Connectivity of marine populations

Type: 
Master Thesis subject (30 ECTS)
programme: 
EMBC+
For many decades the prevailing notion was that ocean currents facilitate long distance dispersal of propagules, resulting in panmictic populations. In contrast, recent DNA-based studies using sequences or microsatellites revealed strong genetic differentiation on small geographic scales, supporting that vicariance and isolation of populations play a major role in shaping marine biodiversity. Effective conservation and management efforts need a profound understanding of ecological processes that are fundamental for the resilience of marine ecosystems (e.g. coral reefs). Resilience is the ability of ecosystems to absorb shocks, resist phase-shifts, and regenerate after human-induced or natural disturbances. An important key element in resilience is the successful larval re-colonisation after disturbance events. Therefore, the degree of connectivity, which can be estimated by analysing gene flow, is crucial to understand re-colonisation and to plan conservation and management efforts. Connectivity is “the demographic linking of local populations through the dispersal among them of individuals as larvae, juveniles, or adults“. High connectivity will promote resilience and recovery from large-scale disturbances. This is especially important in the context of the spatial arrangement of marine protected areas (MPAs) that are considered an important tool to prevent overexploitation and ensure the sustainable use of living marine resources. It is proposed that MPAs should be arranged in a network and that the spatial distribution should match the dispersal capabilities of the species to be protected. In a thesis project, connectivity will be investigated by the application of genetic markers to infer gene flow among populations of marine fauna. Such genetic markers are mitochondrial DNA (mtDNA) sequences and microsatellites. Tissue samples of various animal species (e.g. anemonefish, giant clams, sea squirts, and starfish) from Indo-Pacific coral reefs are available in the Marine Biology Laboratory and lab work will be carried out at the VUB. Additional sampling during fieldwork in the tropics might be possible for MSc students, but has to be financed by a scholarship (e.g. VLIR). Data analysis will be conducted with state-of-the-art bioinformatics tools in order to infer gene flow as a proxy for connectivity. The results will be discussed in a marine ecological context, because the focus of such a thesis project is on the ecological aspect of connectivity and not genetics itself. Molecular genetic methods are used as a tool for marine ecological research. More information about this subject can be obtained from the following publications, which can be requested from me: Huyghe F, Kochzius M (2016) Highly restricted gene flow between disjunct populations of the skunk clownfish (Amphiprion akallopisos) in the Indian Ocean. Marine Ecology - An Evolutionary Perspective doi: 10.1111/maec.12357 Hui M, Nuryanto A, Kochzius M (2016) Concordance of microsatellite and mitochondrial DNA markers in detecting genetic population structure in the boring giant clam, Tridacna crocea, across the Indo-Malay Archipelago. Marine Ecology - An Evolutionary Perspective doi: 10.1111/maec.12389 van der Ven RM, Triest L, De Ryck DJR, Mwaura JM, Mohammed MS, Kochzius M (2015) Population genetic structure of the stony coral Acropora tenuis shows high but variable connectivity in East Africa. Journal of Biogeography DOI: 10.1111/jbi.12643 Alcazar DSR, Kochzius M (2015) Genetic population structure of the blue sea star Linckia laevigata in the Visayas (Philippines). Journal of the Marine Biological Association of the United Kingdom, doi:10.1017/S0025315415000971 Dohna TA, Timm J, Hamid L, Kochzius M (2015) Limited connectivity and a phylogeographic break characterize populations of the pink anemonefish, Amphiprion perideraion, in the Indo-Malay Archipelago: inferences from a mitochondrial and microsatellite loci. Ecology and Evolution doi: 10.1002/ece3.1455 Madduppa HH, Timm J, Kochzius M (2014) Interspecific, spatial and temporal variability of self-recruitment in anemonefishes. PLoS ONE 9(2): e90648. doi:10.1371/journal.pone.0090648 Timm J, Planes S, Kochzius M (2012) High similarity of genetic population structure in the False Clown Anemonefish (Amphiprion ocellaris) found in microsatellite and mitochondrial control region analysis. Conservation Genetics 13: 693-706
prerequisites: 
Depending on the topic.
Number of students: 
1
academic year: 
2016-2017
Contact person email: 
contact person first name: 
Marc
contact person last name: 
Kochzius
Institutes Involved: 
Reference Number: RP-48221