Preprint volume - SIBM

Pre-print Volume - Oral presentations
Topic 2: MARINE ORGANISMS AND ECOSYSTEMS AS MODEL SYSTEMS
C.G. DI CAMILLO 1 , M. BO 1 , I. BARTOLUCCI 1 , F. BETTI 1 , B. CALCINAI 1 , C. CERRANO 2 ,
M. COPPARI 1 , M. MARTINELLI 1,3 , S. PUCE 1 , G. BAVESTRELLO 1
1 DisMar, Università Politecnica delle Marche - 60131Ancona, Italia.
c.dicamillo@univpm.it
2 DipTeRis, Università degli Studi di Genova - 16132 Genova, Italia.
3 CNR-ISMAR - 60131 Ancona, Italy.
THE BENTHIC ASSEMBLAGE OF CONERO PROMONTORY: A MODEL
FOR THE STUDY OF SEASONAL CYCLES IN THE NORTH ADRIATIC
SEA
LA COMUNITÀ BENTONICA DEL PROMONTORIO DEL CONERO:
UN MODELLO PER LO STUDIO DEI CICLI STAGIONALI NEL NORD
ADRIATICO
Abstract – It is widely accepted that in the Mediterranean temperate waters several filter feeding organisms
undergo a seasonal life cycle characterized by alternate active phases and starvation periods with
production of resting stages. The warm season is considered as an adverse period for the majority of the
filter-feeders due to the scarcity of plankton production resulting in a marked oligotrophy of the waters.
The study of the seasonal cycle of several hard-bottom benthic species of the Conero Promontory (North
Adriatic Sea) showed, on the contrary, that most of them are active during summer. This situation, probably
representing a model for the entire North Adriatic hard-bottom communities, is due to extremely low winter
temperatures, high plankton availability all around the year and exploitation, as food source, of
meroplanktonic larvae mainly released during summer.
Key-words: benthos, seasonal cycles, plankton, Adriatic Sea.
Introduction - Marine benthic organisms of Mediterranean littoral areas show
seasonal trends of abundance, growth and reproduction. In particular several species,
mainly calcareous sponges, hydrozoans and ascidians, are active only during the
favorable season while they go through the adverse periods as resting stages
(Bavestrello et al., 2006). Studies conducted in the western Mediterranean Sea indicate
that the majority of the seasonal taxa undergoes to a cycle of growth and expansion in
winter while reduces the activity or enters to dormancy in summer. Although water
temperature and irradiance variations are usually considered as the main factors
triggering seasonal cycles, Coma et al. (2000) highlighted also the importance of food
availability in determining the life strategy of benthic suspension feeders. Most of these
species are active in winter-spring, when they exploit the plankton blooms, while they
reduce their activity during the warm, oligotrophic season. The western side of North
Adriatic Sea shows different geomorphological and hydrological characteristics respect
to the rest of the Mediterranean Sea, such as the shallowness of the basin, the high
sedimentation rate and the sharp thermal excursion between summer and winter.
Moreover, this coastline receives 20% of the total Mediterranean river inputs, mainly
from the Po river (Russo & Artegiani, 1996). The Italian coasts of the northern Adriatic
Sea generally are sandy except for limited rocky areas, such as Colle S. Bartolo
(Pesaro) and Conero Promontory (Ancona). These zones, together with scattered
substrates of anthropic origin, break the continuity of the sandy coast and may
represent important stepping stones for species dispersal.
The peculiarity of this area impels to deepen the knowledge concerning the life
histories of its benthic communities, still poorly studied. In this work the seasonal cycle
41 st S.I.B.M. CONGRESS Rapallo (GE), 7-11 June 2010
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