NPZD model

Reminerahzation of PON and DON to DIN is clearly a key process in models, and also provides some useful illustrations of the classification and evolution of models. The earliest NPZ models represented loss terms from phytoplankton and zooplankton as fluxes directly to the DIN pool. An NPZD model differs from an NPZ model in having an explicit compartment for detritus, or nonfiving organic matter (Edwards, 2001 Franks, 2002). Remineralization from this pool is most simply expressed as... 

Particle aggregation effects can also be parameterized in explicit formulations by making the sinking rate of the detritus a function of detritus concentration. For example. Hood et al. (2003) applied this kind of simple parameterization in an NPZD model to account for aggregation that can occur in diatom blooms. In their model phytoplankton sink at the rate... 

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