AB.J1E1 Baltic aphotic sand dominated by Mytilidae


Author                                     

HELCOM RED LIST Biotope Expert Team

Textual description 

Baltic aphotic zone bottoms with at least 90 % coverage of sand.  Sand has less than 20 % of mud/silt/clay fraction (<63 µm), and the proportion of sand (grain size 0.063–2 mm) exceeds 70% of the combined gravel and sand fraction.  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.

Physical environment       

Substrate is sand. Appears in moderate to high energy exposure areas. Salinity must be at least 5.

Characteristic species        

Mytilus spp., Hediste diversicolor

Quality descriptors

Diversity, abundance and biomass of fauna.

Correspondence with other classification systems               

HELCOM 1998:

2.5 Sandy bottoms

2.5.1 Aphotic zone

EUNIS 2012:

A5 Sublittoral sediment

A5.2 Sublittoral sand

A5.27 Deep circalittoral sand

A5.273 Baltic sandy bottoms of the aphotic zone

http://eunis.eea.europa.eu/habitats/2620

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