Underwater photography from the bottom of "channel Esplanade" (or "Old Deul" or "Medium-Deule") in late winter in the part lined with a double ripisilve, upstream of the discharge of clean water pump Ledoux in Lille in northern France. The picture shows an abundance of filamentous algae, bacteria and microalgae, dead leaves not yet decomposed, some waste and many microparticles (including paper and plastic)