In late May, Mill River educators finally got INTO the river, after a year of workshops exploring Mill River mapping, environmental art, history and storytelling. For the fourth RIVER workshop of 2021-22, Brita Dempsey facilitated a streamside investigation of macroinvertebrates, in collaboration with Jan Szymaszek. Educators from local schools and the Smith College Museum of Art dipped their feet and nets into the river and were enthralled to learn about the secret lives and huge significance of tiny organisms living underneath the water.
Brita’s enthusiasm sparkled like the afternoon sun on the stream as she turned over stones and showed us creatures clinging to the shiny undersides. Many of us were surprised to discover that squiggles we might have mistaken for scratches or dirt were in fact immature aquatic insects. One teacher reflected how exciting it was to “discover things that we hadn’t seen before that were there all along.”
Bursting with questions about the wriggling nymphs we observed up close in tubs of water, Brita directed us to diagrams to help us identify and categorize what we were seeing. Brita and John Sinton shared their expertise about macroinvertebrate behavior, including the distinction between “clingers” and “swimmers.” John helped us imagine how caddisflies “connect the river” by making webs of silk thread to catch their food.
“Is the caddisfly eating the mayfly, or eating algae off the mayfly?” Drama abounded in the squirming world we observed through magnifying glasses. Everyone noticed something different. One teacher was surprised to find many different kinds of mayflies. Another teacher reflected on a “renewed sense of reverence for the river.” Everyone felt a sense of wonder and curiosity: “mystery makes me curious to find out what else I can learn!” The more we learned, the more we began to appreciate the significance of macroinvertebrates as river keepers and indicators of stream health. The critters we found, including caddisflies, mayflies and stoneflies, are classified as “Group One” organisms, indicating good water quality.
As if she had planned a final trick to conclude her magic show, Brita brought our attention to an insect on a rock, in a spotlight of sunshine, right at our feet. It was a winged adult stonefly! We were thrilled to see the adult version of nymphs we had just observed in the water. Brita smiled at our enthusiasm, “It’s so cool to get to share this with people!” Brita followed up with a curated list of resources (see below) to help all of us share the wriggling world of macroinvertebrates with students and colleagues. Happy summer and we hope you will get into a river near you and investigate what’s living under the water!
Written by Carol Berner, on behalf of the Mill River Guides
Resources shared by Brita Dempsey:
- Stroud Water Research Center, Identification Guide to Freshwater Macroinvertebrates
- Macroinvertebrates.org
- Leafpack Network (great way to collect critters without a net)
- Rock Pack Experiment (caddisflies are awesome!)
- Wade Institute has a PD workshop that includes Macroinvertebrate sampling
