Regulators of Dinitrogen Fixation

Energy source Nitrogen fixation is an energy-intensive process and the factors controlling rates of photosynthesis or the distribution of photosynthate within the nitrogen-fixing organisms 

FIGURE 8.49 Schematic showing biogeochemical controls regulating nitrogen fixation in wetlands and aquatic systems. Symbols represent positive (+) and negative (-) effects. (Adapted from Howarth et al., 1988.) 

Cyanobacteria are commonly found to dominate wetlands and aquatic systems under conditions of nitrogen limitation or when levels of other potentially limiting elements (e.g., phosphorus) are 

FIGURE 8.50 Biological nitrogen fixation in periphyton mats along eutrophic gradient in northern Everglades wetland. (From Inglett et al., 2004.) 

Temperature Like any other biological reactions, nitrogen fixation rates are influenced by temperature with 2io values around 2. Contrasting differences were noted in nitrogen fixation 

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