AA.M1S1 Baltic photic mixed substrate dominated by filamentous annual algae


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic bottoms in the photic zone with more than 10 %, but less than 90 % coverage of both hard and soft substrata. Annual algae cover at least 10 % of the seabed, while all other vegetation covers less than 10 %. Out of the annual algae, filamentous annual alagae constitute at least 50 % of the biovolume.

Physical environment       

Salinity range: all; Exposure range: all; Depth range: photic zone to about 0.5 meters.

Characteristic species        

Cladophora glomerata, Ceramium tenuicorne, Ulva spp., Pilayella littoralis, Dictyosiphon spp.


Must be mapped during the growth season.

Geographic range               

Whole Baltic Sea

Correspondence with other classification systems               

HELCOM 1998:

2.8 Mixed sediment bottoms

2.8.2 Sublittoral photic zone Dominated by macrophyte vegetation

EUNIS 2012:

A5 Sublittoral sediment

A5.5 Sublittoral macrophyte-dominated sediment