AB.J3P1 Baltic aphotic sand dominated by midge larvae (Chironomidae)


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. Biomass of infaunal insect larvae dominates and is highest in the group that includes infaunal bivalves/polychaetes/crustaceans/echinoderms/insect larvae. Out of the infaunal insect larvae, Midge larvae (Chironomidae) constitutes at least 50% of the biomass.

PHYSICAL ENVIRONMENT

Substrate is sand. Appears in all wave exposure classes

Characteristic species        

Chironomidae

Quality descriptors

Diversity, abundance and biomass of fauna

ANTHROPOGENIC THREATS

Eutrophication

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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