110
3
Quantification of Early Diagenesis: Dissolved Constituents in Marine Pore Water
The dye emits a fluorescent light at a different
wavelength (610 nm). The intensity of this fluorescence depends on the concentration of the
substance to be measured that penetrates into the
resin by diffusion, directly at the site of measurement. The construction of such microoptodes,
and the first results of measuring oxygen at the
sediment/bottom water boundary were described
by Klimant et al. (1995, 1997), Glud et al. (1999)
and Kühl and Revsbech (2001). According to
Klimant et al. (1995), optodes can be developed
for a number of substances (e.g. pH, CO 2 , NH 3 ,
O 2 ). As yet, this new technology has only been
applied to oxygen measurements, i.e. in the form
of the microoptode. Presumably, the construction
details and the alchemy of the fluorescent dyes
will still be the object of current development.
So-called planar optodes were developed in
recent years, which, for example, allow us to draw
two-dimensional maps showing the oxygen
distribution in a sediment. The fluorescence
induced by oxygen can be measured and made
visible on a particularly processed stretch of foil
(e.g. Glud et al. 2001).
in-situ Incubations
The diffusive input of oxygen into the sediment
contributes to only one part of the whole oxygen
budget. An input of oxygen into the sediment conducted by macroscopic organisms must be considered to occur especially in the sediments of
shallow waters, and when the proportion of organic matter in the sediment is high. These procesFig. 3.24 Results of in situ incubation measurements. In both examples, a depletion of oxygen and nitrate and a
concomitant release of phosphate, silica, and carbonate was observed in incubation time lasting 30 hours. The concentration unit is µmol/kg, alkalinity is expressed in µmol(eq)/kg. (after Jahnke and Christiansen 1989).
time [hours]
time [hours]
time [hours]
oxygen
nitrate
phosphate
silicate
titration alkalinity
total carbon dioxide
( )
2400
2420
2440
2460
2480
3
4
5
6
7
2400
2420
2440
2460
2480
0
10
20
30
40
100
120
140
160
180
-2
0
2
4
6
0
1 0
2 0
3 0
0
1 0
20
30
0
1 0
2 0
3 0
time [hours]
time [hours]
time [hours]
oxygen
nitrate
phosphate
silicate
titration alkalinity
total carbon dioxide
2400
2420
2440
2460
2480
3
4
5
6
7
2400
2420
2440
2460
2480
0
10
20
30
40
100
120
140
160
180
-2
0
2
4
6
0
1 0
2 0
3 0
0
1 0
20
30
0
1 0
2 0
3 0
Benthic Chamber Results - Santa Monica Basin Oct 87 ROSE 3
Benthic Chamber Results - Santa Monica Basin Oct 87 ROSE 2
3
Quantification of Early Diagenesis: Dissolved Constituents in Marine Pore Water
The dye emits a fluorescent light at a different
wavelength (610 nm). The intensity of this fluorescence depends on the concentration of the
substance to be measured that penetrates into the
resin by diffusion, directly at the site of measurement. The construction of such microoptodes,
and the first results of measuring oxygen at the
sediment/bottom water boundary were described
by Klimant et al. (1995, 1997), Glud et al. (1999)
and Kühl and Revsbech (2001). According to
Klimant et al. (1995), optodes can be developed
for a number of substances (e.g. pH, CO 2 , NH 3 ,
O 2 ). As yet, this new technology has only been
applied to oxygen measurements, i.e. in the form
of the microoptode. Presumably, the construction
details and the alchemy of the fluorescent dyes
will still be the object of current development.
So-called planar optodes were developed in
recent years, which, for example, allow us to draw
two-dimensional maps showing the oxygen
distribution in a sediment. The fluorescence
induced by oxygen can be measured and made
visible on a particularly processed stretch of foil
(e.g. Glud et al. 2001).
in-situ Incubations
The diffusive input of oxygen into the sediment
contributes to only one part of the whole oxygen
budget. An input of oxygen into the sediment conducted by macroscopic organisms must be considered to occur especially in the sediments of
shallow waters, and when the proportion of organic matter in the sediment is high. These procesFig. 3.24 Results of in situ incubation measurements. In both examples, a depletion of oxygen and nitrate and a
concomitant release of phosphate, silica, and carbonate was observed in incubation time lasting 30 hours. The concentration unit is µmol/kg, alkalinity is expressed in µmol(eq)/kg. (after Jahnke and Christiansen 1989).
time [hours]
time [hours]
time [hours]
oxygen
nitrate
phosphate
silicate
titration alkalinity
total carbon dioxide
( )
2400
2420
2440
2460
2480
3
4
5
6
7
2400
2420
2440
2460
2480
0
10
20
30
40
100
120
140
160
180
-2
0
2
4
6
0
1 0
2 0
3 0
0
1 0
20
30
0
1 0
2 0
3 0
time [hours]
time [hours]
time [hours]
oxygen
nitrate
phosphate
silicate
titration alkalinity
total carbon dioxide
2400
2420
2440
2460
2480
3
4
5
6
7
2400
2420
2440
2460
2480
0
10
20
30
40
100
120
140
160
180
-2
0
2
4
6
0
1 0
2 0
3 0
0
1 0
20
30
0
1 0
2 0
3 0
Benthic Chamber Results - Santa Monica Basin Oct 87 ROSE 3
Benthic Chamber Results - Santa Monica Basin Oct 87 ROSE 2