ABSTRACT
Primary production is controlled by a combination of physical (e.g., residence time, temperature, and light), chemical (e.g., nutrients), and biological (e.g., grazing) conditions. Primary production can be represented by Equation 16.1 (Stumm and Morgan 1996; Chapra et al. 2007; assuming for this example that ammonia is used as a substrate):
106CO NH HPO H O C H O N P O2 2
R 106 263 110 16 1 2 + + + →← +
+ −16 106 1064 42 + +14H (16.1)
where P refers to production and R to respiration. So, while plants may produce biomass in the presence of light, they also respire. The result produces diel variations in oxygen and carbon dioxide concentrations.
