AA.I Baltic photic coarse sediment


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. 

Physical environment

Salinity range: all; Exposure range: moderate to high; Depth range: photic zone

Characteristic species

Phanerogams, charales, mobile epifauna, infauna

Mapping advise (habitat delineation, identification, similar types)

Photic zone areas with coarse sediment such as gravel. Sediment must contain less than 20 % of silt, clay or mud, and at least 30 % of grain size 2–63 mm.

Geographic range

Whole Baltic Sea

Anthropogenic threats

Decreased light penetration depth caused by eutrophication, dredging, extraction mining

Correspondence with other classification systems

HELCOM 1998:

2.4 Gravel bottoms

2.4.2 Sublittoral photic zone

 EUNIS 2012:

A5 Sublittoral sediment

A5.1 Sublittoral coarse sediment