Monitoring deep-sea benthic biodiversity using environmental DNA approaches to compare trawled and untrawled sites

dc.contributor.advisorVon der Heyden, Sophieen_ZA
dc.contributor.advisorSeymour, Maten_ZA
dc.contributor.authorOosthuizen, Deleneen_ZA
dc.contributor.otherStellenbosch University. Faculty of Science. Dept. of Botany and Zoology.en_ZA
dc.date.accessioned2021-11-26T05:29:09Z
dc.date.accessioned2021-12-22T14:24:20Z
dc.date.available2021-11-26T05:29:09Z
dc.date.available2021-12-22T14:24:20Z
dc.date.issued2021-12
dc.descriptionThesis (MSc)--Stellenbosch University, 2021.en_ZA
dc.description.abstractENGLISH ABSTRACT: The deep-sea is the largest environment on earth and yet it remains understudied. Environmental DNA (eDNA) metabarcoding provides a cost and time effective method to characterise and study deep-sea benthic communities. This study is the first study in South Africa to use eDNA to study benthic communities in the deep-sea. Sediment samples were collected from 29 sites on Childs Bank off the West Coast of South Africa. Certain sites had been closed to trawling for 5 years while others had been left open to trawling. DNA was extracted from the sediment samples and used to determine the taxonomic composition of the benthic communities. When compared to existing species inventories from the area, it was found that the eDNA metabarcoding recovered similar numbers of taxa, some of which were not listed in other species lists. However, many taxa could only be assigned to higher taxonomic levels such as order as many species are not represented in barcode databases. Environmental data such as site depth and sediment type and composition were also collected from the study sites. Community composition was then compared between sites to determine whether trawling, depth or sediment type affected community composition. Contrary to what was expected, depth was the only factor with a significant effect on community composition.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Die diepsee is die grootste habitat op aarde maar is steeds tot ‘n groot mate nog min bestudeer. Omgewings DNS-kodering bied ‘n tyd en koste effektiewe manier om diepsee organismes te ondersoek. Hierdie studie is die eerste van sy soort in Suid-Afrika om oDNS te gebruik om bentiese gemeenskappe in en op die diepsee bodem te bestudeer. Sediment monsters is van 29 data versamelpunte op Childs Bank langs die Weskus geneem. Dele van die area is gesluit vir treilvisserye terwyl ander dele oopgelos is. DNS is van die sediment monsters geïsoleer en gebruik om die taksonomiese samestelling van bentiese gemeenskappe te identifiseer. In vergelyking met ander spesie opnames van die area, het die studie soortgelyke getalle taksa gevind, waarvan sommige nie op die ander lyste teenwoordig was nie. ‘n Gedeelte van die taksa kon nie tot laer taksonomiese vlakke geïdentifiseer word nie omdat baie van hierdie spesies nie in DNS-kodering databasisse teenwoordig is nie. Ander inligting uit die omgewing (nl. diepte en sediment-tipe) is ook versamel. Die bentiese gemeenskap samestellings tussen areas kon vergelyk word om te bepaal of diepte, sediment- tipe of blootstelling aan treilvissery ‘n invloed op die samestelling van gemeenskappe het. In teenstelling met verwagtings, het net diepte ‘n noemenswaardige effek op bentiese gemeenskap samestellings getoon.af_ZA
dc.description.versionMastersen_ZA
dc.format.extent83 pages : mapsen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/123838
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subjectDeep-sea -- Ecologyen_ZA
dc.subjectBenthic community ecologyen_ZA
dc.subjectBenthic animals -- Effect of habitat modification on -- South Africa -- West Coasten_ZA
dc.subjectDeep-sea animals -- Effect of environment onen_ZA
dc.subjectEnvironmental DNAen_ZA
dc.subjectUCTDen_ZA
dc.titleMonitoring deep-sea benthic biodiversity using environmental DNA approaches to compare trawled and untrawled sitesen_ZA
dc.typeThesisen_ZA
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