Chlorophyta (green algae)
  
A large division Chlorophyta units unicellular, colonial, coenobial, multicellular and coenocytic (siphonial) organisms which live in fresh waters reservoirs, soil and sea. Marine green algae include about 1000 species representing a little part of the division. Boreal- Arctic marine Chlorophyta are mainly multicellular forms. Only a few unicellular species are known and there anr no colonial forms. Chlorophill prevail in pigment composition and couse green colour of the algae.

Being related to fresh water algae, the marine green algae prefer the localities influenced by the river runoff, inhabiting shallow waters and freshened areas at the coast, fjords, lagoons and estuaries, which easly endure the organic pollution.
On the Spitsbergen coast, thin filiform small-sized forms with short life cycle (the seasonal and ephemeral forms) predominate among green algae. These life forms can sustain the environment conditions of Arctic littoral, so green algae used to be the main component of the vegetation in the tidal zone, forming sparde out associations with low biomass.
Species found in Hornsund