PhD thesis of Carolyne Chercham

2021-2025

Predicting seagrass regional dynamics under climate change and human pressure using a hybrid modelling strategy

 

We aim to develop an innovative modelling framework to simulate seagrass growth and  bio-physical interactions in seagrass ecosystems

Intertidal seagrasses such as Zostera noltei are exposed to both the aquatic and the aerial environment. That means that they need to be able to resist various environmental stressors, such as currents, waves, heat, desiccation, cold etc. to survive and thrive.

In France, one of the largest Zostera noltei meadows is located in Arcachon Bay. It used to cover 70km² back in 1989, but declined to 40km² in 2019. Changes in the environment due to climatic and anthropogenic impacts are suspected to have initiated the decline.

In order to better understand and predict these changes in regional seagrass dynamics in Arcachon Bay, we develop an innovative hybrid model, that reproduces bio-physical feedbacks between the seagrass and its environment. This model two-way couples a deterministic model for the hydrodynamics and sediment dynamics with a probabilistic model for the seagrass growth. It allows us to investigate the spatio-temporal patterns of seagrass growth and health under the impact of various processes.

This project aims to demonstrate the feasibility and the advantages of this type of hybrid model for research and management purposes. Applications for other case studies are planned in the future.

Encadrants :

Héloïse Muller (DHYSED), Martin Marzloff (LEBCO), Paul WU (QUT), Romaric Verney (DHYSED)

Collaborations 

Queensland University of Technology (QUT, Australie)

Financement : 

DS-IFREMER