The Distribution and Abundance of Microplastics in Beach Sediment in the South Pacific, Oceania, and the Gulf of Mexico

The pervasive presence of microplastics in marine environments poses a significant natural resources management challenge. These pollutants are now detected in nearly all environments investigated, yet geographically broad studies remain limited, and the lack of standardized sampling and analytical practices continues to constrain global comparability. This study examines multicontinental trends in the occurrence of microplastics in marine beach sediments and evaluates the methodological challenges that impede large-scale investigations. Using Accelerated Solvent Extraction coupled with Pyrolysis-Gas Chromatography/Mass Spectrometry (ASE-Py-GCMS/MS) analysis, this study quantified regional microplastic concentrations in beach sands across the South Pacific, Oceania, and the Gulf of Mexico. Microplastics were detected at 95% of the 85 sites analyzed, confirming their presence in nearly all sampled regions--including many with no prior empirical data. Statistically significant differences occurred between eastern and western Australia and between eastern Australia and eastern New Zealand, reflecting regional variation in sources and hydrodynamic conditions. Polyethylene (PE) and polyethylene terephthalate (PET) were the dominant polymers identified, and sea state showed strong positive correlations with PE and nylon (N-66), highlighting the influence of wave energy on polymer accumulation. By characterizing spatial trends and valuating analytical constraints, this work contributes to the broader understanding of microplastic pollution in coastal environments. These findings establish a foundation for long-term monitoring, highlight factors influencing regional variation, and identify considerations to guide monitoring, management, and mitigation efforts addressing microplastic pollution and its implications for marine ecosystems and human health.

Name thesis:degree_name

Master of Marine Resources Management

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Marine Resources Management

Grantor

Texas A&M University

Year dc:date.issued

2025

Author dc:creator

• Cole, Russell Lee

Advisor dc:contributor.advisor

• Kaiser, Karl

Committee members dc:contributor.committeemember

• Ross, Ashley,
• Hala, David

• Biology, Oceanography

Language dc:language.iso

English

Handle dc:identifier.uri

https://hdl.handle.net/1969.1/1600737

OAI record oai:identifier

https://oaktrust.library.tamu.edu/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Aoaktrust.library.tamu.edu%3A1969.1%2F1600737