CHAPTER 33
Distribution of Meio- and Macrofaunal Assemblages in
Anthropogenically Impacted Coastal Sediments (NW Mediterranean)
A. Covazzi Harriague, M. Chiantore, E. Piccione, L. Maliardi, and G. Albertelli
ABSTRACT
Meio- and macrofaunal assemblages in front of Genova and Savona were studied in order to
evaluate their structure in anthropogenically impacted coastal sediments. In the study area,
sediment particle size clearly decreases with depth, while their organic matter content shows a
clearly increasing pattern. Hydrocarbons show top values at 20 m depth in front of Genova and
at SO m depth in front of Savona. In the whole considered area mollusc and echinoderm assemblages evidence higher densities and species number at 20 m depth. Herein a transition zone is
observed where species characteristic of organic enrichment and sediment instability, such as
the bivalves Corbula gibba and Thyasira flexuosa, reach top densities. Suspension-feeders dominate at 10 m,at 50 m deposit-feeders turn out dominant, while at 20 m these alternative feeding
strategies coexist. Meiofauna abundance and number of taxa reached top values at 10m depth
in front of Genova as well as in front of Savona.
Introduction
For some 30 years much attention has been
focused on man induced changes on soft-bottom macro benthic communities in the Western
Mediterranean Sea under chronic pollutant
input, due to domestic and industrial wastes
(Bellan 1967, 1984, 1985; Glemarec and Hily
1981; Bourcier 1982). Bottom sediments constitute a sort of record of environmental processes
and, consequently, vehiculate man induced pollutants to benthic organisms (Reish 1972). This
kind of pollution induces basic changes in structural parameters of benthic communities (species composition and number, number of individuals and biomass), more or less intensely
according to the input characteristics, recovery
capacity and pristine conditions (Zajac and
Witlach 1982; Bellan 1985). While most sensible
species disappear, they are replaced by few
opportunistic species (Sandberg 1994; Heip
1995).
More recently, for a variety of reasons (short
generation time, life cycles spent entirely within
the sediments), meiofauna has been suggested as
a pollution indicator with several implications in
routine biological monitoring (Heip 1980; Platt
and Warwick 1980;Vincx and Heip 1991),although literature dealing mainly with effects of
hydrocarbons on marine meiofauna is generally
contradictory and the pollution effects seem to
be dependent on spill size and habitat characteristics (Renaud-Mornant et al. 1981; Fleeger and
Chandler 1983; Danovaro et al. 1995) as well as
taxonomic grouping (Heip et al.198B). Generally.
nematodes appear to be relatively insensitive to
heavy oil conditions and, if affected, they seem to
recover rapidly. while copepods seem to be more
severely affected by hydrocarbons and to recover
more slowly than nematodes (Wormald 1976;
Giere 1979; Boucher 1980; Elmgren et al. 1980;
Bonsdorf 1981; Fricke et aI. 1981; Gee et al. 1992),
although evidences from experimental oil spills
reported an increase in copepod density (Naidu
et aI. 1978).
The aim of this work is to assess the structure of macro and meiobenthic littoral communities in front of Genova and Savona, trying to evaluate possible relationships among faunisticaI
and biocoenotical features, natural and man
Dipartimento per 10 Studio del Territorio e delle Sue Risorse, Universita di Genova, Viale Benedetto XV 5, 16132 Genova, Italy
F.M. Faranda, L. Guglielmo, G. Spezie (eds)
Mediterranean Ecosystem.: Structures and Processes
@ Springer-Verlag ltalia 2001
Distribution of Meio- and Macrofaunal Assemblages in
Anthropogenically Impacted Coastal Sediments (NW Mediterranean)
A. Covazzi Harriague, M. Chiantore, E. Piccione, L. Maliardi, and G. Albertelli
ABSTRACT
Meio- and macrofaunal assemblages in front of Genova and Savona were studied in order to
evaluate their structure in anthropogenically impacted coastal sediments. In the study area,
sediment particle size clearly decreases with depth, while their organic matter content shows a
clearly increasing pattern. Hydrocarbons show top values at 20 m depth in front of Genova and
at SO m depth in front of Savona. In the whole considered area mollusc and echinoderm assemblages evidence higher densities and species number at 20 m depth. Herein a transition zone is
observed where species characteristic of organic enrichment and sediment instability, such as
the bivalves Corbula gibba and Thyasira flexuosa, reach top densities. Suspension-feeders dominate at 10 m,at 50 m deposit-feeders turn out dominant, while at 20 m these alternative feeding
strategies coexist. Meiofauna abundance and number of taxa reached top values at 10m depth
in front of Genova as well as in front of Savona.
Introduction
For some 30 years much attention has been
focused on man induced changes on soft-bottom macro benthic communities in the Western
Mediterranean Sea under chronic pollutant
input, due to domestic and industrial wastes
(Bellan 1967, 1984, 1985; Glemarec and Hily
1981; Bourcier 1982). Bottom sediments constitute a sort of record of environmental processes
and, consequently, vehiculate man induced pollutants to benthic organisms (Reish 1972). This
kind of pollution induces basic changes in structural parameters of benthic communities (species composition and number, number of individuals and biomass), more or less intensely
according to the input characteristics, recovery
capacity and pristine conditions (Zajac and
Witlach 1982; Bellan 1985). While most sensible
species disappear, they are replaced by few
opportunistic species (Sandberg 1994; Heip
1995).
More recently, for a variety of reasons (short
generation time, life cycles spent entirely within
the sediments), meiofauna has been suggested as
a pollution indicator with several implications in
routine biological monitoring (Heip 1980; Platt
and Warwick 1980;Vincx and Heip 1991),although literature dealing mainly with effects of
hydrocarbons on marine meiofauna is generally
contradictory and the pollution effects seem to
be dependent on spill size and habitat characteristics (Renaud-Mornant et al. 1981; Fleeger and
Chandler 1983; Danovaro et al. 1995) as well as
taxonomic grouping (Heip et al.198B). Generally.
nematodes appear to be relatively insensitive to
heavy oil conditions and, if affected, they seem to
recover rapidly. while copepods seem to be more
severely affected by hydrocarbons and to recover
more slowly than nematodes (Wormald 1976;
Giere 1979; Boucher 1980; Elmgren et al. 1980;
Bonsdorf 1981; Fricke et aI. 1981; Gee et al. 1992),
although evidences from experimental oil spills
reported an increase in copepod density (Naidu
et aI. 1978).
The aim of this work is to assess the structure of macro and meiobenthic littoral communities in front of Genova and Savona, trying to evaluate possible relationships among faunisticaI
and biocoenotical features, natural and man
Dipartimento per 10 Studio del Territorio e delle Sue Risorse, Universita di Genova, Viale Benedetto XV 5, 16132 Genova, Italy
F.M. Faranda, L. Guglielmo, G. Spezie (eds)
Mediterranean Ecosystem.: Structures and Processes
@ Springer-Verlag ltalia 2001