Date of Defense
30-10-2025 12:00 PM
Location
F1-2022
Document Type
Thesis Defense
Degree Name
Master of Science in Environmental Sciences and Sustainability
College
COS
Department
Biology
First Advisor
Dr. Amit Kumar
Keywords
Microplastics, polypropylene, polyethylene terephthalate, adipic acid, sequential and synchronized treatment.
Abstract
Microplastic (MP) pollution poses a growing threat to global ecosystems, particularly in coastal habitats like mangroves, which serve as vital carbon sinks. This study investigates the specific impacts of polypropylene (PP), polyethylene terephthalate (PET), and adipic acid (AA) on microbial community assembly in mangrove sediments, with a focus on sequential arrival of different MPs. Based on MP identity, early arrival of specific MP before others can significantly impact microbial community composition and their functioning. However, the impacts of the sequential arrival of MPs on microbial communities have never been studied. This research fills this important knowledge gap by using novel sequential and synchronized addition of MPs on prokaryotic communities in mangrove sediments. The rationale is to inform coastal management in regions like the UAE, where urban development exacerbates MP pollution, threatening ecosystem resilience. Methods involved collecting mangrove sediments from Abu Dhabi, establishing microcosms with six treatments (PP-first, PET-first, AA-first, synchronized-early, synchronized-late, and control), incubating for six weeks, and analyzing microbial communities via 16S rRNA sequencing. The specific analytical measures examined included alpha and beta diversity metrics, ordination techniques such as NMDS and PCA, taxonomic heatmaps, and flower diagrams. Results of the study revealed different perspectives, the first one being that exposure to microplastics tends to reduce alpha diversity by 15-24% and generally causes lower beta diversity. Additionally, microplastics exposure caused communities to shift toward generalists like Gammaproteobacteria while decreasing specialists like Desulfobacterota, and occasionally microbial restructuring was induced by the sequential arrival of different MPs. Moreover, the exposure caused microbiome functions to reorient from biosynthesis domination to stress response mechanisms, implying reduced ecosystem multifunctionality .
Included in
INVESTIGATING THE IMPACTS OF MICROPLASTICS ON BACTERIAL COMMUNITY DYNAMICS IN MANGROVE SEDIMENTS
F1-2022
Microplastic (MP) pollution poses a growing threat to global ecosystems, particularly in coastal habitats like mangroves, which serve as vital carbon sinks. This study investigates the specific impacts of polypropylene (PP), polyethylene terephthalate (PET), and adipic acid (AA) on microbial community assembly in mangrove sediments, with a focus on sequential arrival of different MPs. Based on MP identity, early arrival of specific MP before others can significantly impact microbial community composition and their functioning. However, the impacts of the sequential arrival of MPs on microbial communities have never been studied. This research fills this important knowledge gap by using novel sequential and synchronized addition of MPs on prokaryotic communities in mangrove sediments. The rationale is to inform coastal management in regions like the UAE, where urban development exacerbates MP pollution, threatening ecosystem resilience. Methods involved collecting mangrove sediments from Abu Dhabi, establishing microcosms with six treatments (PP-first, PET-first, AA-first, synchronized-early, synchronized-late, and control), incubating for six weeks, and analyzing microbial communities via 16S rRNA sequencing. The specific analytical measures examined included alpha and beta diversity metrics, ordination techniques such as NMDS and PCA, taxonomic heatmaps, and flower diagrams. Results of the study revealed different perspectives, the first one being that exposure to microplastics tends to reduce alpha diversity by 15-24% and generally causes lower beta diversity. Additionally, microplastics exposure caused communities to shift toward generalists like Gammaproteobacteria while decreasing specialists like Desulfobacterota, and occasionally microbial restructuring was induced by the sequential arrival of different MPs. Moreover, the exposure caused microbiome functions to reorient from biosynthesis domination to stress response mechanisms, implying reduced ecosystem multifunctionality .