Diatoms, an abundant and widespread group of golden algae, are one of the most important members of virtually all aquatic communities, often providing much of the primary production of biomass for other organisms. With diatoms situated at the base of the food chains, it becomes critical to understand how diatoms succeed in their environments, and how different environmental conditions affect their viability. This project is designed to better understand the way in which diatoms are able to move through their environment, and how this movement helps them compete (both with other algae and between different diatom species) for limited local resources such as light and nutrients. Because these cells are confined within a hardened glass-like cell wall, their movement is thought to be generated by the secretion of mucilage through specialized slits in their cell wall, and the subsequent force exerted on the adhering mucilage strands. The PI plans to examine the process of diatom movement by: 1) analyzing the number and distribution of direct contact sites made by diatoms with the underlying surface as a function of changes in the environmental conditions (light, temperature, etc.); 2) analyzing the ability of diatoms to adhere to surfaces under different environmental conditions in the presence of flowing water; and 3) analyzing the effect of environmental conditions on the ability of diatoms to aggregate in areas of light.
The experiments will be carried out at DePaul University, a teaching-oriented urban university, with a research team that includes several undergraduates. The techniques used in this study, such as video-microscopy and interference reflection microscopy, using various filters and environmental cell chambers to regulate the light, temperature, water, and surface conditions, are relatively easy for students to learn quickly. This project therefore provides an opportunity to not only increase our knowledge of how the behavior of diatoms is affected by the environmental conditions, but also offer an exciting training opportunity for a number of undergraduate students to get involved directly in cellular and environmental research.
