Macro- and Meiobenthic Distribution in Anthropogenically Impacted Sediment
257
(Plymouth Marine Laboratory), as well as classification according to the Bray-Curtis similarity
index (Bray and Curtis 1957).
Results
Sediment Features
GenovoArea
Data relative to grain size, sediment total organic
matter and hydrocarbon content in the Genova
area are showed in Table 1a. Sediment grain size
shows quite similar trends along the different
transects, decreasing with depth. Sandy fraction
dominated at the shallowest stations (B and C)
representing, on average. 91.3 and 75.7% respectively, while silt/clay fraction reaches its maximum percentage at the deepest station (D), on
average, 94.3%.
Total organic matter (TOM) content increases with depth, ranging on average between 3.3%
(10 m) and 8.5% (50 m).
Hydrocarbon concentrations in the sediments in front of Genova are relatively high.
Maximum values are observed values at 20 m
depth (on average 0.3 mg/g) and minimum
values at the shallowest stations (on average 0.1
mg/g).
Savona Area
Data relative to grain size, sediment total organic
matter and hydrocarbon content in the Savona
area are showed in Table lb. Similar to the trend
observed in front of Genova, sediment grain size
decreases with depth: the sand fraction constitutes on average 90.5% at 10 m depth and 81.4% at
20 mdepth.
Total organic matter content follows the
same increasing pattern with depth observed in
Genova.
Sediment hydrocarbon concentrations are sliThble la,b. Data relative to sampling depth, gravel, sand and silt/clay fractions, total organic matter (TOM: average ± standard deviation) and hydrocarbons (average ± standard
deviation) concentrations: a Genova, b Savona
Depth
Gravel
Sand Silt and Clay
TOM
Hydrocarbons
(m)
(%)
(%)
(%)
(%)
mglg
a
G7B
10
0.1
94.2
5.7
2.4±O.3
O.27±0.18
G7C
20
0
63.1
36.9
6.4±O.4
O.08±0.01
G7D
50
0.1
3.2
96.7
9.6±0.1
0.13±0.04
G8B
10
8.7
90.2
1.1
2.3±0.2
O.13±0.10
G8C
20
0
81.4
18.6
6.1±0.2
0.37±0.20
G8D
50
0
6.4
93.6
9.0±0.1
0.27±0.IB
G9B
10
1.4
94.3
4.3
2.3±0.2
G.03±o.oZ
G9C
20
0.3
76.9
22.8
4.7±0.6
ND
G9D
50
0.6
4.2
95.2
8.3±0.2
O.14±O.06
GlOB
10
0.3
86.3
13.4
6.0±0.2
0.laO.03
GlOC
20
0.1
81.4
18.5
4.B±0.2
0.JaO.31
GlOD
50
0.5
7.9
91.6
7.aO.1
O.08±0.O3
b
SIB
10
0.6
91.7
6.7
2.9±0.3
0.05±0
SIC
20
2.3
88.7
9.0
8.3±0.7
O.06±0.03
S2B
10
0.7
96.S
2.5
0.7±0.1
0.22±0.01
S2C
20
7.8
87.4
4.8
3.4±0.4
O.O8±0
S2D
50
0
21.4
78.6
6.4±O .. 2
O.29±0.14
S3B
10
12.8
83.0
4.2
3.6±0.4
0.19±O
S3C
20
5.9
67.9
26.2
6.0±0.5
0.18±O.1O
S3D
50
2.8
38.0
59.2
ND
O.14±0.02
257
(Plymouth Marine Laboratory), as well as classification according to the Bray-Curtis similarity
index (Bray and Curtis 1957).
Results
Sediment Features
GenovoArea
Data relative to grain size, sediment total organic
matter and hydrocarbon content in the Genova
area are showed in Table 1a. Sediment grain size
shows quite similar trends along the different
transects, decreasing with depth. Sandy fraction
dominated at the shallowest stations (B and C)
representing, on average. 91.3 and 75.7% respectively, while silt/clay fraction reaches its maximum percentage at the deepest station (D), on
average, 94.3%.
Total organic matter (TOM) content increases with depth, ranging on average between 3.3%
(10 m) and 8.5% (50 m).
Hydrocarbon concentrations in the sediments in front of Genova are relatively high.
Maximum values are observed values at 20 m
depth (on average 0.3 mg/g) and minimum
values at the shallowest stations (on average 0.1
mg/g).
Savona Area
Data relative to grain size, sediment total organic
matter and hydrocarbon content in the Savona
area are showed in Table lb. Similar to the trend
observed in front of Genova, sediment grain size
decreases with depth: the sand fraction constitutes on average 90.5% at 10 m depth and 81.4% at
20 mdepth.
Total organic matter content follows the
same increasing pattern with depth observed in
Genova.
Sediment hydrocarbon concentrations are sliThble la,b. Data relative to sampling depth, gravel, sand and silt/clay fractions, total organic matter (TOM: average ± standard deviation) and hydrocarbons (average ± standard
deviation) concentrations: a Genova, b Savona
Depth
Gravel
Sand Silt and Clay
TOM
Hydrocarbons
(m)
(%)
(%)
(%)
(%)
mglg
a
G7B
10
0.1
94.2
5.7
2.4±O.3
O.27±0.18
G7C
20
0
63.1
36.9
6.4±O.4
O.08±0.01
G7D
50
0.1
3.2
96.7
9.6±0.1
0.13±0.04
G8B
10
8.7
90.2
1.1
2.3±0.2
O.13±0.10
G8C
20
0
81.4
18.6
6.1±0.2
0.37±0.20
G8D
50
0
6.4
93.6
9.0±0.1
0.27±0.IB
G9B
10
1.4
94.3
4.3
2.3±0.2
G.03±o.oZ
G9C
20
0.3
76.9
22.8
4.7±0.6
ND
G9D
50
0.6
4.2
95.2
8.3±0.2
O.14±O.06
GlOB
10
0.3
86.3
13.4
6.0±0.2
0.laO.03
GlOC
20
0.1
81.4
18.5
4.B±0.2
0.JaO.31
GlOD
50
0.5
7.9
91.6
7.aO.1
O.08±0.O3
b
SIB
10
0.6
91.7
6.7
2.9±0.3
0.05±0
SIC
20
2.3
88.7
9.0
8.3±0.7
O.06±0.03
S2B
10
0.7
96.S
2.5
0.7±0.1
0.22±0.01
S2C
20
7.8
87.4
4.8
3.4±0.4
O.O8±0
S2D
50
0
21.4
78.6
6.4±O .. 2
O.29±0.14
S3B
10
12.8
83.0
4.2
3.6±0.4
0.19±O
S3C
20
5.9
67.9
26.2
6.0±0.5
0.18±O.1O
S3D
50
2.8
38.0
59.2
ND
O.14±0.02