Biofilms are constantly forming all around us – both inside and out – and their creation can have grave impacts on our health. Notably, Biofilms are known to be a danger to our water quality due to their protection of bacteria harmful to chlorinated water supplies, including facilitation of increased metals and pathogens (Frontiers in, Preciado, Boxell, Soria-Carrasco, Martinez, Douterelo). With temperatures on the rise due to climate change, the impact of increased temperature on biofilm development is a relevant question, and one investigated by the scientists named above. They discovered that increased temperature aligned with a greater abundance of various types of bacteria, though the strength of the biofilm layers was not impacted. In our experiment, we're investigating how the temperature of an E. coli biofilm's environment would impact its decendents ability to produce biofilms. Though E.coli aren't usually a threat to humans, they are a common indicator of fecal contamination in water, and researching their response to temperature change in terms of biofilm creation can suggest the behavior of other bacteria under similar conditions.

In short, our procedure forced several generations of E.coli bacteria through the biofilm life cycle, and pushed them to evolve into stronger biofilm creators by transferring only successful bacteria (i.e., bateria formed a biofilm) to the next stage. However, during the bead transfer process (indicated on the left side of Figure 4), we kept one group at room temperature during growth (20°C), and the other at around 35°C in an incubator in the molecular genetics lab. After completing this forced evolution process, we took the last generation of bacteria that went through the biofilm life cycle, plated them, and allowed them to grow. Finally, a crystal violet assay was performed on colonies to test their ability to create biofilm.

Since our control acts as a baseline for the measurement of AU with no bacteria, and knowing the control and E2 group were not statistically different, we can assume that the cause of the low AU value for E2 at 35° was due to a mistake in either transferring bacteria, or performing the crystal violet assay. So, we've decided to consider our data without this experimental group, and use solely E1 to represent our 35° run. With this considered, our results suggest that there was a significant increase in biofilm capability in E.coli descended from bacteria grown in a warmer vs. room temperature climate. Although this agrees with our original hypothesis, due to the increase in our expected temperature, the explanation behind this claim must differ. Though 30° and 35° don't seem too different, that 5° change makes all the difference to E.coli; 30° is around their ideal temperature, while 35° puts puts them in a stressful environment. Consequently, only the strongest bacteria would thrive and form biofilms in such poor conditions, and the following generation would, through natural selection, inherit stronger and more adapted traits. This would cause them to be significantly stronger biofilm makers than the decedents of E.coli who's ancestors didn't have such extensive natural selection due to temperature at play.