AA.H1B3 Baltic photic muddy sediment dominated by watermilfoil (Myriophyllum spicatum and/or Myriophyllum sibiricum)


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). Submerged rooted plants cover at least 10 % of the seabed and more than other perennial attached erect groups. Of the submerged rooted plants, watermilfoil constitutes at least 50 % of the biovolume

Physical environment       

Salinity range: <6 psu; Exposure range: low; Depth range: photic zone from about 0.2 to 2 meters.

Characteristic species        

Myriophyllum spicatum, Myriophyllum sibiricum

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

A5.54 Angiosperm communities in reduced salinity