Nitrogen and Primary Production

In many estuarine systems primary production by phytoplankton and other autotrophs is affected by N inputs and concentrations (e.g., Cloem, 2001 Howarth, 1988 Kelly, 2001 Nixon, 1992 Smith, 2003). For this review, we have compiled estimates of annual primary production and simple models used to relate production to nutrient conditions. We also discuss the evolution of thinking concerning nutrient limitation of pelagic primary production in estuaries. Finally, we review the conceptual models concerning benthic and pelagic primary production and consider the influence of N on these different autrotrophic components. 

Annual rates of phytoplankton primary production from 120 different estuarine and coastal marine systems were organized in a frequency plot (Fig. 18.20). The most 

We also compiled reports of statistical models developed to relate primary production or algal biomass to N (Table 18.5). AH but one of these were generated during the last two decades, and the models take a variety of forms, for example, using N 

Location X (units) variable, Y (units) Predictive equation r jn Reference 

Multiple estuaries and Univ RI MERL DIN-loading (mol N m year ) (g C m year ) logy= 0.441og (X) + 2.33 0.93/19 Nixon et al., 1996 

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