Diatoms of North AmericaMark Edlund and Sylvia Lee taught the 54th annual offering of the class at Iowa Lakeside Lab. Visiting researchers included David Burge, Lynn Brant, Steve Main, Matthew Julius, and Jennifer Beals.
The class collaborated with Paul Hamilton, Canadian Museum of Nature, to isolate single cells of diatoms in the genera Didymosphenia and Gyrosigma for sequencing of chloroplast DNA. A very fine glass pipette was used to aspirate a diatom cell and transfer it to a sterile drop of water. This process was repeated until the cell was isolated from debris and contaminants, especially non-target algal cells. Each isolated cell was transferred to a PCR tube containing tissue stabilizer solution, RNAlater. Sequences from these isolated cells will be used in future class projects, such as diversity and spatial distribution of diatom genes, detection of cryptic species, and understanding the genetic basis of morphological species concepts.
The class also participated in a project, started in 1995, on diatom communities of the Ashfall Fossil Beds State Historical Park in Royal, Nebraska. This year, students took images of diatom valves or fragmenst encountered in two locations: 1) a sand layer representing the watering hole benthos and, 2) an ash layer representing the watering hole that became filled with ash after a supervolcanic eruption that occurred ~12 million years ago. These data will be used to make inferences about the aquatic environment before and during the ashfall event.
