AA.H1Q Baltic photic muddy sediment characterized by stable aggregations of unattached perennial vegetation


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic bottoms in the photic zone with at least 90 % coverage of muddy sediment. The sediment must contain at least 20 % of mud, silt or clay (grain size less than 63 ┬Ám). Stable aggregations of unattached perennial vegetation cover at least 10 % of the seabed, while perennial attached erect groups  cover less than 10 %.

Physical environment       

Substrate is muddy sediment. Salinity range: all; Exposure range: sheltered; Depth range: photic zone

Characteristic species        

Fucus vesiculosus normal and dwarf form, Furcellaria lumbricalis, Ceratophyllum demersumm

Geographic range              

Whole Baltic Sea

Anthropogenic threats     


Correspondence with other classification systems               

HELCOM 1998:
2.7 Muddy bottoms

2.7.2 Sublittoral photic zone Dominated by macrophyte vegetation

EUNIS 2012:

A5 Sublittoral sediment

A5.5 Sublittoral macrophyte-dominated sediment