Degree
Master of Science
Program
Biology
Supervisor
Charles G. Trick
2nd Supervisor
Irena F. Creed
Joint Supervisor
Abstract
The cyanobacterium M. aeruginosa is an important bloom former in freshwater environments. We investigated the growth, photosynthesis and toxin contents of two toxic strains of M. aeruginosa, CPCC 299 and CPCC 300, under a combination of nitrogen supply (nitrate or ammonium) and depleted or replete Molybdenum (Mo) and/or Iron (Fe) concentrations. When Mo and Fe were supplied at growth-replete levels, M. aeruginosa grew equally well on nitrate and ammonium. Reducing Fe dramatically reduced growth rate efficiency when the cells were supplied with nitrate, but not with ammonium. In contrast, the removal of Mo from the medium did not impair growth or nitrogen utilization rates regardless of the form of nitrogen available but impacted negatively photosynthetic capacity. Experiments designed to assess if excess Fe could “mask” the Mo-limitation by replacing key physiological processes with Fe revealed the opposite was true: addition of Mo alleviated the stresses associated with Fe-limitation.
Recommended Citation
Xu, Yan, "Molybdenum and Iron Interactions as Micronutrients for Growth of a Freshwater Cyanobacterium, Microcystis Aeruginosa" (2015). Electronic Thesis and Dissertation Repository. 3293.
https://ir.lib.uwo.ca/etd/3293