2nd International BIOSPHERES Symposium

TCGRNG participates to this conference under numerical form. A poster was accepted by the organization, under a short version with an audio presentation of 5 minutes. A large version was also edited, link of both are available at the bottom of this page. The documents are available in English and French.

Accepted abstract

Assessment of the physical impact of the pelagic algae of genus Sargassum on the coastal area of Guadeloupe and Martinique

Jean-François, M. Dorville1 et Claude Cayol1

1The Caribbean Geophysical and Numerical Research Group

Baie-Mahault, Guadeloupe

jf.dorville@tcgnrg.com, cl.cayol@gmail.com

Since 2010, the observed beaching of pelagic algae of genus Sargassum is increasing, reaching a pick during 2018. The species S. fluitans and S. natans because of their mobility, can be found in a large tropical band in the North and South Atlantic ocean.

These algae equipped with floats are advected by the surface marine current and wind. At the passage of an emerged land or boat wake, they can be met in the vicinity of the coast and then be pushed toward the coastlines (beaches, limestone plateau, rip-rap) by oceanic wave and tide action.

The modifications of the environment of those living organisms, hot and shallow water, act on their growth and reproduction dynamics. These changes impact the physical features of the algae from its buoyancy to its composition, going through by its rigidity and its roughness.

This add of organic matter in a sensitive area, and mostly urbanised, has effects that local politicians qualify as cataclysmic for the biosphere.

This study inventories mechanical, thermic and chemical effects of the presence of brown algae on the costs of Guadeloupe et Martinique. Based on two years of field observations and numerical modelling of the sea state, effects of the presence of algae are classified and their potential impact on the biodiversity are assessed.

Keywords : sargassum, mechanic, thermal effect, field observation, modelling, pollution, biodiversity

Short version of the poster with five (5) minutes of audio description

English version of the poster presented at the Biosphere 2 Online Conference (Schoelcher, Martinique) December 2020

Video of introduction of the Biosphere 2 Online Conference