Skip to Main content Skip to Navigation
Theses

Effet des variations climatiques sur la production de Matière Organique Algale et Microcystines par le phytoplancton dans les systèmes eutrophes. Etude de leur élimination dans le procédé de traitement des eaux

Abstract : Eutrophication phenomena are characterized by phytoplankton proliferation and as a consequence negatively impacts aquatic ecosystem and natural water uses. During its development, phytoplankton produces Algal Organic Matter (AOM) which increases the organic content of the water resource and modifies the Natural Organic Matter (NOM) characteristics and reactivity. When toxic cyanobacteria are present, cyanotoxins can be produced. The future climate, predicted by experts, will support these proliferations and promote their consequences. The optimization of a HPLC-UV/PDA method to identify and quantify extracellular Microcystins (MCs) after SPE decreased the quantification limit to 0,1 μg/L. However, a basic pH and the OM content of the sample over-estimated the concentration. Under variable temperature and rainfall conditions, the cells growth and the AOM and MCs production were studied on laboratory cultures of mono-specific species of algae and cyanobacteria. The cellular growth, the concentration and proportion of hydrophobic fractions of AOM, the total concentration of MCs and the proportion of extracellular MCs were impacted by climate changes. An in-situ monitoring program was conducted during 21 months on the hypertrophic Pigeard pond (87) and the results were compared to the 18 months monitoring of 2012-2013. Recurrent inputs of AOM annually and sustainably disturbed NOM dynamics and modified its characteristics by increasing the OM content and the hydrophilic proportion. The observed evolutions in water resources under various climates (Sweden and Togo) confirmed the laboratory observations. These quantitative and qualitative NOM changes also affect the efficiency of water treatment processes and especially adsorption on PAC. The efficiency was reduced in the presence of hydrophilic fraction and high MCs adsorption yields were observed for MCs despite a competition with OM.
Document type :
Theses
Complete list of metadatas

Cited literature [301 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02467907
Contributor : Abes Star :  Contact
Submitted on : Wednesday, February 5, 2020 - 12:39:08 PM
Last modification on : Friday, March 13, 2020 - 11:46:07 AM
Long-term archiving on: : Wednesday, May 6, 2020 - 3:47:55 PM

File

2019LIMO0093.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02467907, version 1

Collections

Citation

Hélène Thuret-Benoist. Effet des variations climatiques sur la production de Matière Organique Algale et Microcystines par le phytoplancton dans les systèmes eutrophes. Etude de leur élimination dans le procédé de traitement des eaux. Sciences de la Terre. Université de Limoges, 2019. Français. ⟨NNT : 2019LIMO0093⟩. ⟨tel-02467907⟩

Share

Metrics

Record views

298

Files downloads

181