HELCOM RED LIST Biotope Expert Team
Baltic photic 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. Less than 10 % of the seabed is covered by perennial vegetation or attached epifauna. Microphytobenthic organisms and grazing snails dominates. Grazing snails (e.g. Hydrobiidae, Theodoxus, Bithynia, Radix) constitute 50 % in biomass or volume
Substrate is muddy sediment. Most common in low salinity
Hydrobiidae, Theodoxus spp, Bithynia spp, Radix spp.
Diversity, abundance and biomass of fauna.
2.4 Gravel bottoms
2.4.2 Sublittoral photic zone
18.104.22.168 Level bottoms with little or no macrophyte vegetation
A5 Sublittoral sediment
A5.1 Sublittoral coarse sediment
A5.11 Infralittoral coarse sediment in low or reduced salinity
A5.111 : Baltic level gravel bottoms of the infralittoral photic zone with little or no macrophyte vegetation
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