AA.I1B4 Baltic photic coarse sediment dominated by Charales


Author                                     

HELCOM RED LIST Biotope Expert Team

Textual description            

Baltic bottoms in the photic zone with at least 90 % coverage of coarse sediment. Coarse sediment has less than 20 % of mud/silt/clay fraction (<63 µm), and the proportion of gravel and pebbles (grain size 2–63 mm) exceeds 30% of the combined gravel and sand fraction . Submerged rooted plants cover at least 10 % of the seabed and more than other perennial attached erect groups. Of the submerged rooted plants, Charales constitutes at least 50 % of the biovolume.

Physical environment       

Salinity range: <6 psu; Exposure range: Sheltered to moderately exposed; Depth range: photic zone from about 0.2 to 7 meters.

Characteristic species        

Chara aspera, Chara baltica Tolypella nidifica, Chara horrida

GEOGRAPHIC RANGE

Whole Baltic Sea

Anthropogenic threats   

Eutrophication

Correspondence with other classification systems               

HELCOM 1998:

2.4 Gravel bottoms

2.4.2 Sublittoral photic zone

2.4.2.2 Level bottoms dominated by macrophyte vegetation

EUNIS 2012:

A5 Sublittoral sediment

A5.5 Sublittoral macrophyte-dominated sediment

http://eunis.eea.europa.eu/habitats/1733


 related information

This biotope has been listed as Near Threatened (NT) in the HELCOM Red List of Baltic Sea biotopes and habitats.

See the Biotope Information Sheet of AA.I1B4

 Publications

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