Data/hora: 02/06/2024 12:34:07

Provedor de dados: | 5
País: | France
Título: | Etude des processus hydrodynamiques et écophysiologiques de la dynamique d'une algue invasive : Valonia aegagropila (C. Agardh) dans la lagune de Salses-Leucate
Autores: | Cesmat, Ludovic.
Data: | 2006-12-11
Ano: | 2006
Palavras-chave: | Model of alga growth; Invasive alga; Model of  Droop; Intern quota model; Hydrodynamic model; Invasive specie; Écophysiology; Population dynamic; Lagoon of Salses Leucate; Green alga; Valonia aegagropila; Modèle à quota interne; Modèle hydrodynamique; Espèce invasive; Écophysiologie; Algue verte; Dynamique des populations; Lagune de Salses Leucate; Valonia aegagropila.
Resumo: | Since 1980, the expansion of a green macro-alga: Valonia aegagropila (C Agardh) is observed in Salses-Leucate lagoon (France). It is currently distributed in the north of the lagoon with important biomasses (40 gDW/m²) eroding the cover of  Zostera noltii. The free form of the alga can be transported with the surface or bottom currents depending on seasons. It multiplies mainly by vegetative reproduction. There are few studies on the ecophysiological capacities of V. aegagropila. This work tries to answer why (physiological adaptation) and how (mechanical process of transport) the alga invaded the lagoon, with an approach including observations, experiments in controlled environment and biological and hydrodynamic models. The growth capacities depend on temperature and light intensities, the nutrients absorption rates and internal nitrogen and phosphorus internal quotas were measured and modelled using a Droop model based on internal quota. Vertically transport was studied with laboratory experiments and measurements of biomass transport were made into the lagoon. The biological model (growth, vertical transport, mortality) was coupled to the MARS 3D hydrodynamic model with a meshgrid of 160m. The results show an adaptation of the alga to low availability of phosphorus and an annual growth of biomass controlled by the availability of nutrient during winter. The alga seems to occupy the whole zones where growth is optimal and the risk of invasion of the southern part of the lagoon is limited. This work opens on research prospects on an ecological model (confronting physiological capacities and competition of V. aegagropila, Zostera noltii, green algae and primary production), new physiological experiments, ecological observations and potential valorisation of V. aegagropila.
Tipo: | Text
Idioma: | Francês
Identificador: | http://archimer.ifremer.fr/doc/2006/these-2453.pdf
Editor: | Universite Montpellier II
Relação: | http://archimer.ifremer.fr/doc/00000/2453/
Formato: | application/pdf