Date of Award


Degree Type


Degree Name

Departmental Honors


Chemistry and Biochemistry


Scientists who study aquatic ecosystems quickly notice a diversity of pathways that different microbes and organisms can use to metabolize nutrients found in common ponds or pools. Competition for vital resources, such as light and inorganic minerals, allow only certain organisms to grow in certain niches within these ecosystems. Rhodospirillum rubrum is a gram negative, photosynthetic bacteria that competes for light within aquatic ecosystems in order to survive. R. rubrum is believed to specifically absorb light for photosynthesis at wavelengths in the range of infrared light. It was found that R. rubrum indeed can grow in "dark", anaerobic environments by being grown purely on infrared light. This was facilitated in the lab by growing R. rubrum on pure infrared light and comparing the absorbance of these cultures with a control of R. rubrum grown using an incandescent light bulb (visible light). Because of these findings, it is believed that R. rubrum can grow in ponds and other aquatic environments where organic filters, such as algae pollution, have absorbed all visible light for photosynthesis. Furthermore, our data supports the fact that R. rubrum could hypothetically grow entirely off of infrared light in aquatic environments. Strains of unknown bacteria have been found to grow on pure infrared light with acetone as the carbon source.



Faculty Mentor

Scott A. Ensign

Departmental Honors Advisor

Alvan Hengge