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oai:figshare.com:article/32826119 2026-10-01T16:10:36Z portal_1172 item_type_8 month_year_10_2026

Microplastics in terrestrial ecosystems and their effects on macroinvertebrates Alix McDaid (20395928) PUREID: 659407190 microplastics terrestrial environment earthworms proteomics behaviour behaviour change animal behaviour marine biology coastal ecology terrestrial ecology marine ecology Microplastic (MP) pollution is a global environmental concern, yet its impacts on terrestrial and marine ecosystems remain poorly understood. This thesis investigates the presence and biological effects of MPs across agricultural soils and marine environments, with a particular focus on Northern Ireland. A regional survey provided the first comprehensive assessment of MPs in Northern Irish agricultural soils, revealing concentrations significantly lower than global averages, with rayon fibres and polyethylene fragments the most common types. Sources were linked to historical textile activity and agricultural practices, underscoring the need for improved waste management and mitigation strategies. Experimental studies examined the effects of low-density polyethylene (LDPE) and rayon on earthworm species Lumbricus terrestris and Eisenia fetida. Unexpectedly, worms often preferred MP-contaminated soils, while exposure influenced risk-taking behaviour, escape responses, and weight in some treatments. At the physiological level, MP exposure altered antioxidant enzyme expression, suggesting stress-related responses with potential consequences for soil health. The research was extended to marine systems using the European hermit crab, Pagurus bernhardus. Microplastic exposure influenced shell selection behaviour in a sex-dependent manner, altering motivation, decision-making, and responses to predatory threat. These findings highlight behavioural disruptions that may affect survival and fitness in marine invertebrates. Collectively, this thesis advances understanding of MPs by combining field surveys with behavioural and physiological experiments across terrestrial and marine ecosystems. It demonstrates that responses to MPs are species- and context-dependent, encompassing both behavioural and molecular pathways. The findings underscore the urgent need for comprehensive risk assessments, stakeholder awareness, and sustainable alternatives to reduce MP pollution and safeguard soil health, biodiversity, and ecosystem services. Thesis is embargoed until 31 December 2028. 2026-10-01T16:10:36Z Text Thesis 10.17034/32826119.v1 https://figshare.com/articles/thesis/Microplastics_in_terrestrial_ecosystems_and_their_effects_on_macroinvertebrates/32826119 All Rights Reserved Open Access after 2028-12-31