AB.E1F Baltic aphotic shell gravel characterized by epibenthic chordates


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic aphotic bottoms with at least 90 % coverage of shell gravel.Sessile/semi-sessile epibenthic chordates cover at least 10 %of the seabedand more than other perennial attached erect groups.

Physical environment       

Substrate is shell gravel. Depth below approximately 20 m. Appears mostly in high energy exposure areas.

Characteristic species        

Ciona intestinalis

Geographic range               

Southern part of Baltic Sea

Anthropogenic threats     

Increase in atmospheric CO2 (Ocean acidification)

Correspondence with other classification systems               

HELCOM 1998:

2.6 Shell gravel bottoms

2.6.1 Aphotic zone

HELCOM 2007:

Shell gravel bottoms

  • habitat under threat and/or in decline in all areas of occurrence: The Southern Baltic Proper, The Gulf of Gdansk, Bay of Mecklenburg, Kiel Bay, Little Belt, Great Belt, The Sound, Kattegat

 EUNIS 2012:

A5 Sublittoral sediment

A5.1 Sublittoral coarse sediment

A5.11 Infralittoral coarse sediment in low or reduced salinity

A5.115Baltic shell gravel bottoms of the aphotic zone