Adding complex trophic interactions to a size-spectral plankton model: Emergent diversity patterns and limits on predictability

Publication year: 2011
Source: Ecological Modelling, In Press, Corrected Proof, Available online 14 June 2011

Neil S., Banas

A new model in the NPZ (nutrient–phytoplankton–zooplankton) style is presented, mechanistically simple but with 40 size classes each of phytoplankton (1–20μm) and small zooplankton (2.1–460μm), in order to resolve one level of trophic interactions in detail. General, empirical allometric relationships are used to parameterize both the optimal prey size and size selectivity for each grazer class, as is rarely done. This inclusion of complex predator–prey linkages and realistic prey preferences yields a system with an emergent pattern of phytoplankton diversity consistent with global ocean observations, i.e., a parabolic relationship between diversity (as measured by the Shannon evenness) and biomass. It…

 Highlights: ► Empirical reviews of zooplankton prey preferences were added to a new plankton model. ► A parabolic diversity–biomass relationship emerges, as seen in marine observations. ► The ecosystem’s response to nutrient supply is only partially predictable. ► Grazer selectivity has a strong effect on the level of predictability. ► Predictability at few-day and interannual timescales do not vary in concert.