AB.H3L3 Baltic aphotic muddy sediment dominated by ocean quahog (Arctica islandica)


Author                                     

HELCOM RED LIST Biotope Expert Team

Textual description 

Baltic aphotic zone bottoms 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). 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, Ocean quahog (Arctica islandica) constitutes at least 50 % of the biomass.

Physical environment       

Substrate is muddy sediment. Appears in low to moderate energy exposure classes.

Characteristic species        

Arctica islandica

Quality descriptors

Diversity, abundance and biomass of fauna

GEOGRAPHIC RANGE

Western Baltic Sea

ANTHROPOGENIC THREATS

Eutrophication

Correspondence with other classification systems               

HELCOM 1998:

2.7 Muddy bottoms

2.7.1 Aphotic zone

EUNIS 2012:

A5 Sublittoral sediment

A5.3 Sublittoral mud

A5.37 Deep circalittoral mud

A5.378 Baltic muddy bottoms of the aphotic zone

http://eunis.eea.europa.eu/habitats/2588

 RELATED INFORMATION

This biotope has been listed as Critically Endangered (CR​​) in the HELCOM Red List of Baltic Sea biotopes and habitats.

See the Biotope Information Sheet of AB.H3L3

 Publications

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