as high as possible is beneficial as it is the carbon which forms the
main component of lipids and carbohydrates.
In this chapter we present methods for determining dissolved
inorganic carbon (DIC), dissolved organic carbon (DOC), and
particulate organic carbon (POC). DIC is a direct measure of carbon
availability for photosynthesis, but how much of the DIC is in the
form of CO 2 is depending on the pH [4, 5]. As such, pH is a good
indicator of carbon availability as removal of CO 2 during photosynthesis increases pH (dissolved CO 2 is a weak acid). Measurements of
DIC are needed for most methods used to determine carbon fixation
(e.g., converting measurements of radiolabeled CO 2 fixation into
total carbon fixation). Some of the carbon fixed during photosynthesis may be released into the water as DOC. High concentrations
of DOC can inhibit growth and would in most cases increase bacterial production and biomass.
During DIC measurements, the carbonates within the sample
are converted with an acid to CO 2 which is detected with an
infrared gas analyzer [5]. The DOC method is based on hightemperature catalytic oxidation (>700
C) of a sample from
which particulate carbon has been removed by filtration and all
inorganic carbon has been removed by acidification and sparging
[4]. DOC can be determined together with total dissolved nitrogen
(TDN) and POC with particulate organic nitrogen (PON), which
is presented in a separate chapter. The method for determining
POC is based on filtration and is consequently a measure of all
particulate carbon in the culture, but unless there are other particles
in the cultivation water, it would be equal to the carbon found in
the algal biomass.
2 Materials
Use only analytical grade reagents.
2.1 Dissolved
Inorganic Carbon
1. 25–50 ml glass BOD bottles with stoppers.
2. 100 ml volumetric flasks.
3. Sodium bicarbonate (NaHCO 3 ).
4. Spatulas.
5. Analytical balance.
6. Small aluminum cups (approximately 5 mm Ø, 5 mm high).
7. Ultrapure water (e.g., Milli-Q).
8. 1 ml glass syringe.
9. Dissolved inorganic carbon analyzer with instrument-specific
carrier gas and oxidizing agents.
10. Concentrated nitric acid (65% HNO 3 ).
11. Refrigerator.
64
Jaana Koistinen et al.
main component of lipids and carbohydrates.
In this chapter we present methods for determining dissolved
inorganic carbon (DIC), dissolved organic carbon (DOC), and
particulate organic carbon (POC). DIC is a direct measure of carbon
availability for photosynthesis, but how much of the DIC is in the
form of CO 2 is depending on the pH [4, 5]. As such, pH is a good
indicator of carbon availability as removal of CO 2 during photosynthesis increases pH (dissolved CO 2 is a weak acid). Measurements of
DIC are needed for most methods used to determine carbon fixation
(e.g., converting measurements of radiolabeled CO 2 fixation into
total carbon fixation). Some of the carbon fixed during photosynthesis may be released into the water as DOC. High concentrations
of DOC can inhibit growth and would in most cases increase bacterial production and biomass.
During DIC measurements, the carbonates within the sample
are converted with an acid to CO 2 which is detected with an
infrared gas analyzer [5]. The DOC method is based on hightemperature catalytic oxidation (>700
C) of a sample from
which particulate carbon has been removed by filtration and all
inorganic carbon has been removed by acidification and sparging
[4]. DOC can be determined together with total dissolved nitrogen
(TDN) and POC with particulate organic nitrogen (PON), which
is presented in a separate chapter. The method for determining
POC is based on filtration and is consequently a measure of all
particulate carbon in the culture, but unless there are other particles
in the cultivation water, it would be equal to the carbon found in
the algal biomass.
2 Materials
Use only analytical grade reagents.
2.1 Dissolved
Inorganic Carbon
1. 25–50 ml glass BOD bottles with stoppers.
2. 100 ml volumetric flasks.
3. Sodium bicarbonate (NaHCO 3 ).
4. Spatulas.
5. Analytical balance.
6. Small aluminum cups (approximately 5 mm Ø, 5 mm high).
7. Ultrapure water (e.g., Milli-Q).
8. 1 ml glass syringe.
9. Dissolved inorganic carbon analyzer with instrument-specific
carrier gas and oxidizing agents.
10. Concentrated nitric acid (65% HNO 3 ).
11. Refrigerator.
64
Jaana Koistinen et al.