Environmental Research Institute - Masters by Research Theses

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A drifter-based self-powered piezoelectric sensor for ocean wave measurements
(University College Cork, 2022-07-01) Kargar, Seyyed Masoud; Hao, Guangbo; Kavanagh, Richard; European Regional Development Fund
In the present research, a drifter-based piezoelectric sensor is proposed to measure ocean waves’ height and period. To analyze the motion principle and the working performance of the proposed drifter-based piezoelectric sensor, a dynamic model is developed. The developed dynamic model investigates the system’s response to an input of ocean waves and provides design insights into the geometrical and material parameters. Next, finite element analysis (FEA) simulations using the commercial software COMSOL-Multiphysics have been carried out with the help of a coupled physics analysis of Solid Mechanics and Electrostatics Modules to achieve the output voltages. An experimental prototype has been fabricated and tested to validate the results of the dynamic model and the FEA simulation. A slider-crank mechanism is used to mimic ocean waves throughout the experiment, and the results show a close match between the proposed dynamic modeling, FEA simulations, and experimental testing. In the end, a short discussion is devoted to interpreting the output results; comparing the results of the simulations and the experimental testing; the sensor’s resolution; and the self-powering functionality of the proposed drifter-based piezoelectric sensor.
Laboratory scale aerobic bioreactor conditioning of dairy processing wastewater as feedstock for Lemna minor production
(University College Cork, 2019) Broughton, Róisín; O'Leary, Niall
Dairy processing wastewater is a nutrient-rich resource, containing chemical oxygen demand (COD) ranging from 1,150 – 68,814 mg/L, nitrogen (N) from 14 – 1,462 mg/L and phosphorus (P) from 7.2 – 650 mg/L, depending on the product stream. This resource has potential to be utilised for cultivation of Lemna minor as a value-added product, in line with EU circular economy principles. The purpose of this project was to condition dairy processing wastewater for downstream application as growth media for Lemna minor. Effluent from both systems were tested for nutrient removal, and IASBR effluent was more suitable for the coupled system, with removal efficiencies of >90% COD, 4 – 94% NH4+ and 30 – 80% P respectively. The coupled system yielded poor nutrient removal and little to no plant growth, with plants reaching senescence by day 28 of the trial. It can be concluded that Lemna minor cultivation failed as a result of both A/O and IASBR operational issues (including starting pH) and insufficient seeding of cultivation tanks. It is therefore recommended to focus future studies on the suitability of anaerobic treatment technologies for conditioning of dairy processing wastewater for Lemna minor cultivation. Future work with coupled wastewater treatment/duckweed cultivation systems should also involve investigation into plant-symbiont interactions, as well as profiling of wastewater microbial communities and their potential impacts on duckweed growth.
Incorporating biotic interactions in phenology
(University College Cork, 2021-09-14) de la Torre Cerro, Rubén; Holloway, Paul; Cawkwell, Fiona; Environmental Protection Agency
Shifts in the timing of phenological events such as bird migration, leaf unfolding, flowering, and insect emergence, across many taxa and ecosystems are a result of climate change. Phenological shifts depend on different factors and species-specific sensitivity to changes in meteorological variables, therefore when phenological shifts occur within the trophic network we might expect phenological mismatches between interlinked species to occur as a result of climate change, with potential negative effects for biodiversity, ecosystems and the trophic network. However, the availability of data that show how species interactions are affected by climate change is scarce and unified criteria are still lacking on the methodologies studying phenology and biotic interactions. The presented extensive review on the topic allowed the identification of four broad categories of studies that have explored biotic interactions within phenology research and revealed that phenological studies of seasons other than spring are very scarce. This unbalance was also found within biotic interactions research, where mutualistic and obligate interactions, trophic interactions and networks were the main types receiving the most attention compared to other types (i.e., facilitation, competition). Researchers have commonly used co-existence among species as a proxy for biotic interactions, in many cases without any direct measurement of such interactions, while a lack of formal examination in most studies exploring phenological mismatches in response to climate change was also often identified. A conceptual framework was developed for the inclusion of phenology in the study of biotic interactions that categorises research into the conceptualisation and modelling of biotic interactions. Conceptualisation explores phenological data, types of interactions, and the spatiotemporal dimensions, which all determine the representation for biotic interactions within the modelling framework, and the type of models that are applicable. Emerging opportunities were also identified to investigate biotic interactions in phenology research, including spatially and temporally explicit species distribution models as proxies for phenological events and the combination of novel technologies (e.g., acoustic recorders, telemetry data) to quantify interactions. This conceptual framework was applied to a case of study in Ireland, investigating the relevance of different meteorological drivers (maximum and minimum temperature and total precipitation) in the phenology and co-existence of several species linked through the trophic network. Phenological trends towards an earlier phenology in Ireland were identified in terms of advanced date of arrival of migrant birds, first flight of butterflies and moths and green-up (start of the growing season) over the period 2008-2018. A novel analysis developed by van de Pol et al. (2016), the relative sliding time window analyses, was applied in order to identify which meteorological drivers had higher influence on the phenological events of study. Results showed high interannual variability in the time windows at species and group level. We identified common trends between butterflies and moths to show greater influence of temperature time windows when closer to first flight, while in vegetation the opposite pattern was found. Three new indices of phenological change across different trophic levels are presented, these indices allowed to identify potential phenological asynchronies between trophic levels in Ireland and to develop a network of potential interactions based on synchrony among interlinked species.
Aggregate potential of Irish south coast offshore palaeovalleys
(University College Cork, 2021-04-28) O'Mahony, Evan; Wheeler, Andrew; Lim, Aaron; Science Foundation Ireland; Petroleum Infrastructure Programme (PIP)
The southern shelf of offshore Ireland possesses many developed marine based resources such as hydrocarbons and commercial fisheries. Increasing knowledge of the seabed and the processes that cause large scale variation to the morphology and sedimentology is crucial in determining marine aggregate resource potential on the south coast. Qualitative data was processed using a multiproxy geophysical and sedimentological approach, creating detailed seabed maps using bathymetric data supported by ground truthing sedimentsamples. Surficial sediment deposits display a close fit to industry standard aggregates but considerable temporal variance at depth from vibrocore analysis shows variable marine reworking over time. Marine processes off the south coast diminish the aggregate quality of reworked fluvio-glacial deposits as evidence of increased marine reworking causes the replacement of favorable coarse-grained deposits with shell fragments. The southern shelf, at depth shows potential for marine aggregate exploration but variance within the extractable near surface deposits deems it too variable and accurate prediction of areas with high aggregate yield is diminished.
Plastic-free UCC: exploring societal and marketing levers
(University College Cork, 2020-12) Hughes, Aoife; Byrne, Edmond; O'Neill, Claire; Dunphy, Niall; Mullally, Gerard; Kirrane, Maria; University College Cork
Plastic pollution is a visible symbol of the increasingly urgent environmental issues facing our world. Single-use plastic packaging comprises about half of plastic waste produced, much of which is used briefly before disposal (UNEP 2018). Meanwhile only approximately 9% of all plastic generated by 2015 were recycled (Geyer et al. 2017). Such figures highlight an entrenched and unhealthy reliance on single-use plastic (SUP) within the current dominant social paradigm which promotes unsustainable levels of growth in consumption and disposal. This research examines how sustainable practices can be facilitated and supported within University College Cork to transition away from SUP. This was done using a mixed method approach of surveys and interviews to examine how stakeholders and community members navigated sustainable behaviour and what barriers they encountered. The research highlights the persistence of cost, availability of alternatives, personal preferences and unsustainable defaults as barriers to sustainable consumption. Infrastructure also influenced behaviour with a lack of supporting infrastructure limiting the adoption of sustainable alternatives. The attitude-behaviour gap also emerged as a barrier to behaviour change re-affirming the need for systemic change rather than relying on individuals to drive changes. The research shows the importance of those in leadership roles prioritising sustainability and the importance of sustainable champions to drive middle-out change in behaviours and policies. Finally, the research highlights the need for stakeholder involvement and collaboration to sustain sustainability initiatives and for their feedback to be used to adapt initiatives.

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