CHAPTER 23
Distribution and Ecology of Mesozooplankton in the Northern and
Central Adriatic Sea
O. Sidoti, G. Zagami, A. Granata, G. Brancato, L. Guglielmo, and M. Campolmi
ABSTRACT
Within the framework of the Prisma 2 Project, four oceanographic cruises were carried out in the
central and northern Adriatic Sea from June 1996 to March 1997. Samples were collected both
by BIONESS electronic multi net (204 samples from 54 sites) and by WP2 (101 samples from 19
sites) along inshore-offshore sections. The spatial-temporal distribution of the zooplankton
community was analysed in relation to the variability of physico-chemical and biological parameters. The seasonal succession of the zooplankton community was characterized by an inversion of the dominance ratio between cope pods and dadocerans. In early June, copepods and
dadocerans represent on average 52 and 20% of the zooplankton community, respectively,
while in late summer they represent 17 and 66%. During late spring-summer, the dadoceran
population was clearly dominated by Penilia avirostris, which in some coastal sites constituted
more than 90% of the zooplankton. In the coastal zone, the cope pod population was characterized by low species diversity and greater dominance of A. clausi, P. parvus and T. stylifera (73% of
the population). In the offshore zone of the neritic system, there was instead a more homogeneous copepod species composition. Because of their spatial distribution patterns, P. elongatus
and T.Jongicornis, typical of estuarine environments, can be considered as hydrological indicator
species of different water masses of the Adriatic neritic system. In winter, the zooplankton community was characterized by strong dominance of copepods (31 species identified), on average
constituting 75% of the zooplankton, followed by invertebrate larvae, appendicularians, dadocerans, siphonophores and chaetognaths. From our analysis of the spatial distribution of the
zooplankton community, we have formulated a preliminary trophic model concerning the association of ecologically similar species in the water masses of the Adriatic neritic system.
Introduction
The zooplankton of the Adriatic Sea has been
studied since the first half of the last century
(Claus 1881; Car 1890; Graeffe 1900; Steuer
1902a, b, 1910a, b). In particular. many studies
have been conducted on the distribution of
copepods (Hure et al. 1980; Specchi and Fonda
Umani 1987,1996; Ghirardelli et al. 1989; Fonda
Umani et al. 1992) and on their medium and
long term variations (Regner 1985).
Particular morphological, hydrological and
hydrodynamic features of the northern Adriatic
Sea influence the abundance and distribution of
mesozooplankton. In fact, this basin is characterized by abundant biomass (Benovic et al. 1984)
which decreases southward. However, the structure of the mesozooplankton community
exhibits low diversity in the northern zone,
which increases toward the southern zone and
offshore (Fonda Umani et al. 1992). Hure et al.
(1980) have identified three copepod communities: estuarine, coastal and oceanic.
The main aim of this study was to analyse the
spatial distribution of the mesozooplankton in
relation to the variability of physico-chemical
and biological factors. In addition, we studied the
structure of the community in order to formulate a preliminary trophic model of the northern
and central Adriatic neritic system.
Dipartimento di Biologia Animale ed &ologia Marina, Universita di Messina, Salita Sperone 31,98166 Messina, Italy
EM. Faranda, L. Guglielmo, G. Spezie (eds)
Mediterranean Ecosystems: Structures and Processes
@ Springer-Verlag ltalia 2001
Distribution and Ecology of Mesozooplankton in the Northern and
Central Adriatic Sea
O. Sidoti, G. Zagami, A. Granata, G. Brancato, L. Guglielmo, and M. Campolmi
ABSTRACT
Within the framework of the Prisma 2 Project, four oceanographic cruises were carried out in the
central and northern Adriatic Sea from June 1996 to March 1997. Samples were collected both
by BIONESS electronic multi net (204 samples from 54 sites) and by WP2 (101 samples from 19
sites) along inshore-offshore sections. The spatial-temporal distribution of the zooplankton
community was analysed in relation to the variability of physico-chemical and biological parameters. The seasonal succession of the zooplankton community was characterized by an inversion of the dominance ratio between cope pods and dadocerans. In early June, copepods and
dadocerans represent on average 52 and 20% of the zooplankton community, respectively,
while in late summer they represent 17 and 66%. During late spring-summer, the dadoceran
population was clearly dominated by Penilia avirostris, which in some coastal sites constituted
more than 90% of the zooplankton. In the coastal zone, the cope pod population was characterized by low species diversity and greater dominance of A. clausi, P. parvus and T. stylifera (73% of
the population). In the offshore zone of the neritic system, there was instead a more homogeneous copepod species composition. Because of their spatial distribution patterns, P. elongatus
and T.Jongicornis, typical of estuarine environments, can be considered as hydrological indicator
species of different water masses of the Adriatic neritic system. In winter, the zooplankton community was characterized by strong dominance of copepods (31 species identified), on average
constituting 75% of the zooplankton, followed by invertebrate larvae, appendicularians, dadocerans, siphonophores and chaetognaths. From our analysis of the spatial distribution of the
zooplankton community, we have formulated a preliminary trophic model concerning the association of ecologically similar species in the water masses of the Adriatic neritic system.
Introduction
The zooplankton of the Adriatic Sea has been
studied since the first half of the last century
(Claus 1881; Car 1890; Graeffe 1900; Steuer
1902a, b, 1910a, b). In particular. many studies
have been conducted on the distribution of
copepods (Hure et al. 1980; Specchi and Fonda
Umani 1987,1996; Ghirardelli et al. 1989; Fonda
Umani et al. 1992) and on their medium and
long term variations (Regner 1985).
Particular morphological, hydrological and
hydrodynamic features of the northern Adriatic
Sea influence the abundance and distribution of
mesozooplankton. In fact, this basin is characterized by abundant biomass (Benovic et al. 1984)
which decreases southward. However, the structure of the mesozooplankton community
exhibits low diversity in the northern zone,
which increases toward the southern zone and
offshore (Fonda Umani et al. 1992). Hure et al.
(1980) have identified three copepod communities: estuarine, coastal and oceanic.
The main aim of this study was to analyse the
spatial distribution of the mesozooplankton in
relation to the variability of physico-chemical
and biological factors. In addition, we studied the
structure of the community in order to formulate a preliminary trophic model of the northern
and central Adriatic neritic system.
Dipartimento di Biologia Animale ed &ologia Marina, Universita di Messina, Salita Sperone 31,98166 Messina, Italy
EM. Faranda, L. Guglielmo, G. Spezie (eds)
Mediterranean Ecosystems: Structures and Processes
@ Springer-Verlag ltalia 2001