The fate and impacts of microplastics in marine systems

Microplastic pollution prevails in marine habitats globally and is now regarded as one of the leading threats to marine biodiversity. Despite the recent increase in microplastic studies, there are a number of key areas that remain largely understudied. Furthering our knowledge of where and why microplastics accumulate is crucial for prioritising conservation efforts. There also remains a dearth of knowledge surrounding the impacts of microplastics on marine taxa, and particularly on ecosystem dynamics. The overall aim of this thesis is to investigate the presence of microplastics in marine systems and highlight their impacts on marine taxa. In this thesis, I highlight the abundances of microplastics globally through a meta-analysis of published literature, and demonstrate that laboratory microplastics studies utilise values that far exceed those found in the environment. In addition, this study also showed that there is incomparability among microplastics studies in the literature, particularly in terms of units of measurement. Through an analysis of benthic sediment samples, I demonstrate that high levels of microplastics are present in Antarctic deep-sea regions, and in an economically important fishing ground in the Irish Sea. I also show that novel functional response analyses can be used to determine the impacts of microplastic pollution on predator-prey interactions and ecosystems dynamics. Finally, I highlight that microplastics can affect the mechanisms in which marine animals such as hermit crabs compete for resources. The data and results presented in this thesis provides valuable information on the accumulation of microplastics globally, and their effects on ecosystem functionality and key survival behaviours. Given that microplastics are a complex pollutant, this thesis encourages new studies to be more comparable and highlights the challenges of aiming for environmental relevance when conducting laboratory-based studies. These suggestions will help to increase our understanding of marine microplastic pollution in a more unified way.

Name dc:type.qualificationname

Doctor of Philosophy

Level dc:type.qualificationlevel

Doctoral Thesis

Grantor dc:publisher.institution

Queen's University Belfast

Year dc:date.issued

2022

Author dc:creator

• Cunningham, Mánus

Advisor dc:contributor.advisor

• Dick, Jaimie

• Microplastics
• marine
• pollution
• crustaceans
• bivalves
• decapod
• animal behaviour
• plastics

Language dc:language

eng

Identifier

oai:pure.qub.ac.uk/portal:studenttheses/742935d6-05f3-40ef-88b2-62e9c5476955

OAI identifier oai:identifier

oai:pure.qub.ac.uk/portal:studenttheses/742935d6-05f3-40ef-88b2-62e9c5476955