Theoretical studies on extinction in the gradostat.

A multistage continuous culture system in which nutrients (or substrate) are supplied in the form of gradients has been studied in the laboratory. Called a gradostat, it consists of several chemostats with adjacent vessels connected. Two mathematical models based on Michaelis-Menten kinetics in a gradostat with two culture vessels and two competing species of microorganisms for the cases where there is a gradient of one limiting substrate and there are opposing gradients of two limiting complementary substrates are investigated. Given the parameters of the system, we can answer the basic question as to which species survive and which do not and determine the limiting values.