Aquatic ecology and Biodiversity

Unit 5- Productivity

5.3.4. Carbon ¹⁴C method
Add radioisotope of carbon (¹⁴C) as bicarbonate, H¹⁴CO_3- and it is converted to labeled carbon by the algae. Incubate in light and dark bottles. Measure of roughly NPP (how much ¹⁴C is incorporated into the algae) using Liquid scintillation counter. Is more sensitive than oxygen method.
Problems
• ¹⁴C and ¹²C do not have the same reactivity
• Doesn’t measure ¹⁴C that entered the cell and then left by excretion or respiration before the end of the experiment