AA.H1Q5 Baltic muddy sediment dominated by stable unattached aggregations of lake ball (Aegagropila linnaei)


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 µm). No perennial attached erect group has a coverage ≥ 10%. Stable aggregations of unattached perennial vegetation cover at least 10 % of the seabed. Out of the unattached perennial vegetation Aegagropila linnaei constitutes at least 50 % of the biovolume.

Physical environment       

Salinity range: <5 psu; Exposure range: sheltered; Depth range: photic zone to about 5 meters.

Characteristic species        

Aegagropila linnaei

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