Paradox of the plankton

Coupled with the necessity of making the replicates similar is the elimination of a key ingredient of naturally synthesized ecological structures the spatial and temporal heterogeneity. Spatial and temporal heterogeneity are one key to species richness, as in "The Paradox of the Plankton" (Hutchinson 1961). Environmental heterogeneity is key to the establishment of metapopulations, a key factor in the persistence of species. 

Blooming of dinoflagellates is a complex affair, contemplated in the paradox of plankton . That is, at the equilibrium, resource competition models suggest that the number of coexisting species cannot exceed the number of limiting resources. In contrast, within nature, more species can coexist. A rationalization of these phenomena, possibly solving the paradox, may be found in species oscillations and chaos, without the need of advocating external causes (Huisman 1999). 

Oscillations can also arise from the nonlinear interactions present in population dynamics (e.g. predator-prey systems). Mixing in this context is relevant for oceanic plankton populations. Phytoplankton-zooplankton (PZ) and other more complicated plankton population models often exhibit oscillatory solutions (see e.g. Edwards and Yool (2000)). Huisman and Weissing (1999) have shown that oscillations and chaotic fluctuations generated by the plankton population dynamics can provide a mechanism for the coexistence of the huge number of plankton species competing for only a few key resources (the plankton paradox ). In this chapter we review theoretical, numerical and experimental work on unsteady (mainly oscillatory) systems in the presence of mixing and stirring. 

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