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Estimating the presence and diversity of microplastics in South African seagrass meadows
Thesis (MSc)--Stellenbosch University, 2024.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2025
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| _version_ | 1867614065834065920 |
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| access_status_str | Open Access |
| author | Boshoff, Bianca Jade |
| author2 | Von der Heyden, Sophie |
| author_browse | Boshoff, Bianca Jade Von der Heyden, Sophie |
| author_facet | Von der Heyden, Sophie Boshoff, Bianca Jade |
| author_sort | Boshoff, Bianca Jade |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/131587 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:07.073Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2025 |
| publishDateRange | 2025 |
| publishDateSort | 2025 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/131587 Estimating the presence and diversity of microplastics in South African seagrass meadows Boshoff, Bianca Jade Von der Heyden, Sophie Stellenbosch University. Faculty of Science. Dept. of Botany and Zoology. Seagrasses -- Ecology Microplastics Microplastics -- Environmental aspects -- South Africa Microplastics -- Health aspects Plastic marine debris Marine ecosystem management UCTD Thesis (MSc)--Stellenbosch University, 2024. ENGLISH ABSTRACT: Microplastics, plastic particles <5 mm in size, are a widespread phenomenon in marine ecosystems that threaten biota and human wellbeing. Seagrasses have been hypothesised to act as natural filters of microplastics due to their particle trapping abilities, yet little is known about the extent of microplastics within the sediment of seagrass beds. The aim of this study was to evaluate and compare microplastic accumulation in the sediments of Zostera capensis meadows with adjacent bare sediments in four South African estuaries. Sediment samples were collected from two locations containing Zostera capensis meadows in the middle reaches of each estuary and density flotation was used to separate microplastics from sediments. The mean number of microplastics ranged between 23.5 ± 24.9 and 30.1 ± 22.1 microplastics per Kg sediment, with up to 70% of all identified particles being fibre microplastics. In three of the four estuaries, significantly more microplastics were found in areas of dense seagrass coverage compared to areas of bare sediment (p<0.05), with fibres and fragments found to be the dominant microplastic type, while blue was revealed to be the dominant microplastic colour throughout the estuaries. This study confirmed the trapping ability of seagrass meadows for microplastics and highlights the need for research into the negative effects of microplastics on seagrass health. Furthermore, since accurately assessing microplastics in marine environments is challenging due to the lack of standardized protocols for sample collection and analysis, a review was conducted which compared methodologies from 36 studies on microplastics in sediment, water, and biota from South Africa's marine environments, including the sea, coastline, estuaries, and harbours. Sample collection methods varied with bulk sampling being most common for sediment while mesh nets and sieves were used for water, however, variations in the sample collection devices and mesh net pore sizes were observed between studies. Laboratory procedures consistently involved density separation, digestion, filtration, and microscope identification, but varied in specifics like separation solutions, digestion methods, and filter pore sizes. These variations could affect microplastic abundance estimates. Standardizing sampling methods and laboratory protocols is essential for accurate comparisons of microplastic levels across marine environments and for implementing effective management plans. AFRIKAANSE OPSOMMING: Mikroplastiek, plastiekdeeltjies <5 mm in grootte, is 'n wydverspreide verskynsel in mariene ekosisteme wat biota en menslike welstand bedreig. Dit word voorgestel dat seegrasse as natuurlike filtreerders van mikroplastiek kan optree weens hul vermoë om deeltjies vas te vang, maar min is bekend oor die omvang van mikroplastiek binne die sediment van seegrasbeddes. Die doel van hierdie studie was om mikroplastiekopbou in die sedimente van Zostera capensis-weivelde met aangrensende kaal sedimente in vier Suid-Afrikaanse riviermondings te evalueer en te vergelyk. Sedimentmonsters is versamel van twee plekke wat Zostera capensis-weivelde in die middelgedeeltes van elke riviermonding bevat, en digtheidsflotasie is gebruik om mikroplastiek van sedimente te skei. Die aantal mikroplastiek het gewissel tussen 23.5 ± 24.9 en 30.1 ± 22.1 mikroplastiek per kg sediment, met tot 70% van alle geïdentifiseerde deeltjies wat vesel-mikroplastiek was. In drie van die vier riviermondings is beduidend meer mikroplastiek gevind in areas met digte seegrasbedekking in vergelyking met kaal sediment (p<0.05), met vesels en fragmente wat die dominante mikroplastiektipe was, terwyl blou die dominante mikroplastiekkleur deur die riviermondings was. Hierdie studie het die vermoë van seegrasweivelde om mikroplastiek vas te vang, bevestig en beklemtoon die behoefte aan navorsing oor die negatiewe gevolge van mikroplastiek op seegrasse se gesondheid. Verder, aangesien dit moeilik is om mikroplastiek akkuraat in mariene omgewings te meet weens die gebrek aan gestandaardiseerde protokolle vir monsterinsameling en -ontleding, is 'n oorsig uitgevoer wat metodologieë van 36 studies oor mikroplastiek in sediment, water, en biota van Suid- Afrika se mariene omgewings vergelyk het, insluitend die see, kuslyn, riviermondings, en hawens. Monsterinsamelingsmetodes het gewissel met grootmaatmonsterneming wat die meeste algemeen vir sediment was, terwyl maasnette en sifte vir water gebruik is, maar verskille in die monsterversameltoestelle en maasnetporiegroottes is waargeneem tussen studies. Laboratoriumprosedures het konsekwent digtheidsskeiding, vertering, filtrasie en mikroskoopidentifikasie ingesluit, maar het verskil in spesifieke aspekte soos skeidingsoplossings, verteringsmetodes en filters se poriegroottes. Hierdie variasies kan mikroplastiek-opbrengsberamings beïnvloed. Die standaardisering van monsterinsamelingmetodes en laboratoriumprotokolle is noodsaaklik vir akkurate vergelykings van mikroplastiekvlakke oor mariene omgewings heen en vir die implementering van doeltreffende bestuurplanne. Masters 2025-01-28T10:10:37Z 2025-01-28T10:10:37Z 2024-12 Thesis https://scholar.sun.ac.za/handle/10019.1/131587 en Stellenbosch University xii, 99 pages : illustrations, maps application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Seagrasses -- Ecology Microplastics Microplastics -- Environmental aspects -- South Africa Microplastics -- Health aspects Plastic marine debris Marine ecosystem management UCTD Boshoff, Bianca Jade Estimating the presence and diversity of microplastics in South African seagrass meadows |
| title | Estimating the presence and diversity of microplastics in South African seagrass meadows |
| title_full | Estimating the presence and diversity of microplastics in South African seagrass meadows |
| title_fullStr | Estimating the presence and diversity of microplastics in South African seagrass meadows |
| title_full_unstemmed | Estimating the presence and diversity of microplastics in South African seagrass meadows |
| title_short | Estimating the presence and diversity of microplastics in South African seagrass meadows |
| title_sort | estimating the presence and diversity of microplastics in south african seagrass meadows |
| topic | Seagrasses -- Ecology Microplastics Microplastics -- Environmental aspects -- South Africa Microplastics -- Health aspects Plastic marine debris Marine ecosystem management UCTD |
| url | https://scholar.sun.ac.za/handle/10019.1/131587 |
| work_keys_str_mv | AT boshoffbiancajade estimatingthepresenceanddiversityofmicroplasticsinsouthafricanseagrassmeadows |