The invasion of toxic microalgae continues on Opal coast. Researchers from the French Research Institute for the Exploitation of the Sea (Ifremer) observed this during a new sampling campaign carried out over ten days in April between Ambleteuse (Pas-de-Calais), in the north, and Le Trport (Seine-Maritime), towards the south. Among their first analyses, they observed very significant concentrations Phaeocystis globosananoplankton algae that live in colonies and which it produces slime that makes the water viscous and causes foul-smelling moss to accumulate on the shore.
As Ifremer experts point out, a concentration of this microalgae of one million cells per liter is sufficient. disrupt the ecosystem, by removing the zooplankton that feeds the rest of the marine fauna and causes the accumulation of toxins in the shells. Gold, in the studied area, concentrations Phaeocystis it can easily reach 10 to 20 million cells per liter in certain years. And this time, but even closer to the coast than before.
We observed a particularly high abundance of this phytoplankton along the coast, with biomass five to ten times higher at the level of the Somme estuary or the Gulf of Authie compared to the open sea.confirms Alain Lefebvre, biologist and head of the Environment and Resources Laboratory at the Ifremer Boulogne-sur-Mer (Pas-de-Calais) research unit. This strong presence confirms our hypotheses about the role of nutrient input, via rivers, on proliferation Phaeocystis globosa and especially nitrate and phosphate residues from local agricultural and industrial activities. The final results of this observation campaign will be used for several ongoing research projects.
Article published on May 24, 2024