Studio del popolamento mesozooplanctonico marino costiero per la ricerca di nuovi indicatori ambientali
Author(s)
Aguzzi, Laura
Date Issued
March 7, 2008
Type
Doctoral Thesis
Abstract
This study focussed on the structure and spatio-temporal dynamics of
mesozooplanktonic marine populations collected over six years (2001-2007) along the
coast of the Latium region (middle Tyrrhenian Sea, Mediterranean Sea).
Five sampling sites plus one reference site were chosen as a part of a national
monitoring program (funded by Ministry of Environment and the Regional Agency for
Environmental Protection, ARPALazio). The aim of this program was to determine the
spatial distribution, seasonal patterns and inter-annual variability zooplankton of Italian
coastal waters. These characteristics of zooplankton populations normally require longterm
time series data, however, there are statistical methods that can be applied to
limited datasets that can highlight recurrent patterns and dominant taxa. The ultimate
goal of the project was to determine the response of zooplankton population dynamics
to changing environmental conditions and to assess their potential use as bioindicators.
Taxonomical analysis was performed on more than 600 samples collected every two
weeks. This analysis resulted in a list of 82 copepods and 4 cladoceran taxa (adult
specimens) within the study area. Copepods normally dominated during the study
period, with seven species comprising around 90% of the total adult assemblage
(Paracalanus parvus Oithona nana, Centropages ponticus, Acartia clausi, Euterpina
acutifrons, Acartia discaudata var. mediterranea and Oithona similis.
The seasonal cycle of averaged density values at community level showed two peaks.
The first peak (short duration, high maximum biomass) which occurred in April was
mostly composed of copepods. The second peak (long duration, lower maximum
biomass) which occurred in late-summer to early-autumn was initially dominated by
cladocerans followed by a shift in dominance to copepods in autumn.
Statistical analyses, including correspondence analysis, rank autocorrelation on 12
months with Spearman and Kendall coefficients and Mantel test were applied to the raw
data set from each station, each confirming the occurrence of temporal patterns.
Both Runs tests and Indicator Species Analyses indicated the existence of “species
assemblages”, groupings of taxa distinct to the different sites and to different periods
within the same site. Comparisons between the zooplankton community and water
quality parameters (CAM) showed a significant relationship highlighting a possible role
of zooplankton assemblages as bioindicators of coastal marine water quality.
Additional information
Dottorato di ricerca in Ecologia e gestione delle risorse biologiche
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