Abstract:
The effect of allelochemicals released by toxic species in plankton community is often taken into account to reveal plankton
biodiversity. Using a minimal chemostat model we show that the interaction between toxic and non-toxic phytoplankton
species with changing competitive effects among species due to allelopathy helps to promote the stable coexistence of many
species on a single resource and hence can solve the paradox of plankton. We emphasize toxic phytoplankton as a keystone
species that strongly uncovers its allelochemicals on other non-toxic phytoplankton and enhances the species persistence
and diversity in aquatic ecosystems. In addition, we analyze the consistency of ecosystem functioning and species
diversity using a number of approaches, such as sampling hypothesis with selection and complementarity effects, cascading
extinction–reinvasion, and examining system dynamics at different enrichment levels and toxicity. Our results suggest that
chemostats with one toxic and one or more nontoxic phytoplankton species can be used for the experimental verification
of the stable coexistence of many species on a single resource in aquatic ecology
