HELCOM RED LIST Biotope Expert Team
Baltic aphotic bottoms 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). Sessile/semi-sessile epibenthic macrofauna is not present. Biomass of infaunal echinoderms dominates and is the highest in the group that includes infaunal bivalves/polychaetes/crustaceans/echinoderms/insect larvae.
Substrate is muddy sediment. Depth below approximately 20 m. Appears in all energy exposure classes.
Amphiura spp, Ophiura spp, Brissopsis lyrifera, Echinocardium spp
Diversity, abundance and biomass of fauna.
Whole Baltic Sea
HELCOM 1998: 2.7 Muddy bottoms
A5 Sublittoral sediment
A5.3 Sublittoral mud
A5.37 Deep circalittoral mud
A5.378 Baltic muddy bottoms of the aphotic zone
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HELCOM HUB: Technical Report on the HELCOM Underwater Biotope and habitat classification BSEP 139