Study the "Strict Homeostasis" Assumption in Ecological Stoichiometry via Bifurcations

Hao Wang
Department of Mathematics and Statistics, University of Alberta

(December 3, 2013 10:20 AM - 11:15 AM)

Study the

Abstract

Not only carbon (C) but also nutrient elements such as nitrogen (N) and phosphorous (P) are pivotal for organismal growth, reproduction, and maintenance. Newly emerging mathematical models linking population dynamics with these key elements greatly improve historic trophic interaction models and resolve many existing paradoxes. Most of these models assume strict homeostasis in heterotroph and non-homeostasis in autotroph due to the fact that the stoichiometric variability of heterotroph is much less than that of autotroph. Via bifurcations we study when the "strict homeostasis" assumption is sound and when not. Incorporating light dependence on the growth of autotrophs, the resulting dynamics reveal a series of homoclinic and heteroclinic bifurcations in low light conditions giving the explanation for why microcosm experiments have had unreliable results in low light conditions.