Page 2 - Spatial _distribution_Brugnano_2010

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Journal of Marine Systems 81 (2010) 312–322

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Journal of Marine Systems

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Spatial distribution and community structure of copepods in a central Mediterranean
key region (Egadi Islands—Sicily Channel)

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a,
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C. Brugnano ⁎, A. Bergamasco , A. Granata , L. Guglielmo , G. Zagami a
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Department of Animal Biology and Marine Ecology, Messina University, Salita Sperone 31, 98166 S. Agata, Messina, Italy
b
CNR, Institute for Coastal Marine Environment, Messina, Spianata S. Raineri, 86, 98122, Messina, Italy
article i nfo abstract
Article history: During an autumn oceanographic cruise in October 2004, 87 zooplankton samples were collected from 12
Received 4 August 2009 sites, located along inshore–offshore sections around the Egadi Island Archipelago, a central Mediterranean
Received in revised form 3 February 2010 key region. Zooplankton samples were taken by the electronic multinet BIONESS, equipped with a multi-
Accepted 12 February 2010
parameter probe system in order to measure simultaneously physico-chemical and biological factors
Available online 25 February 2010
(temperature, salinity, dissolved oxygen and fluorescence). Three different water masses were identified
from physico-chemical parameter analysis: MAW (0–50 m) widespread all around the study area; a water
Keywords:
Mediterranean Sea mass, which is most likely a mixture of western and eastern-origin waters, up to 300 m depth; and LIW in
Hydrography the 300–600 m layer, with a core salinity of 38.72–38.74 at the most offshore stations. Spatial diversity
Copepod biodiversity patterns of copepod assemblage were examined using species richness and Shannon–Wiener diversity
Spatial distribution indices. 107 copepod species were identified. Four major sample groups were identified by cluster analysis,
differing in species composition and abundances in relation to the depth and in-offshore environments. They
seemed to be only partly related to the different water masses and significantly correlated to temperature
and salinity. In the entire study area, the copepod abundances were markedly lower than those reported for
other regions of the Mediterranean Sea, but the species richness was relatively high, and similar to the
richest Mediterranean areas. This is probably due to geographical position of the Egadi Island Archipelago at
the entrance of Sicily Channel, where water mass exchange between Eastern and Western basins occurs.
© 2010 Elsevier B.V. All rights reserved.

1. Introduction in the offshore waters of Sicily Channel, Ionian Sea, Cretan Passage,
Rhode Area and Levantine Sea (Eastern Mediterranean). These
Mediterranean Sea is a marginal basin formed by two principal authors confirmed the general opinion of a decreasing W–E direction
sub-basins (the Western and the Eastern Mediterranean) that are diversity trend and that depth is the major factor affecting copepod
connected by Sicily Channel. Egadi Island Archipelago is located in the species vertical distribution. But very few is known about copepod
southernmost part of the Tyrrhenian Sea, at the entrance of Sicily assemblages of the Egadi Islands. On May–July 1970, Carli et al. (1973)
Channel where surface Modified Atlantic Water (MAW) flows carried out a study on surface zooplankton community from this area.
eastwards and deeper Levantine Intermediate Water (LIW) in the The main aim of their research was to find Thunnida eggs and larvae
opposite direction, following the natural along-Sicily conduit. in order to identify a nursery area for the species Thunnus thynnus in
From this point of view, this area plays an important role in order Egadi Island Archipelago. They used a net with a 500 µm mesh size,
to understand hydrodynamic and biological exchanges between which caused the lost of the smallest mesoplankton organisms.
Western and Eastern Mediterranean basins. The objective of this work is to study, from the coast to the open
The peculiar morphological, hydrological and hydrodynamic waters, the horizontal and vertical autumn copepod distribution. This,
features of Sicily Channel significantly influence distribution and to our knowledge, is the first contribution on spatial distribution of
composition of plankton and, in particular, copepod communities. copepod assemblages in relation to water mass structure and
Vives (1967) studied all Tyrrhenian Sea till the entrance of Sicily biological factors across the Egadi Island Archipelago.
Channel noting a decrease in zooplankton biomass in the SW–Center–
NW direction. More recent studies were carried out by Siokou- 2. Material and methods
Frangou et al. (1997) which compare copepod community structures
Within the framework of FIRB-BIODIVERSITY Project, “Character-
ization of pelagic environment of hydrographical area of Egadi
⁎ Corresponding author. Tel.: +39 0906765537; fax: +39 090393409. Islands”, an oceanographic cruise was carried out on October 2004.
E-mail address: cinzia.brugnano@unime.it (C. Brugnano). At all, 87 zooplankton samples were collected from 12 sites (Table 1),
0924-7963/$ – see front matter © 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jmarsys.2010.02.011