Download Baltic photic sand dominated by stable

Red List of European Habitats
Habitat code & name
AA.J1Q - Baltic photic sand characterized by stable aggregations of unattached
perennial vegetation
Author and Date
HELCOM RED LIST Biotope Expert Team, November 2013.
Relationship to EUNIS
The biotope does not correspond directly to any EUNIS (2004) level 4 habitats due to
structural differences the classification systems. The closest correspondence in EUNIS is to
subhabitats of ‘Sublittoral macrophyte-dominated sediment’ (A5.5).
Habitat description
Baltic bottoms in the photic 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. Stable aggregations of
unattached perennial vegetation covers at least 10%, while perennial attached erect
groups cover less than 10% of the bottom. The biotope is rare, but can be found in most
of the Baltic Sea area where the salinity is <10 or 5 psu (depending on the area), the
exposure is moderate to sheltered and the seabed is level over wide areas within the
photic zone.
Three sub-biotopes with different dominant species of vegetation can be identified.
‘Baltic photic sand dominated by stable aggregations of unattached Fucus spp. (typical
form)’ (AA.J1Q1) can be identified where the biovolume of Fucus spp. (typical form)
constitutes at least 50% of the biovolume. This sub-biotope is encountered down to a
depth of 5 meters.
‘Baltic photic sand dominated by stable aggregations of unattached Fucus spp. (dwarf
form)’ (AA.J1Q2) can be identified where the biovolume of a specific morphological
dwarf form of Fucus spp. constitutes at least 50% of the total biovolume of the
unattached perennial vegetation. This sub-habitat is the only one of the five sub-habitats
which has been classified as endangered (EN; A1) in the HELCOM Red List Assessment in
2013. This specific morphology of the Fucus spp. dwarf form lacks bladders and holdfasts;
it is regularly dichotomous branched with branches of similar length resulting in a fanshaped appearance of the thalli. The single plants can be loosely anchored in the
sediment with its lower, dark brownish parts. The thalli are very fragile, break very easily
into pieces and thus generate new thalli (Bauch 1954). Under more exposed conditions
plants form a ball-shaped form, able to roll over the sea bottom (Bauch 1954). The Fucus
dwarf forms coexist with attached F. vesiculosus, unattached Furcellaria lumbricalis,
higher plants like Ruppia spp., Zannichellia palustris, Stukenia pectinatus, Zostera spp. and
several charophytes. The biotope exists in lower mesohaline salinities (7–10 psu) and
moderately exposed to very sheltered conditions. It forms a characteristic biotope of
shallow bays and lagoons between 0.25 and 2.5 m (Overbeck 1965). The unattached
thalli can cover the sediment up to about 10 cm height and thus form a threedimensional habitat comparable to the interstitial space in coarse sediments. Epifauna is
seldom attached to the Fucus dwarf form, but in between the loose lying thalli mobile
gastropods, amphipods and insects look for shelter and food (von Oertzen 1968).
However, if abundances of the unattached form are very high, the sediment below
becomes deoxygenated and the associated infauna below the Fucus layer may die.
Presently this biotope is only known to occur in Sweden and Germany. In Germany it
exists only in very few coastal lagoons with low to moderate eutrophication pressures and
salinities of around 7–10 psu.
‘Baltic photic sand dominated by stable aggregations of unattached Furcellaria
lumbricalis’ (AA.J1Q3) can be identified where the biovolume of Furcellaria lumbricalis
constitutes at least 50% of the biovolume. This sub-biotope is encountered down to a
depth of 10 meters.
Characteristic species
Fucus spp., Furcellaria lumbricalis
Indicators of quality
Depending on the sub-habitat:
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‘Baltic photic muddy sediment dominated by stable aggregations of unattached
Fucus spp. (typical form)’ (AA.H1Q1): density of unattached Fucus spp. (normal
form).
‘Baltic photic muddy sediment dominated by stable aggregations of unattached
Fucus spp. (dwarf form)’ (AA.H1Q2): density of unattached Fucus spp. (dwarf
form).
‘Baltic photic muddy sediment dominated by stable aggregations of unattached
Furcellaria lumbricalis’ (AA.H1Q3): Lower limit of Furcellaria belt, amount of
epiphytic algae, and density of Furcellaria.
Relationships with other schemes
Annex 1 relationships
The relationship between HUB biotopes and Annex 1 habitats has not yet been mapped
by HELCOM.
MAES relationships
Marine - Marine inlets and transitional waters
Marine - Coastal
MSFD relationships
Shallow sublittoral sand
EUSeaMap relationships
Shallow sands
IUCN ecosystem relationships
9.4 Sublittoral Sandy
Other relationships
Level 5 of the HELCOM HUB classification (2013). This habitat has three sub-habitats on
HUB level 6;
‘Baltic photic sand dominated by stable aggregations of unattached Fucus spp. (typical
form)’ (AA.J1Q1)
‘Baltic photic sand dominated by stable aggregations of unattached Fucus spp. (dwarf
form)’ (AA.J1Q2)
‘Baltic photic sand dominated by stable aggregations of unattached Furcellaria
lumbricalis’ (AA.J1Q3)
Photograph
Please see the end of the document for a picture on the sub-habitat ‘Baltic photic sand
dominated by stable aggregations of unattached Fucus spp. (dwarf form)’ (AA.J1Q2).
Countries list
To be inserted when data sheets completed.
Regional Sea
Baltic Sea
Baltic Proper
Belt Sea
Gulf of Bothnia
Gulf of Finland
Gulf of Riga
The Sound
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Map
This will be inserted by NatureBureau based on the Regional Sea information above.
References
HELCOM Website 1 http://helcom.fi/baltic-sea-trends/biodiversity/helcom-hub/hub/aa-j1q
HELCOM website 2
http://helcom.fi/Red%20List%20of%20biotopes%20habitats%20and%20biotope%20complexe/HELCOM%
20Red%20List%20AA.M1Q2,%20AA.H1Q2.%20AA.J1Q2,%20AA.J1Q2.pdf
Unattached ball-shaped Fucus dwarf form on sandy substrate (left) and fan-shaped of different size on sandy
bottom (right) (Photo: Karin Fürhaupter, MariLim GmbH)