Microbial Enzymatic Activities and Carbon Flux in the Adriatic Sea
489
two study areas. In area A, AMP and MA showed
most correlation both with hydrological and
metabolic parameters, as well as with the organic C pool, as opposed to BB. which was seldom
related with other parameters. The R showed a
good level of correlation with all other parameters in June 97 and February 98.
In area B, R,AMP and MA were nearly always
significantly correlated with each other and with
a considerable number of examined parameters
during the whole study period. Conversely to that
observed for area A, in area B, BB was highly correlated with a large number of parameters.
In both areas A and B, AMP and R resulted
negatively correlated with salinity while, if present, correlations with temperature were negative
in cold periods and positive in warm periods.
Discussion
No data on respiratory and aminopeptidase
activities are available yet in the Adriatic Sea.
Only Karner et a1. (1992) measured aminopeptidase activity in surface samples in spring (range
11.8-123 }lg C 1-1 h- 1 ) and summer {21.4-9.6 }lg C
2IlJ
150
100
50
Aminopeptidase actilfity (mg C m-:< h- 1 )
Area A
21]],----------------,
150
17
10
13
16'8' 11 b 113 b 13' a 15 b 20 iii
~E]~~~n-:,J ~b ,~ ,0 ~< ]
1 Q
7b
3b
10&
Sa
12b
11 a 16a 13b lab
153
20Q
AreaS
200 .,..-------~------------,
20lJ , - - - - - - - - - - - - - - - - ,
150
mo
50
200
19)
'00
9)
2 5 4 3 3 3 4 0 " 8 3 0
jun-SY
(29Al1
13. 19 b 14b 22. lSb 24 c
150
100
50
2IlJ
150
100
9)
feb-Sf
(5Ul)
1-c
53
23
3b
Bb
feb-S8
(3541)
1a
Sa
2b
7b
68
1061
1-1 h- 1 ), along a trophic gradient in the eastern
coast of the Northern Adriatic basin; these values
are in accordance with our data in the western
part of the Northern Adriatic Sea. In the superficial layers of the Mediterranean Sea various
authors have studied representative specific situations. In the Northern Adriatic basin, aminopeptidase activity reached the highest levels (7.45
and 5.09 }lg C 1-1 h-l, area A and B, respectively)
with respect to the up-welling area of the Straits
of Messina (6.36}lg C 1-1 h- 1 ; G. Caruso, personal
communication) and the Uguro-Provencal basin
(1.44 p.g C 1-1 h- 1 ; Karner and Rassoulzadegan
1995). The lowest values were determined in the
Sicily Channel near the Egadi Islands (0.03 }lg C
1-1 h- 1 • Caruso et al. 1998).
Respiration also reached the highest values in
the Northern Adriatic Sea. Respiratory activity in
the surface layers of the Mediterranean generally
decreased from west to east, from 0.94 p.g C 1-1 h- 1
in the Western Mediterranean Sea (Martinez et
al.1990) to 0.19}lg C 1-1 h- 1 in the Levantine basin
(Azzaro 1997) as well as from north to south.
from 0.96 and 0.62 }lg C 1-1 h- 1 in the Northern
Adriatic Sea (areas A and B, respectively) to 0.28
}lg C 1-1 h- 1 in the Otranto Straits (La Ferla et al.
Respitatory actilfity (mg C m-:t h- 1 )
Area A
35
35
30
30
25
25
feCI-97
20
20
(1.75)
15
15
10
10
5
5
.,
0
0
,.,
r--.
17
10
13
a 24
16. I1b 18 b 13. 15 b 20.
35
35
30
30
feb-SS
25
25
20
20
(4.2)
15
15
10
10
5
5
0
0
1. lb 3b 10. 6. 12 b
110 16. 13 b ,e b 15. 20.
AreaB
35
35
30
jun-96
30
feb-97
25
25
(2.58)
20
(44)
20
15
15
10
10
5
5
n
,-,
~
-
0
0
2. 43 33
'" .. 3D 1 c 5. 2 • 3b 8b
3 5 . . - - - - - - - - - - - - ,
~r~n _ _ ~: .-~--··I
30
25
20
15
10
5
o +L4-L-4JLLt.LLt-l-I-rLL<
13. 19b 141> 22. lab 240
oio 1 0 I 0 I C1 I 0 1 = .
1a
6a
2b
lb
5a
10a
Fig.2. Distribution of AMP and R integrated values in the layer O-to m; stations from coast to offshore on x-axis and mean integrated values in brackets are reported; in the stations indicated with an asterisk, there is a tendency to increasing R and AMP
towards the bottom
489
two study areas. In area A, AMP and MA showed
most correlation both with hydrological and
metabolic parameters, as well as with the organic C pool, as opposed to BB. which was seldom
related with other parameters. The R showed a
good level of correlation with all other parameters in June 97 and February 98.
In area B, R,AMP and MA were nearly always
significantly correlated with each other and with
a considerable number of examined parameters
during the whole study period. Conversely to that
observed for area A, in area B, BB was highly correlated with a large number of parameters.
In both areas A and B, AMP and R resulted
negatively correlated with salinity while, if present, correlations with temperature were negative
in cold periods and positive in warm periods.
Discussion
No data on respiratory and aminopeptidase
activities are available yet in the Adriatic Sea.
Only Karner et a1. (1992) measured aminopeptidase activity in surface samples in spring (range
11.8-123 }lg C 1-1 h- 1 ) and summer {21.4-9.6 }lg C
2IlJ
150
100
50
Aminopeptidase actilfity (mg C m-:< h- 1 )
Area A
21]],----------------,
150
17
10
13
16'8' 11 b 113 b 13' a 15 b 20 iii
~E]~~~n-:,J ~b ,~ ,0 ~< ]
1 Q
7b
3b
10&
Sa
12b
11 a 16a 13b lab
153
20Q
AreaS
200 .,..-------~------------,
20lJ , - - - - - - - - - - - - - - - - ,
150
mo
50
200
19)
'00
9)
2 5 4 3 3 3 4 0 " 8 3 0
jun-SY
(29Al1
13. 19 b 14b 22. lSb 24 c
150
100
50
2IlJ
150
100
9)
feb-Sf
(5Ul)
1-c
53
23
3b
Bb
feb-S8
(3541)
1a
Sa
2b
7b
68
1061
1-1 h- 1 ), along a trophic gradient in the eastern
coast of the Northern Adriatic basin; these values
are in accordance with our data in the western
part of the Northern Adriatic Sea. In the superficial layers of the Mediterranean Sea various
authors have studied representative specific situations. In the Northern Adriatic basin, aminopeptidase activity reached the highest levels (7.45
and 5.09 }lg C 1-1 h-l, area A and B, respectively)
with respect to the up-welling area of the Straits
of Messina (6.36}lg C 1-1 h- 1 ; G. Caruso, personal
communication) and the Uguro-Provencal basin
(1.44 p.g C 1-1 h- 1 ; Karner and Rassoulzadegan
1995). The lowest values were determined in the
Sicily Channel near the Egadi Islands (0.03 }lg C
1-1 h- 1 • Caruso et al. 1998).
Respiration also reached the highest values in
the Northern Adriatic Sea. Respiratory activity in
the surface layers of the Mediterranean generally
decreased from west to east, from 0.94 p.g C 1-1 h- 1
in the Western Mediterranean Sea (Martinez et
al.1990) to 0.19}lg C 1-1 h- 1 in the Levantine basin
(Azzaro 1997) as well as from north to south.
from 0.96 and 0.62 }lg C 1-1 h- 1 in the Northern
Adriatic Sea (areas A and B, respectively) to 0.28
}lg C 1-1 h- 1 in the Otranto Straits (La Ferla et al.
Respitatory actilfity (mg C m-:t h- 1 )
Area A
35
35
30
30
25
25
feCI-97
20
20
(1.75)
15
15
10
10
5
5
.,
0
0
,.,
r--.
17
10
13
a 24
16. I1b 18 b 13. 15 b 20.
35
35
30
30
feb-SS
25
25
20
20
(4.2)
15
15
10
10
5
5
0
0
1. lb 3b 10. 6. 12 b
110 16. 13 b ,e b 15. 20.
AreaB
35
35
30
jun-96
30
feb-97
25
25
(2.58)
20
(44)
20
15
15
10
10
5
5
n
,-,
~
-
0
0
2. 43 33
'" .. 3D 1 c 5. 2 • 3b 8b
3 5 . . - - - - - - - - - - - - ,
~r~n _ _ ~: .-~--··I
30
25
20
15
10
5
o +L4-L-4JLLt.LLt-l-I-rLL<
13. 19b 141> 22. lab 240
oio 1 0 I 0 I C1 I 0 1 = .
1a
6a
2b
lb
5a
10a
Fig.2. Distribution of AMP and R integrated values in the layer O-to m; stations from coast to offshore on x-axis and mean integrated values in brackets are reported; in the stations indicated with an asterisk, there is a tendency to increasing R and AMP
towards the bottom