A trek with Ankeny-based limnologists late in August lead miles away from any semblance of a town, down a gravel road bordered on both sides with tall stands of cornfields. The mission of the day was to sample a tributary of Little Beaver Creek by collecting water, sediment and aquatic-life samples, all of which will form a picture of the stream's health.

Decked out in waders and hauling woven backpacks full of bottles, nets and various instruments, the crew of four trudged between the dense rows of corn and through a thicket of trees to the tiny stream well hidden between two neighboring fields. Once at the bank, the scientists set off in different directions, working like a well-oiled, unified machine. Block nets were set at both ends of a 600-foot stretch of the stream to contain the specimens while the limnologists moved about. Water, sediment and periphyton samples were collected while others gathered aquatic insects using forceps, sieves and artificial substrates.

The quiet, intent mood was amplified when one of the crew strapped on a backpack electro shocker meant to shock (not kill) the fish for the gathering.

"We ID all the fish to species here at the stream and will use microscopes to ID the aquatic insects this winter. Once all of our data is collected and analyzed, we send the results to the IDNR," explains Limnologist Katie Spoelstra. "Water chemistry is only one way to measure stream health. Fish and bugs are also good indicators of water quality."

By lunchtime, the team had counted and identified hundreds of fish (saving 500 grams for fish tissue analyses), and collected containers of sediment, periphyton, water, and microscopic insects.

Nearly two months later, the limnologists in Ankeny and Iowa City have moved much of their work indoors, although teams will continue to collect water samples even during the harshest of winters. Through their steady stream of work, these sentinels continually gauge the health of Iowas waterways for all creatures that enjoy them.

For more information about the UHL limnology program, check out UHL's Limnology Section.