This work set out to study the population dynamics of jellyfish in European seas, employing population genetics and plankton surveys on a diverse range of gelatinous zooplankton. The European population of P. noctiluca was found to ba genetically unstructured. Within-aggregation inbreeding was detected suggestive of a reproductive role of aggregations in this species. A vestigial divergence into two clades was detected from the mitochondrial data. Gene flow is sufficient that these two clades are not geographically structured, or supported by nuclear markers. The results of the study of R. octopus population genetics were indicative of recent population expansion, probably during post-glacial colonisation of the current distribution. Populations of R. octopus are somewhat separated both geographically and genetically, indicating low gene flow between populations and high site fidelity The population genetics of jellyfish species may be closely linked with their biology. Meroplanktonic, metagenic species such as R. octopus have a more constrained niche due to their benthic life stages, and also may persist as asexually reproducing benthic colonies between years. These species are likely to have differentiated or differentiating populations, even when the motility of the species suggests high gene flow potential. Plankton sampling Is an effective method to study ephyral release as a proxy for strobilation. In Aurelia aurlta, the current findings contrast with published literature, where the consensus Is that strobilation initiates with rising temperatures. This study records ephyrae nine weeks prior to, and 2°C greater than, the thermal minimum, Increasing temperatures cannot be solely responsible for triggering strobilation. The wider gelatinous zooplankton community in Strangford Lough was found to be diverse, 33 taxa were recorded over 38 weeks. A census of the gelatinous zooplankton population was produced. The study examines the contribution of gelatinous species’ biology and ecology on population dynamics.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:706676 |
| Date | January 2016 |
| Creators | Glynn, Fergal |
| Publisher | Queen's University Belfast |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
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