Art-Biology Interdisciplinary Research Project

December 13, 2012

By Clarrissa McWoodson '14

Last semester, Ceramics major John Henrikson worked with Bradley Biology Lecture Ted Fleming on a research project that examined and tested the bacteria found in ceramic clays.

"The hypothesis of the study was that specific bacteria are predominantly responsible for increased clay plasticity and there is a positive correlation between the presence of those microbes in aged clay and the working plasticity of that clay," Henrikson, a senior, said. Aged clays were evaluated for plasticity and fired shear strength relative to controls."

Henrikson took aged clay that was thought to be plastic, that is easily shaped or molded, and surveyed microbes present. Bacteria were found throughout the clays but very few fungi were found. After learning about the microbial community within the clay, Henrikson inoculated different sterile clays with bacterial isolates and found that, after a 10-day aging period, samples with bacteria were 10% more plastic than the controls.

"There are different theories among ceramic artists explaining why aged clays are better. Previous studies evaluated mixed or indigenous populations of microbes in native clays having varying properties. My study involved the use of specific microbes under controlled conditions. There is little investigation into clay plasticity "no one knows for sure why aging improves clay," Henrikson said.

He said it's believed the bacteria themselves do not make the clay more plastic but rather a polysaccharide secreted by some bacteria.

Throughout the experiment, Henrikson had to maintain sterile conditions with the clays since even the slightest contamination could produce erroneous data or disrupt the whole experiment.

Henrikson thanked Fleming for seeing "the value of my project" and acting as "a driving force behind me and my ideas." He added that Fleming has encouraged him to expand his research and questioning and Henrikson stressed how grateful he was to attend Bradley and for his rewarding experiences here.

"Ted's influence was absolutely imperative because I came in as an art student with an appreciation for science. He brought me up to speed on microscopic, microbe culture and aseptic techniques. He kept me on track and constantly reminded me about staying consistent, running controls, and not changing variables," Henrikson said.

Henrikson and Fleming are currently working with Dr. Keith Johnson, an associate biology professor, to analyze the DNA of the clay microbes. Henrikson plans to submit his project for online publication later.