Floristic classification of opportunistic green macroalgae communities of the European myxomesohaline seas

Abstract

Shallow-water communities of opportunistic green marine macroalgae in eutrophicated areas are currently gaining an advantage over communities dominated by other groups of macrophytes. Therefore, their classification, study of composition and observation of structural changes are of particular importance. One class (Ulvae intestinalis–Ulvetea linzae), one order (Ulvae intestinalis–Ulvetalia linzae), three alliances (Ulvae intestinalis–Ulvion linzae, Ulvae intestinalis– Ceramion virgati, Ulvae rigidae–Gelidion spinosi) and three new associations of macroalgal communities of meso- and polysaprobic sublittoral vegetation within the shelf of the Black, Azov and Baltic Seas are described for the first time, using the Braun-Blanquet approach. Principal components analysis revealed two main factors influencing the floristic composition of the investigated communities: salinity and nutrient enrichment with associated turbidity. The proposed classification of opportunistic communities of green algae should be used in assessing the dynamics of the state of vegetation during eutrophication of the aquatic environment.