AThe algae have been studies by Burrows and Farnham (1980) and Burrows (1981); some 150 species have been identified. Their occurrence and distribution are mainly determined by salinity and available substrates. Some of these species have been rarely recorded; the stonewort Lamprothamnium papulosum is known from only three other brackish sites in the British Isles [now known to occur at more sites than this] but had been found in the Fleet since 1869. Alien seaweeds have also been discovered, namely Grateloupia filicina var. luxurians, Solieria chordalis and recently, Sargassum muticum. The latter two species occur within Weymouth Bay and have migrated into the Fleet on mobile substrates such as stones and shells. In the deeper channels (2-5m) of East Fleet many interesting sublittoral algae occur, including Acrothrix gracilis, Cordylecladia erecta, Gloisiphonia capillaris and Gracilaria (all three British species). Other algae grow as epiphytes on Zostera leaves, e.g. Cladosiphon zosterae or entangled around the bases e.g. Entermorpha flexuosa and Cladophora spp. Ulva usually forms massive growths in West Fleet, especially during the summer, perhaps in response to eutrophication.

Next Section