Ecology and Systematics of Diatoms course, 2017



Mark Edlund and Sylvia Lee taught the 55th annual diatom class at Iowa Lakeside Lab.


Neidium sacoense | Nitzschia sigmoidea |



When students collected samples from one of the buoys in Little Miller’s Bay, West Lake Okoboji, they found the attached diatoms Cymbella affinis and Gomphoneis olivaceum. That was not a surprise, but both species were producing gametangia and forming auxospores - diatom sex! Diatoms have an unusual life cycle, in which the very youngest cells are the biggest. Over their lifespan, diatom cells get smaller and smaller through vegetative cell division. The class was able to observe the different elements of the lifecycle, and found that these two species have a coordinated, synchronous life cycle. Students also measured sizes of the gametangial and initial cells to determine the minimum and maximum cell sizes.

The class cored the lake to obtain sediment and examine the paleolimnological record. The sediments had abundant Chironomus larvae living in fine organic material. The students were curious about the Chironomus diet, so they carefully dissected and examined the guts of Chironomus larvae for diatoms. They found that the species in the guts differed from species in the remainder of the sediments. As a result, the students propose that Chironomus sp. is a selective feeder, favoring small centric species.

Students contributed to the global citizen science database, in the project Ecology and Systematics of Diatoms. Students made 172 observations and identified 96 species from Iowa, Minnesota, Nebraska, Maryland, Florida, and Melbourne, Australia. Check out the links!

As a final project, each student prepared a species page for the Diatoms of the United States project. Look for the student pages to be coming online soon.


J.C. Kingston Fellowship

Teaching Fellowship | Shelly Wu

E.F. Stoermer Scholarship

Merit Scholarship | David Burge

C.W. Reimer Scholarship

Merit Scholarship | Eric Massa

Okoboji Foundation

Educational Support |

Roy J. Carver Charitable Trust

Student Microscopes and Imaging Systems |

Messengers of Healing Winds

Student Microscopes and Imaging Systems |


Sylvia Lee

Biologist, U.S. Environmental Protection Agency
Review Board, This Website

Mark Edlund

Senior Scientist, Science Museum of Minnesota
Review Board, This Website

Shelly Wu

Diatom Enthusiast,

David R.L. Burge

Lab Technician, St. Croix Watershed Research Station, Science Museum of Minnesota

Eric Massa

M.S. Student, Florida International University

Anna Drahos

Undergraduate student, Iowa State University

Jaclyn Rarick

Undergraduate student, University of Iowa

Stephanie Robson

Ph.D. Student, Monash University, Australia

Lynn Brant

Emeritus Professor of Geology, University of Northern Iowa

Steve Main

Professor, Retired, Wartburg College

This project was first entered on 13 June, 2017 by Sylvia Lee