Diversity and structure of epibenthic communities across subtidal artificial hard habitats in the Bay of Cherbourg (English Channel).

To inform the performance of ecological engineering designs for artificial structures at sea, it is essential to characterise their impacts on the epibenthic communities colonising them. In this context, the present study aims to compare the community structure among natural and four different artificial hard habitats with different ages and features installed in the Bay of Cherbourg (English Channel): ) cinder blocks and ) boulders, both installed six years prior to the study, and ) smooth and ) rugous concrete dykes, both installed one year prior to this study. Results showed that artificial habitats installed six years ago harboured communities with functional and taxonomic diversity characteristic of mature communities but were still different from those of natural habitat.

Influence of nutrient enrichment on colonisation and photosynthetic parameters of hard substrate marine microphytobenthos.

This study aimed to assess the influence of nutrient enrichment on the development of microalgal biofilm on concrete and PVC cubes. Three mesocosms were utilized to create a nutrient gradient over a period of 28 days. Various parameters including biomass, photosynthetic activity, microtopography, and extracellular polymeric substances (EPS) were measured.

Colonisation of artificial structures by primary producers: competition and photosynthetic behaviour.

Colonisation of artificial structures by primary producers is an important determinant for eco-engineering projects. In this context, interactions between the colonisation by microphytobenthic biofilm and macroalgae were explored on 48 samples of marine infrastructures (MI) immersed for one year in the English Channel. Marine infrastructures samples with smooth and rough surface were compared to evaluate the influence of surface micro-scale rugosity.

Coupling high frequency monitoring and bioassay experiments to investigate a harmful algal bloom in the Bay of Seine (French-English Channel).

Coastal ecosystems are increasingly threatened by eutrophication and dystrophy. In this context, the full pattern of a bloom dominated by the dinoflagellate, Lepidodinium chlorophorum, was investigated by a high frequency monitoring buoy equipped with sensors allowing nutrients and photosynthesis measurements. An increase of the N/P ratio affected phytoplankton physiology leading to bloom collapse with a slight oxygen depletion.