AA.I4 Baltic photic coarse sediment characterized by no macroscopic biotic structures


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. No macrovegetation, no macro- epi- or infauna.

Physical environment

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

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. No macrovegetation, no macro- epi- or infauna.

Geographic range

Whole Baltic Sea

Anthropogenic threats

Silting caused by eutrophication, dredging spoil deposition etc.

Correspondence with other classification systems

HELCOM 1998:

2.4 Gravel bottoms

2.4.2 Sublittoral photic zone Level bottoms with little or no macrophyte vegetation

EUNIS 2012:

A5 Sublittoral sediment

A5.1 Sublittoral coarse sediment

A5.11 Infralittoral coarse sediment in low or reduced salinity

A5.111 : Baltic level gravel bottoms of the infralittoral photic zone with little or no macrophyte vegetation