HELCOM RED LIST Biotope Expert Team
bottoms in the aphotic 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). Epibenthic bivalves cover at least 10% of the seabed and
more than other perennial attached erect groups. Out of the epibenthic
bivalves, Mytilidae constitutes at least 50 % of the biomass.
is muddy sediment. Appears in low to moderate energy exposure classes. Salinity
Mytilus spp., Hediste diversicolor, Gammarus spp.
abundance and biomass of fauna.
2.7 Muddy bottoms
2.7.1 Aphotic zone
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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