TITLE:

A MODEL FOR THE DYNAMICS OF THIOBACILLUS FERROOXIDANS IN THE IRON CYCLE OF PYRITE MINE WASTES

DATE:

Friday, February 26th, 2010

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Miguel Dumett,
Jet Propulsion Laboratory, California Institute of Technology

ABSTRACT:

We model how bacteria Thiobacillus Ferrooxidans catalyzes the oxidation of pyrite by ferric ion, utilizing its products to survive in the acidic medium generated by a set of chemical reactions called the pyritic iron cycle. A non-dimensional analysis of the corresponding dynamical model shows the existence, under certain circumstances, up to four steady states with non-null equilibrium concentrations. The stability of the non-trivial equilibrium points is determined by using the Routh-Hurwitz conditions and the projection onto a subsystem. The Hopf bifucartion values for the bacteria catalytic effect parameter associated to one of the singular points is found numerically. The stability of the corresponding periodic oscillations and its stability is determined by calculating the first Lyapunov coefficient. This gives a possible explanation for the transitory oscillations of bacteria concentration and pH for the iron cycle, mentioned in the literature.

This is a joint work with James Keener.

HOST:

Jose Castillo

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