488
R. La Ferla et al.
Table 1. Ranges. mean values and standard deviations (SD) of aminopeptidase activity (AMP). respiratory activity (R), bacterial biomass (BB) and heterotrophic bacteria (MA) together with temperature and salinity in areas A and B
Area A
n
Range
Mean
AMP
Jun '96
30
0.85-44.25
9.97
(pgC/lIh)
Feb'97
30
0.24-37.59
6.66
Jun '97
30
0.61-59.45
8.29
Feb'98
30
0.51-31.08
4.86
R
Jun '96
30
0.13-3.82
0.99
(JlgC/lIh)
Feb'97
30
0.03-0.44
0.19
Jun '97
30
0.19-17.40
2.29
Feb '98
30
0.01-1.33
0.38
BB
Jun '96
30
2.93-21.30
9.22
(JlgCIl)
Feb'97
30
6.83-37.40
14.80
Jun '97
2B
9.76-37.60
22.30
Feb'98
30
23.80-279
43.90
MA
Jun'96
30
60-11500
1200
(CFU/mI) Feb '97
30
45-4100
1329
Jun '97
30
40-2717
874
Feb'9B
30
55-1190
387
T"C
Jun '96
30
9.71-20.57
17.54
Feb'97
30
9.33-11.61
10.45
Jun '97
30
12.08-24.67
17.54
Feb'98
25
8.41-10.99
9.84
S
Jun '96
30
34.15-38.10
36.74
Feb'97
30
31.56-37.94
36.65
Tun '97
30
23.07-37.94
35.47
Feb'98
30
31.81-38.33
37.05
Table 2. Bacterioplankton cell volumes, biovolumes and morphotypes in the different seasons
Jnne'96 Feb '97 Jnne'97 Feb'98
Cell volumes (pm3)
0.155
0.048
0.138
0.021
Biovolume/mI
0.165
0.070
0.234
0.091
Morphotypes (%)
Cocci
37.54
60.07
25.91
79.38
Bacilli
46.84
35.91
47.87
15.98
Vibrios
9.97
3.02
21.04
4.12
Spriri1Iae
5.65
1.01
5.18
0.52
organic carbon oxidised by respiration was
equivalent to 20.0 mg C m- 2 h- 1 in warm periods
and decreased 7-fold in cold periods (2.9 mg C
m- 2 h- 1 ).
In area B, the distribution of AMP showed
AreaD
SD
n
Range
Mean
SD
10.72
32
0.14-27.27
7.60
9.06
8.85
23
0.03-28.82
6.00
9.01
14.59
30
0.49-8.02
3.09
2.64
8.60
27
0.35-11.16
3.66
4.09
0.84
32
0.09-1.01
0.37
0.25
0.11
23
0.06-0.63
0.24
0.15
3.20
30
0.20-4.03
1.40
1.03
0.28
27
0.08-1.28
0.45
0.32
5.22
32
1.04-15.50
7.97
3.04
6.05
23
2.20-41.20
7.72
8.55
7.69
30
3.00-18.40
9.32
4.16
45.60
27
4.60-15.50
9.74
2.69
2048
32
100-3132
820
673
1433
23
40-26500
5098
7785
687
30
100-1045
461
224
284
27
40-4950
1061
1190
5.58
36
9.79-21.55
18.28
3.49
0.60
23
7.80-11.72
10.64
1.13
4.32
28
12.59-21.87
17.76
3.59
0.97
26
7.05-11.99
10.14
1.86
1.49
36
35.18-38.22
36.70
1.03
1.59
23
32.76-37.94
37.04
1.47
2.89
30
35.91-38.01
37.19
0.62
1.77
27
33.69-38.55
37.13
1.82
again this trend but, in June 96, high activities
were also observed at the bottom, probably due
to down-welled fresh water input (salinity at bottom 35.2-35.7). In area B, R showed the coast-offshore decreasing gradient only in June 97. The
amount of organic carbon potentially hydrolysed
by AMP in both the seasons resulted similar
(40.2 and 42.8 mg C m- 2 h-l, in warm and cold
periods, respectively). Conversely, the organic
carbon oxidised decreased about 3-fold from 9.7
mg C m- 2 h- 1 in warm months to 3.5 mg C m- 2 h- 1
in cold months.
Pearson correlation coefficients computed
among the different examined parameters in the
whole water column are reported in Table 3.
Generally AMP and R were significantly correlated, with the only exception of February 97 in area
A. The BB, MA, AMP and R showed instead different correlations with other parameters in the
R. La Ferla et al.
Table 1. Ranges. mean values and standard deviations (SD) of aminopeptidase activity (AMP). respiratory activity (R), bacterial biomass (BB) and heterotrophic bacteria (MA) together with temperature and salinity in areas A and B
Area A
n
Range
Mean
AMP
Jun '96
30
0.85-44.25
9.97
(pgC/lIh)
Feb'97
30
0.24-37.59
6.66
Jun '97
30
0.61-59.45
8.29
Feb'98
30
0.51-31.08
4.86
R
Jun '96
30
0.13-3.82
0.99
(JlgC/lIh)
Feb'97
30
0.03-0.44
0.19
Jun '97
30
0.19-17.40
2.29
Feb '98
30
0.01-1.33
0.38
BB
Jun '96
30
2.93-21.30
9.22
(JlgCIl)
Feb'97
30
6.83-37.40
14.80
Jun '97
2B
9.76-37.60
22.30
Feb'98
30
23.80-279
43.90
MA
Jun'96
30
60-11500
1200
(CFU/mI) Feb '97
30
45-4100
1329
Jun '97
30
40-2717
874
Feb'9B
30
55-1190
387
T"C
Jun '96
30
9.71-20.57
17.54
Feb'97
30
9.33-11.61
10.45
Jun '97
30
12.08-24.67
17.54
Feb'98
25
8.41-10.99
9.84
S
Jun '96
30
34.15-38.10
36.74
Feb'97
30
31.56-37.94
36.65
Tun '97
30
23.07-37.94
35.47
Feb'98
30
31.81-38.33
37.05
Table 2. Bacterioplankton cell volumes, biovolumes and morphotypes in the different seasons
Jnne'96 Feb '97 Jnne'97 Feb'98
Cell volumes (pm3)
0.155
0.048
0.138
0.021
Biovolume/mI
0.165
0.070
0.234
0.091
Morphotypes (%)
Cocci
37.54
60.07
25.91
79.38
Bacilli
46.84
35.91
47.87
15.98
Vibrios
9.97
3.02
21.04
4.12
Spriri1Iae
5.65
1.01
5.18
0.52
organic carbon oxidised by respiration was
equivalent to 20.0 mg C m- 2 h- 1 in warm periods
and decreased 7-fold in cold periods (2.9 mg C
m- 2 h- 1 ).
In area B, the distribution of AMP showed
AreaD
SD
n
Range
Mean
SD
10.72
32
0.14-27.27
7.60
9.06
8.85
23
0.03-28.82
6.00
9.01
14.59
30
0.49-8.02
3.09
2.64
8.60
27
0.35-11.16
3.66
4.09
0.84
32
0.09-1.01
0.37
0.25
0.11
23
0.06-0.63
0.24
0.15
3.20
30
0.20-4.03
1.40
1.03
0.28
27
0.08-1.28
0.45
0.32
5.22
32
1.04-15.50
7.97
3.04
6.05
23
2.20-41.20
7.72
8.55
7.69
30
3.00-18.40
9.32
4.16
45.60
27
4.60-15.50
9.74
2.69
2048
32
100-3132
820
673
1433
23
40-26500
5098
7785
687
30
100-1045
461
224
284
27
40-4950
1061
1190
5.58
36
9.79-21.55
18.28
3.49
0.60
23
7.80-11.72
10.64
1.13
4.32
28
12.59-21.87
17.76
3.59
0.97
26
7.05-11.99
10.14
1.86
1.49
36
35.18-38.22
36.70
1.03
1.59
23
32.76-37.94
37.04
1.47
2.89
30
35.91-38.01
37.19
0.62
1.77
27
33.69-38.55
37.13
1.82
again this trend but, in June 96, high activities
were also observed at the bottom, probably due
to down-welled fresh water input (salinity at bottom 35.2-35.7). In area B, R showed the coast-offshore decreasing gradient only in June 97. The
amount of organic carbon potentially hydrolysed
by AMP in both the seasons resulted similar
(40.2 and 42.8 mg C m- 2 h-l, in warm and cold
periods, respectively). Conversely, the organic
carbon oxidised decreased about 3-fold from 9.7
mg C m- 2 h- 1 in warm months to 3.5 mg C m- 2 h- 1
in cold months.
Pearson correlation coefficients computed
among the different examined parameters in the
whole water column are reported in Table 3.
Generally AMP and R were significantly correlated, with the only exception of February 97 in area
A. The BB, MA, AMP and R showed instead different correlations with other parameters in the