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C. Brugnano et al. / Journal of Marine Systems 81 (2010) 312–322 321
late autumn is probably related to their capability to survive and offshore gradient and depth layers. In particular, further researches on
reproduce in oligotrophic waters that characterize this period the relationship among chlorophyll a, microzooplankton and cope-
(Licandro and Icardi, 2009). Diverse feeding strategies are displayed pods could be necessary in order to understand the role of autumn
by these two genera that make them efficient at ingesting food at low copepod communities in the planktonic food web, and how the biotic
concentrations: Clausocalanus feeding behaviour, as observed in and physical factors could determine the copepod spatial distribution
C. furcatus, consists in capturing cells by direct interception when patterns in the Egadi Island Archipelago.
moving rapidly (Mazzocchi and Paffenhofer, 1999). So this species is
adapted to a wide range of food and may efficiently filter by the Acknowledgements
particular morphology of its filtering appendages (Peralba and
Mazzocchi, 2004). Oithona feeding on moving prey (Uchima and Financial support for this research was given by MIUR, CoNISMa,
Hirano, 1988; Svensen and Kiorboe, 2000), is an omnivorous and FIRB 2003.
opportunistic that prefers ciliate and flagellates (Lonsdale et al., Many thanks go to officers and crew of the research vessel
2000), but ingests also diatoms (Turner, 1986; Hopkins and Torres, Universitatis and technicians involved in the BIONESS sampling
1989). procedures, for their excellent cooperation in the field work. We are
Clausocalanus is a surface-living genus, although some species grateful to all anonymous reviewers, who allow us to improve our MS
have a spatial distribution ranging from surface to great depth with their suggestions.
(Raymont, 1983; Scotto di Carlo et al., 1984). Around the Egadi Island
area, the spatial distribution pattern of Clausocalanus species was
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