Spatio-temporal dynamics of Pseudo-nitzschia australis bloom in the Iroise Sea: A multi-disciplinary study combining gene expression, environment and hydrodynamics
Prigent, L. (2023). Spatio-temporal dynamics of Pseudo-nitzschia australis bloom in the Iroise Sea: A multi-disciplinary study combining gene expression, environment and hydrodynamics. PhD Thesis. Université de Bretagne Occidentale: Bretagne. 347 pp.
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Document type: Dissertation
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| Keywords |
Hydrodynamics
Pseudo-nitzschia australis Frenguelli, 1939 [WoRMS]
ANE, France, Brittany, Iroise Sea [Marine Regions]
Marine/Coastal |
| Author keywords |
spatio-temporal bloom, metatranscriptomics |
| Abstract |
Diatoms of the Pseudo-nitzschia genus produce domoic acid, a neurotoxin responsible for amnesic poisoning syndrome in humans, following consumption of filter-feeding mollusks, andmortality in mammals and seabirds. In France, West-Finistère is regularly affected in early spring by one of the most toxic species, P. australis. This thesis focuses on the spatio-temporal dynamics of blooms of this species in the Iroise Sea. By combining hydrodynamic simulations, metatranscriptomics, monitoring of blooms and associated environmental conditions, this thesis has highlighted the important role of hydrodynamics in the initiation and extension of P. australis blooms (and other diatom species). Hydrodynamic transport of the blooms from south to north has been identified, with potential development in the Bay of Douarnenez before being transported further north to the Bay of Brest. This local development in the Bay ofDouarnenez could be favoured by low dilution, allowing cells to accumulate. However, no relationship between the local environment and the spatio-temporal shift in the blooms could beestablished. However, it was discovered that sexual reproduction plays an essential role in the physiology of P. australis during an in situ bloom. This study highlights the combined roleof the environment, hydrodynamic connectivity and the life cycle in the development, transport and persistence of a bloom in a natural environment. |
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