Phylum: Cyanobacteria Family: Nostocaceae
Trichormus variabilis (Kützing ex Bornet & Flahault) Komárek & Anagnostidis, 1989
A common species that can be found in freshwater as well as marine
References:
John, Whitton & Brook (2011) - The Freshwater Algal Flora of the British Isles