Aquatic
In aquatic systems, primary production is typically measured using one of six main techniques:[11]
variations in oxygen concentration within a sealed bottle (developed by Gaarder and Gran in 1927)
incorporation of inorganic carbon-14 (14C in the form of sodium bicarbonate) into organic matter[12][13]
Stable isotopes of Oxygen (16O, 18O and 17O)[14][15]
fluorescence kinetics (technique still a research topic)
Stable isotopes of Carbon (12C and 13C)[16]
Oxygen/Argon Ratios [17]