AB.I4U Baltic aphotic coarse sediment characterized by no macrocommunity


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic aphotic bottoms with at least 90 % coverage of coarse sediment. Coarse sediment has less than 20 % of mud/silt/clay fraction (<63 µm), and the proportion of gravel and pebbles (grain size 2–63 mm) exceeds 30% of the combined gravel and sand fraction . Macro- epi- or infauna is not present.

Physical environment       

Substrate is coarse sediment. Depth below approximately 30 m. Appears in high energy exposure areas.

Geographic range               

Whole Baltic Sea

Correspondence with other classification systems               

HELCOM 1998:
2.4 Gravel bottoms

2.4.1 Aphotic zone

EUNIS 2012:

A5 Sublittoral sediment

A5.1 Sublittoral coarse sediment

A5.11 Infralittoral coarse sediment in low or reduced salinity

A5.114 : Baltic gravel bottoms of the aphotic zone