Monitoring Mussels

By
Karen Jackson ’11
Shanghai, China
Geology

Derek Ochi ’12
San Diego, California
Biology

Fieldwork on the St. Croix River requires an interdisciplinary approach to the complicated task of monitoring the health of the river. Just an hour away from the Twin Cities, the St. Croix holds many species of endangered or threatened mussels. Our research brought us to the river daily in order to better understand how anthropogenic (human-caused) changes may affect their recovery. Students from the biology, geology and environmental studies departments brought different backgrounds and experience to the work.

The fieldwork entailed scuba diving to collect mussels and sediment, collecting water samples, and sieving substrate for mussels on Macalester’s pontoon boat the “Sea Tub” (affectionately named after the threatened mussel C. tub—Cyclonaias tuberculata). We worked rain or shine, the rocks were heavy, and some days the current was strong, but it’s amazing how a day on the job hardly felt like work when we were outdoors. As one of the first sites to be declared a National Scenic Riverway, the St. Croix is breathtaking, and our fellow students quickly become friends. 

In addition to monitoring the mussels on the St. Croix, students created their own research projects. It wasn’t as easy as it sounds, but we had three incredibly intelligent professors to guide us. After we created our projects, we helped each other collect data and process samples.

Karen’s research:
As a geologist, my project focused on sediment transport above the St. Croix Falls Dam. Below the dam there has been a 90% decrease in the juvenile mussel population, and a significant decrease in sediment size—an unusual occurrence below a dam. I researched the dam’s role in sedimentation for my senior honors thesis. We took sediment cores and something called Acoustic Doppler Current Profile readings. This was my second summer working on the river, and I learned so much about new equipment and independent research with the help of my thesis advisor Kelly MacGregor. 

Derek’s research:
My research focused on the relationship of an endangered species of mussel with the fish species that it parasitizes and develops on. This both distributes the mussel and provides it with necessary nutrients it needs to develop into an independent animal. The research involved collecting the juvenile mussel and utilizing both molecular and scanning electron microscope analysis. Summer research gave me a great opportunity to work with peers while learning new techniques and more about endangered species of Minnesota. This was my first summer doing research at Macalester, but with the guidance and support of our professors, it was a very enjoyable experience that I look forward to continuing.