Competition for one nutrient with internal storage and toxin mortality

A density-dependent model of competition for one resource in the chemostat

This paper deals with a two-microbial species model in competition for a single-resource in the chemostat including general intra- and interspecific density-dependent growth rates with distinct removal rates for each species. In order to understand the effects of intra- and interspecific interference, this general model is first studied by determining the conditions of existence and local stability of steady states. With the same removal rate, the model can be reduced to a planar system and then the global stability results for each steady state are derived. The bifurcations of steady states according to interspecific interference parameters are analyzed in a particular case of density-dependent growth rates which are usually used in the literature. The operating diagrams show how the model behaves by varying the operating parameters and illustrate the effect of the intra- and interspecific interference on the disappearance of coexistence region and the occurrence of bi-stability region. Concerning the small enough interspecific interference terms, we would shed light on the global convergence towards the coexistence steady state for any positive initial condition. When the interspecific interference pressure is large enough this system exhibits bi-stability where the issue of the competition depends on the initial condition.

Chemical ecology of marine plankton

Covering: January 2013 to online publication December 2014This review summarizes recent research in the chemical ecology of marine pelagic ecosystems, and aims to provide a comprehensive overview of advances in the field in the time period covered. In order to highlight the role of chemical cues and toxins in plankton ecology this review has been organized by ecological interaction types starting with intraspecific interactions, then interspecific interactions (including facilitation and mutualism, host-parasite, allelopathy, and predator-prey), and finally community and ecosystem-wide interactions.