AA.H3O Baltic photic muddy sediment characterized by infaunal echinoderms


HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic photic 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). No macrovegetation or epibenthic macrofauna. Biomass of infaunal echinoderms dominates in the group infaunal bivalves/polychaetes/crustaceans/echinoderms/insect larvae.

Physical environment       

Substrate is muddy sediment. Appears in all energy exposure classes. Salinity relatively high (above approximately 10-15)

Characteristic species        

Amphiura spp, Ophiura spp, Brissopsis lyrifera, Echinocardium spp

Quality descriptors             

Diversity, abundance and biomass of fauna.

Geographic range               

Kattegatt, the Sound

Anthropogenic threats     

Eutrophication, contaminants

Correspondence with other classification systems               

HELCOM 1998:
2.7 Muddy bottoms

2.7.2 Sublittoral photic zone With little or no macrophyte vegetation

EUNIS 2012:

A5 Sublittoral sediment

A5.3 Sublittoral mud

A5.31 Sublittoral mud in low or reduced salinity

A5.311 Baltic brackish water sublittoral muddy biocenoses influenced by varying salinity