E-Thesis 4 views
Unravelling the Seagrass Microbiome / PHILIP ELLWOOD
Swansea University Author: PHILIP ELLWOOD
Abstract
Seagrass meadows are marine angiosperms critically important for carbon sequestration and fauna nursery grounds. The global decline of seagrass habitats is associated with coastal nutrient pollution.The seagrass microbiome influences plant health under changing environmental conditions. The response...
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Swansea University
2026
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| Institution: | Swansea University |
| Degree level: | Master of Research |
| Degree name: | MRes |
| Supervisor: | Sonnenschein, E. C., and Greco, C. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa71503 |
| Abstract: |
Seagrass meadows are marine angiosperms critically important for carbon sequestration and fauna nursery grounds. The global decline of seagrass habitats is associated with coastal nutrient pollution.The seagrass microbiome influences plant health under changing environmental conditions. The response of microbial interactions to nutrient overload are poorly understood. This study used a novel high throughput workflow to map interactions within the seagrass microbiome and evaluate the effect of nutrients on these interactions. Twelve bacterial strains isolated from seagrass seeds were used, creating pairwise co-cultures using robot-assisted colony printing. These bacterial co-cultures were grown and monitored on control and nutrient-enriched media (nitrate, phosphate, iron and copper)using automated imaging and image analysis. Use of these novel technologies both in bacterial pinning and growth monitoring, allowed detection of pronounced differences in growth with mono-cultures of Lysobacter luteus S6 reaching a colony size of 12 mm2 whereas Psychromonas arctica S11 showed minimal growth reaching 4 mm2. Across nutrient addition treatments the microbial growth and co-culture interactions showed dramatic shifts with multiple strains being inhibited while other strains developed mutualisms to combat the nutrient stress. For example, Pseudoalteromonas spiralis S5 when paired with Rhodococcus cerasti S3 in high phosphate concentrations showed 827.9 ±14.3 mm larger growth whereas Rhodococcus cerasti S3 showed the highest growth curves with Pseudoalteromonas spiralis S5 than it did with any other condition. Additionally, four fungal species were isolated and identified in this research by extraction from seagrass meadows. These including endophytes (Pyrenochaetopsis leptospora, Pseudeurotium zonatum) potentially contributing to blade health and epiphytes (Penicillium commune, Cladosporium halotolerans) linked to root-associated defence. This research demonstrates high throughput technologies can successfully be used for large scale microbial interactions cross-examinations to understand partnerships and ideal growth conditions. These could be utilised towards probiotic-based approaches to improve seagrass health, germination and resilience to anthropogenic stress. |
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| Keywords: |
Seagrass, Microbiome, Microbial ecology |
| College: |
Faculty of Science and Engineering |