370
I.M. Munda
During the last few years, the benthic algal vegetation of the Adriatic
Sea has changed most probably because of severe pollution impact.
Especially in the shallow shelf area of the northern Adriatic, conditions
become locally critical, leading towards eutrophication and anoxia
(Degobbis et al. 1979; Degobbis 1989; Justic 1987; Stefanon and Boldrin
1982; Faganeli et al. 1985). This part of the Adriatic Sea receives a heavy
load of domestic wastes and industrial discharges from the north Italian
rivers (Po, Adige, Brenta, Piave, Tagliamento, Isonzo) as well as from
direct urban effluents.
In this chapter attention will be paid to the flora of the . northern
Adriatic, where deleterious effects of sewage and industrial wastes on
marine ecosystems are the most drastic.
Local degradation of benthic communities was found on the one hand
(Fedra et al. 1976; Zavodnik 1976, 1977; Ott and Fedra 1977 and
Stachowitsch 1984; Stachowitsch and AvCin 1988), and frequent and increased plankton blooms on the other (Revelante and Gilmartin 1976;
Gilmartin and Revelante 1983; Fanuko 1989; Malej 1983). Large inputs of
suspended and colloidally dispersed organic matter into the northern
Adriatic, together with excessive phytoplankton blooms occasionally create amorphous mucose aggregations (Herndl1988; Herndl and Peduzzi
1988; Stachowitsch et al. 1990), which have an additional impact on the
benthic communities.
The increased eutrophication of the Adriatic Sea and in particular of its
northern shelf area has profoundly changed the benthic algal vegetation in
terms of zonation patterns, leading algal association, floristic diversity and
biomass (Pignatti 1962; Golubic 1968, 1970; Munda 1974a, 1980a,b, 1982a,
1993a,b; Pignatti and de Christini 1976). The physico-chemical basis for
these changes is also: the increased amounts of suspended and colloidally
dispersed particles, resulting in increased turbidity; the input of fecal
coliform bacteria; detritus; detergents and heavy metals.
The level of pollution in the Gulf of Trieste was estimated by
Ghirardelli et al. (1973) and recently by Tusnik et al. (1989). During the
last few years, the northern Adriatic was repeatedly subjected to oxygen
deficiencies in the near-bottom water (Fedra et al. 1976; Faganeli et al.
1985). Critical values, where the presence of HzS could be expected, were
found locally. Simultaneously, a hypersaturation with oxygen at the
surface became increasingly more apparent.
Marine benthic algae are useful as indicator organisms in monitoring
various effects of pollution, as they are sessile and integrate the deleterious effects of diverse organic and inorganic pollutants over a longer time
span. As such they were studied in different areas (Borowitzka 1972;
Edwards 1972, 1975; Katzmann 1972, 1975; Rizzi-Longo 1972; Rueness
I.M. Munda
During the last few years, the benthic algal vegetation of the Adriatic
Sea has changed most probably because of severe pollution impact.
Especially in the shallow shelf area of the northern Adriatic, conditions
become locally critical, leading towards eutrophication and anoxia
(Degobbis et al. 1979; Degobbis 1989; Justic 1987; Stefanon and Boldrin
1982; Faganeli et al. 1985). This part of the Adriatic Sea receives a heavy
load of domestic wastes and industrial discharges from the north Italian
rivers (Po, Adige, Brenta, Piave, Tagliamento, Isonzo) as well as from
direct urban effluents.
In this chapter attention will be paid to the flora of the . northern
Adriatic, where deleterious effects of sewage and industrial wastes on
marine ecosystems are the most drastic.
Local degradation of benthic communities was found on the one hand
(Fedra et al. 1976; Zavodnik 1976, 1977; Ott and Fedra 1977 and
Stachowitsch 1984; Stachowitsch and AvCin 1988), and frequent and increased plankton blooms on the other (Revelante and Gilmartin 1976;
Gilmartin and Revelante 1983; Fanuko 1989; Malej 1983). Large inputs of
suspended and colloidally dispersed organic matter into the northern
Adriatic, together with excessive phytoplankton blooms occasionally create amorphous mucose aggregations (Herndl1988; Herndl and Peduzzi
1988; Stachowitsch et al. 1990), which have an additional impact on the
benthic communities.
The increased eutrophication of the Adriatic Sea and in particular of its
northern shelf area has profoundly changed the benthic algal vegetation in
terms of zonation patterns, leading algal association, floristic diversity and
biomass (Pignatti 1962; Golubic 1968, 1970; Munda 1974a, 1980a,b, 1982a,
1993a,b; Pignatti and de Christini 1976). The physico-chemical basis for
these changes is also: the increased amounts of suspended and colloidally
dispersed particles, resulting in increased turbidity; the input of fecal
coliform bacteria; detritus; detergents and heavy metals.
The level of pollution in the Gulf of Trieste was estimated by
Ghirardelli et al. (1973) and recently by Tusnik et al. (1989). During the
last few years, the northern Adriatic was repeatedly subjected to oxygen
deficiencies in the near-bottom water (Fedra et al. 1976; Faganeli et al.
1985). Critical values, where the presence of HzS could be expected, were
found locally. Simultaneously, a hypersaturation with oxygen at the
surface became increasingly more apparent.
Marine benthic algae are useful as indicator organisms in monitoring
various effects of pollution, as they are sessile and integrate the deleterious effects of diverse organic and inorganic pollutants over a longer time
span. As such they were studied in different areas (Borowitzka 1972;
Edwards 1972, 1975; Katzmann 1972, 1975; Rizzi-Longo 1972; Rueness