Net Primary Production and Decomposition

In many wetlands NPP and decomposition are most limited by the availability of nutrients, especially N and P. For example, in a review of published data on nutrient limitations in North American bogs, fens, marshes and swamps, Bedford et al. (1999) found that a large proportion of the wetlands were either P limited or limited by both N and P, especially those occurring on organic soils. Only marshes had N P ratios in both live tissues and soils that consistently indicated N limitation, though the soil data suggested that the majority of swamps were also 

N limited. Nutrient availability also affects the composition of plant communities species richness and the presence of rare species often decline as nutrient availability increases beyond some threshold (Bedford et al., 1999). In addition to the inflow of nutrients with the water and sediment, there are complicated interactions between hydrology and nutrient availability that affect productivity and decomposition. Transformations of N and P under anaerobic conditions are discussed in Section 4.3. 

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Curdo, A., Ibanez, C., Day, J.W., and Prat, N. (2002) Net primary production and decomposition of salt marshes of the Ebre delta (Catalonia, Spain). Estuaries 25, 309-324. 

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