AB.H3L Baltic aphotic muddy sediment characterized by infaunal bivalves


Author                                     

HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic aphotic 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 ┬Ám). Sessile/semi-sessile epibenthic macrofaunais not present.Biomass of infaunal bivalves dominates and is highest in the group that includes infaunal bivalves/polychaetes/crustaceans/echinoderms/insect larvae.

Physical environment       

Substrate is muddy sediment. Depth below approximately 20 m. Appears in allenergy exposure classes.

Characteristic species        

Macoma balthica, Arctica islandica, Astarte spp.

Quality descriptors             

Diversity, abundance and biomass of fauna.

Geographic range               

Whole Baltic Sea

Anthropogenic threats     

Eutrophication, contaminants

Correspondence with other classification systems               

HELCOM 1998:
2.7 Muddy bottoms

2.7.1Aphotic 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