HELCOM RED LIST Biotope Expert Team
Baltic aphotic zone 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 . Biomass of infaunal bivalves dominates and is highest in the group that includes infaunal bivalves/polychaetes/crustaceans/echinoderms/insect larvae. Out of the infaunal bivalves, multiple infaunal bivalve species (Macoma calcarea, Mya truncata, Astarte spp., Spisula spp) constitute at least 50 % of the biomass.
Macoma calcarea, Mya truncata, Astarte spp., Spisula spp
abundance and biomass of fauna
from German waters in the Baltic Sea
2.4 Gravel bottoms
2.4.1 Aphotic zone
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
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This biotope has been listed as Near Threatened (NT) in the HELCOM Red List of Baltic Sea biotopes and habitats.