The Northern Adriatic Sea
Moderately polluted site
Calothrix crustacea
Rivularia spec.
Ulothrix spec.
Gelidium pusillum
Blidingia minima
Enteromorpha spec.
Ulva rigid a
Scytosiphon lomentaria
Enteromorpha spec.
with Ulva rigida
HWL
LWL
crustose corallines
........
::.,
H'~~,
381
Fig. 16.5. Scheme of zonation pattern at a moderately polluted site; HWL high water
level; L WL low water level
spp., Microcoleus chtonoplastes, Calothrix crustacea, Lithoderma
adriaticum and Oscillatoria spp.). In the eulittoral, the Fucus virsoides
and/or Cystoseira compressa associations deteriorated. They were
replaced by seasonal annuals, mainly by green algae belonging to the
genera Blidingia, Enteromorpha, Cladophora and Uiva. Perennial turflike mats of Gelidium pusillum with interwoven Gelidiella species and
Laurencia papillosa occupied rocky surfaces in the lower eulittoral. During spring, seasonal species, which could form the understorey of Fucus
virsoides stands in undisturbed sites, occupied eulittoral slopes in distinct zones: Bangia a tropurp urea, Ulothrix species, Blidingia minima,
Porphyra leucosticta (in patches), Enteromorpha intestinalis, dwarf Ulva
rigida and lowermost Scytosiphon lomentaria.