Skip to Main content Skip to Navigation
Master Thesis

Analyse statistique des facteurs environnementaux favorisant les efflorescences de cyanobactéries dans la retenue de Rophémel

Abstract : A bloom is defined as an exponential increase of the biomass of a given phytoplankton species in a water body, often linked to nutrients discharges caused by human activities. Harmful cyanobacterial blooms are a major threat for the structure of aquatic ecosystems and the production of drinkable water. In this study, we shed light on the occurrence of phytoplankton blooms in the reservoir of Rophémel, an eutrophic water body used to supply the city of Rennes (France) with drinking water. We analysed species counts of the phytoplankton community of the reservoir, and we studied records of various physical, chemical, hydrological and meteorological variables measured in and around the reservoir between 2006 ad 2016. Using different methods of analysis applied to multiple data tables (RDA, fourth-corner analysis), we set out to identify the variables most susceptible to favour bloom outbreaks. Most of the blooms recorded are caused by two cyanobacterial taxons, Microcystis and Planktothrix. We suspect that Arsenic levels in the reservoir might favor Microcystis against the rest of the community, even a low concentration. Using a functional traits-based approach, we highlighted the role of hydrodynamics and water temperature, in agreement with the literature on the subject. We recommend some modifications in the sampling of environmental variables to produce an efficient Machine Learning predictive model able to forecast efficiently bloom outbreaks in the reservoir.
Document type :
Master Thesis
Complete list of metadatas

Cited literature [68 references]  Display  Hide  Download

https://dumas.ccsd.cnrs.fr/dumas-01962978
Contributor : Agrocampus Ouest <>
Submitted on : Friday, December 21, 2018 - 8:53:10 AM
Last modification on : Monday, July 6, 2020 - 3:38:21 PM

File

2018_LeNoach_Philippe_DataScie...
Files produced by the author(s)

Identifiers

  • HAL Id : dumas-01962978, version 1

Collections

Citation

Philippe Le Noac'H. Analyse statistique des facteurs environnementaux favorisant les efflorescences de cyanobactéries dans la retenue de Rophémel. Sciences du Vivant [q-bio]. 2018. ⟨dumas-01962978⟩

Share

Metrics

Record views

51

Files downloads

131