AB.J3 Baltic aphotic sand characterized by macroscopic infaunal biotic structures


Author                                     

HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic bottoms in the aphotic zone 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. Macroscopic infauna present, no epibenthic macrofauna.

Physical environment       

Salinity range: all; Exposure range: all; Depth range: below photic zone ‑ more common in deeper areas.

Characteristic species        

Mya arenaria, Macoma baltica, Arctica islandica, Pygospio elegans, Marenzelleria spp., Hediste diversicolor, Monoporeia affinis, Chironomidae

Mapping advise (habitat delineation, identification, similar types)             

Sandy bottoms in the aphotic zone with less than 20 % of mud/silt/clay fraction (<63 µm), and more than 70 % of sand (grain size 0.063–2 mm ). Macroscopic infauna present, no epibenthic macrofauna.      

Geographic range               

Whole Baltic Sea

Anthropogenic threats     

Sand excavation, silting caused by eutrophication, dredging spoil deposition etc.

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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