Environmental Research Institute - Masters by Research Theses

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    Primary and secondary emissions from upland fires in Ireland
    (University College Cork, 2023-04-26) Felberbauer, Clara; Hellebust, Stig; Venables, Dean; Environmental Protection Agency; Horizon 2020
    Emissions from wildfires have detrimental effects on air quality, climate change and human health. Despite frequent occurrence of wildfires and prescribed agricultural burns in upland areas, data on wildfire emissions in Ireland is scarce. This work was conducted as part of FLARES (Fire, Land and Atmospheric Remote Sensing of EmissionS), a project funded by the Irish Environmental Protection Agency (EPA) to improve the understanding of Irish upland fire emissions. Emission factors (EF) of typical Irish wildfire fuels (heather, gorse, purple moor grass) were measured for the first time. Emission factors were measured for a set of gases (carbon monoxide CO, carbon dioxide CO2, methane CH4, sulphur dioxide SO2 and nitric oxides NOx as NO), particulates and particulate fractions (fine particulate matter PM2.5, total particulate matter TPM, black carbon BC, organic carbon OC, elemental carbon EC and total carbon TC) and molecular biomarkers (levoglucosan, mannosan, galactosan, 4-Nitrocatechol 4-NC, 4-Nitrophenol 4-NP and 4-Nitroguaiacol 4-NG). Emission factors of measured gases were as follows: CO: 42 g/kg (heather), 27 g/kg (moor grass) and 80 g/kg (gorse); CO2 1167 g/kg (heather), 1558 g/kg (moor grass) and 1442 g/kg (gorse); SO2: 1.38 g/kg (heather), 1.08 g/kg (moor grass) and 1.68 g/kg g/kg (gorse); NOx as NO: 4.46 g/kg (heather), 5.51 g/kg (moor grass), and 6.85 g/kg (moor grass); CH4: 0.21 g/kg (moor grass) and 0.38 g/kg (gorse). Particulate EFs resulted in EF of 4.71 g/kg (heather), 2.42 g/kg (moor grass) and 10.46 g/kg (gorse) for PM2.5; 3.95 g/kg (heather), 4.26 g/kg (moor grass) and 14.33 g/kg (gorse) for TPM; 0.26 g/kg (heather), 0.21 g/kg (moor grass) and 0.50 g/kg (gorse) for BC; 1.28 g/kg (heather), 1.26 g/kg (moor grass) and 5.43 g/kg (gorse) for OC; 0.80 g/kg (heather), 0.81 g/kg (moor grass) and 2.23 g/kg (gorse) for EC; 2.09 g/kg (heather), 2.07 g/kg (moor grass) and 7.65 g/kg g/kg (gorse) for TC. EFs for biomarkers were 0.09 g/kg (heather), 0.18 g/kg (moor grass) and 0.19 g/kg (gorse) for levoglucosan; 0.01 g/kg (heather), 0.01 g/kg (moor grass) and 0.01 g/kg (gorse) for mannosan and 0.01 g/kg (heather), 0.01 g/kg (moor grass) and 0.02 g/kg (gorse) for galactosan; 0.78 mg/kg (heather), 0.42 mg/kg (moor grass) and 1.36 mg/kg (gorse) for 4-NC; 0.05 mg/kg (heather), 0.04 mg/kg (moor grass) and 0.07 mg/kg (gorse) for 4-NP and 0.25 mg/kg (heather), 0.15 mg/kg (moor grass) and 0.34 mg/kg (gorse) for 4-NG. Combustion took place under flaming combustion conditions, reflected in high modified combustion efficiencies (MCE) of 0.95 to 0.98. Emissions for species like CO, PM2.5 and volatile organic compounds (VOCs) would be expected to be higher under real-world conditions where MCE is lower. Secondary organic aerosol (SOA) formation from combustion emissions of the three fuels was studied under simulated day-time (UV lights and UV+OH precursor addition) and night-time conditions (dark + O3 addition) in an atmospheric simulation chamber. SOA mass increased by 2-11% and was dependent on fuel type and oxidising conditions. Field and laboratory samples were analysed at the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, Germany. Filter samples were analysed for the biomarkers levoglucosan, mannosan, galactosan, 4-nitrocatechol, 4-nitrophenol, and 4-nitroguiacol. Laboratory experiments were complemented by field studies. Ambient levels of PM2.5 and BC were measured during an 8-week field study in Glencree, rural Co. Wicklow, Ireland. Source appointment of BC and analysis of biomarkers found no unambiguous signals that could be associated with wildfires. However, this dataset represents a valuable glance at air quality in a rural setting in Ireland. Despite the remote location and low population density in Glencree Valley, anthropogenic influences on air quality were significant, most notably from residential solid fuel burning. Monthly PM2.5 concentrations in Glencree (4.6 μg m–3) were lower than in nearby urban Tallaght (7.0 μg m–3), but less than expected based on the difference in population and local pollution sources. Other field observations included opportunistic sampling of the plume of a major wildfire at Killarney National Park, Co. Kerry, in April 2022. Findings presented in this thesis contribute to the understanding of wildfire emissions in Ireland and highlight the influence of anthropogenic air pollution from solid fuel burning on rural locations.
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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.
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    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.
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    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.
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    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.