title: Mathematical analysis of a nutrient-plankton system with delay.
abstract: A mathematical model describing the interaction of nutrient-plankton is investigated in this paper. In order to account for the time needed by the phytoplankton to mature after which they can release toxins, a discrete time delay is incorporated into the system. Moreover, it is also taken into account discrete time delays which indicates the partially recycled nutrient decomposed by bacteria after the death of biomass. In the first part of our analysis the sufficient conditions ensuring local and global asymptotic stability of the model are obtained. Next, the existence of the Hopf bifurcation as time delay crosses a threshold value is established and, meanwhile, the phenomenon of stability switches is found under certain conditions. Numerical simulations are presented to illustrate the analytical results.
authors.affiliation: College of Mathematics and System Sciences, Xinjiang University, Urumqi, 830046 Xinjiang China.
authors.forename: Mehbuba
authors.initials: M
authors.lastname: Rehim
authors.affiliation: College of Mathematics and System Sciences, Xinjiang University, Urumqi, 830046 Xinjiang China.
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Mathematics and System Sciences, Xinjiang University, Urumqi, 830046 Xinjiang China.
authors.forename: Ahmadjan
authors.initials: A
authors.lastname: Muhammadhaji
keywords: Hopf-bifurcation; Nutrient recycling; Stability; Time delay; Toxic phytoplankton