HELCOM RED LIST Biotope Expert Team
bottoms in the photic zone 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 . Perennial attached algae cover at least
10 % of the seabed and more than other perennial attached erect groups.
Out of the perennial attached algae non-filamentous corticated red algae
constitute at least 50 % of the biovolume.
range: >4.5 psu; Exposure range: Sheltered; Depth range: photic zone to
about 10 meters
to the Quark in the north and central Gulf of Finland in the east
light penetration depth and increased sedimentation caused by eutrophication
2.4 Gravel bottoms
2.4.2 Sublittoral photic zone
220.127.116.11 Level bottoms dominated by macrophyte vegetation
A5 Sublittoral sediment
A5.5 Sublittoral macrophyte-dominated sediment
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