Vincent Iratçabal
Doctorant Paléoclimatologie
Dynamics and temporal evolution of toxic algal blooms from coastal Brittany sediments
Supervisors
David Menier
Clément Lambert
Aurélie Penaud
Abstract
The Brittany littoral is a district of strong economic attractiveness. On the other hand, the coastal environment is experiencing growing vulnerability facing the climate change and global environmental challenges. Under the combined effects of anthropogenic and demographic pressure on the littoral and basins, as well as hydroclimatic hazards, the littoral is undergoing significant transformation. Between all the clues of the current mutation, we encounter an increasing frequency of episodes of Harmful Algal Blooms (HABs). This occurrence has a significant impact on the entire territory and has serious repercussions on conchology activities. If the short-term dynamic of this kind of episode is beginning to gain a better understanding thanks to monitoring networks, the long-term tendency allowing predictions is still missing. To address this issue, our project targets the retrospective analysis of Harmful Algal Blooms (HABs) through the study of littoral sedimentary archives in Brittany estuaries and bays. The main objective is to characterize the evolution of toxic phytoplankton communities (migration, species relay, etc.) over the past centuries. The monitoring network established at the end of the 20th century lacks a "step back" in time to represent the evolution of communities and efflorescence dynamics outside of an anthropic context. Paleoecological studies will be combined with other multidisciplinary methods through collaboration (ancient DNA, geochemistry, other bioindicators, remote sensing), allowing us to discuss the global evolution of water mass and coastal ecosystem quality. Moreover, it aims to document critical factors in the triggering of past Harmful Algal Blooms (HABs) to gain a deeper understanding of current efflorescence. This work is an essential prerequisite to improve the prediction and management capacities of modern HABs.
