**3.1** *Phaeophyceae* **(or Fucophyceae)**

There are about 2000 species (in 265 genera) of brown algae [22], and less than 1% are known from freshwaters (3–7 genera) [23]. The brown color is due to Fucoxanthin (carotenoid pigment) and in some species to the presence of tannins (phenolic compounds).
