the order Eurotiales that are species-rich and are found living ubiquitously. The ability to identify these fungal species allows researchers to collate and access valuable information associated with these fungi. In recent years, a molecular technique known as DNA barcoding has become a common method used for fungal identification. The internal transcribed spacer (ITS) gene was described in 2012 as the universal DNA barcode marker for fungal identifications but has limited sequence variability to identify species of Penicillium and Aspergillus. Protein coding genes; benA and calmodulin may be more effective barcode markers for identifying Penicillium and Aspergillus species, respectively, due to higher interspecific variations in the gene sequences. In the present study, we compare whether it is more effective to identify Penicillium and Aspergillus fungal isolates to the species level using protein coding genes or the ITS gene as barcode markers.
Contribution of variability in embryo development rate and status at hatch to the protracted hatch period of female American lobster Homarus americanus
(University of New Brunswick, 2018) White, Lydia; Rochette, Rémy; Zou, Liwen
Female American lobsters typically hatch their embryos over protracted hatch periods of 15-32 days. To investigate the mechanisms underlying this intra-brood variation in hatch time, I reared individual embryos from June to September 2017 at a constant temperature of 9°C, took photos of them at the beginning of the study and prior to hatch, and measured their eye size as a proxy of their development status. A multiple linear regression model explained 74% of the variability in hatch day, and indicated that embryos that hatcher earlier in the summer are (i) more developed come spring (44% of explained variance), (ii) less advanced in development (28%), and (iii) develop at a faster rate (27%). This study suggests that the process of hatching is not strictly associated with a particular role of the brooding female, but rather is perhaps mostly a function of processes or attributes of individual embryos.
Cross-shelf variation in habitat characteristics of arctic whales in Baffin Bay measured using ocean gliders
(University of New Brunswick, 2025-02) Mueller-Classen, Keely; Dr Kimberley Davies
Zooplankton distribution and abundance play a crucial role in shaping the foraging behavior of bowhead whales, Balaena mysticetus, in Arctic marine ecosystems. Understanding how physical oceanographic conditions influence the vertical and horizontal zooplankton abundance is essential for assessing critical foraging habitats. In this study, we analyzed depth-integrated zooplankton abundance and maximum zooplankton abundance across distinct water masses on and off the West Greenland continental shelf using Cabot 198 ocean glider. The glider transited along six transects that travelled cross-shelf, collecting 176 vertical profiles of zooplankton abundance and environmental variables including temperature, salinity, and bathymetric depth. Zooplankton were primarily concentrated within the upper 300m of the water column, with diel vertical migration (DVM) observed, as aggregations shifted from the top 100 m at night to depths below 200 m during the day. Bathymetric depth was a significant predictor of total depth-integrated zooplankton abundance (individuals/m², p < 0.001). The highest zooplankton densities were recorded in association with Arctic and Atlantic Waters. These findings suggest that Arctic and Atlantic-influenced waters provide key foraging grounds for bowhead whales by supporting prey densities exceeding previously established foraging thresholds.
Cultivation of endophytic fungi inhabiting Abies balsamea using two techniques: a comparative study
(University of New Brunswick, 2018) Fitzherbert, Tyson; Gray, Christopher; Johnson, John
Two cultivation techniques: leaf segment cultivation and dilution-series cultivation, were compared for recovery of endophytes from needles of Abies balsamea collected in Saint John, New Brunswick, Canada. Endophytes were cultured on 2% malt extract agar and morphology of the endophytic growth was used to aid identification of distinct isolates. Endophytes were isolated from A. balsamea needles using the leaf segment cultivation method at a frequency of 13%, all replicates of two distinct isolates. Endophytes were isolated form eight of 25 prepared isolation plates for the dilution-series method. All endophytic growth from the dilution-series method was single-celled yeast species, while the endophytic growth from the leaf segment method was exclusively filamentous fungal species; thus, dichotomy was seen between the two methods of isolation.
Determination of a link between the taxonomic relationship of Canadian medicinal plants and the exhibited antibiotic activity of their crude extracts
(University of New Brunswick, 2019) Therrien, Julie K.; Gray, Christopher
Chemotaxonomy is effective in determining the expected chemical compounds found in extracts from different organisms. However, this is time-consuming and costly, as it is based on purified fractions of a chemical extract. Utilizing biological activity data of extracts and relating it to the taxonomic relationship of plants may be a more effective approach. The aim of this study was to determine if a link exists between the taxonomic relationship of plants and the exhibited antibiotic activity of their extracts. The antibiotic activity of methanolic extracts of 90 plants were evaluated against eight microorganisms. Bioactivity profiles were created and analyzed, using two separate methods. It was found that the lowest taxonomic level that correlated with the bioactivity profiles of the extracts was family.
Developing and testing a lab protocol to study the feeding ecology of American lobster (Homarus americanus) larvae
(University of New Brunswick, 2024-04) Power, Brooke-Lyn; Rochette, Rémy
Little is known about the natural feeding ecology of American lobster larvae. Through a lab experiment using different sizes of natural zooplankton, this study aims to develop a lab protocol to raise lobster larvae on a natural diet. Shortly after hatch, larvae were placed in individual containers and fed zooplankton collected from surface tows, with survival, inter-moult duration, and carapace length measured. This protocol showed promise, since it resulted in the complete development of some larvae, and it showed differences in survival rate and inter-moult period among larvae in the different zooplankton treatments. Development was sub-optimal when compared to a well-known lab study that raised lobster larvae from the same general region on an artificial diet, with lower survival and higher inter-moult duration for some or all stages. With improvements this protocol is expected allow raising lobster larvae on natural zooplankton to gain insight into their feeding ecology.
Developing Genomic Resources Towards Understanding the Influence of an Introgressed Inversion on Atlantic Bluefin Tuna’s Recovery.
(University of New Brunswick, 2025-03) Scher, Abigail K.; Dr. Rebekah A. Oomen
The influence of introgression on the recovery of depleted populations is currently an empirically understudied evolutionary process, despite its function in providing adaptive genetic variation which may favour adaptation and speciation. Atlantic bluefin tuna (Thunnus thynnus; hereafter, ABFT) exemplifies a unique case of introgression, where a chromosomal inversion was introduced into their population from another tuna species. Given that tuna have undergone a recent rapid demographic recovery from near extinction levels due to overexploitation, it is opportune to investigate the correlation between the inversion and ABFT’s recovery. Resources were developed for the target application of investigating the correlation. Tissue, DNA and high-quality sequence banks, spanning a decade, were created and assessed temporally, using low coverage whole genome sequencing for the sequence bank. DNA content decreased as storage duration increased; however, DNA quality remained stable. Additionally, a comparative genomic approach was employed to putatively locate the inversion on chromosome 24.
Does land-use affect bird abundance?
(University of New Brunswick, 2019) Prosser, Jacob; Houlahan, Jeff
Over the last 50 years many species have seen negative population trends and scientists have identified habitat loss, change, and fragmentation as possible causes. I investigated the ability of random forest and boosted trees models to predict bird abundances based on land-use throughout the United States. Bird abundance data was acquired from the North American Breed Bird Survey (BBS) and land-use data was gathered by the Multi-Resolution Land Characteristics (MRLC) consortium. The models had a mixed transferability between the training and test data with 14 of 21 models better fit the training data. The models were mixed in their ability to accurately predict abundances based on land-use compared to the mean; 14 of 21 models more accuracy predict abundance compared to the mean suggesting an effect of land-use on abundance. Six models were classified as “good,” 11 as “cautious,” and 4 as “poor.”

Browse

Browsing Honours Theses by Title

Results Per Page

Sort Options