written by Susan Daniel
Last September, two GLC personnel (Allison Hrycik and Erik Hartnett) traveled to Lake Superior to sample aboard the EPA’s R/V Lake Guardian with several EPA researchers, crew members, and collaborators as part of the Cooperative Science and Monitoring Initiative (CSMI). Each year, the CSMI focuses on one of the Great Lakes, but since there was no sampling in 2020 due to the COVID-19 pandemic, we needed to sample two lakes this year to catch up. In addition to the Long-Term Biological Monitoring (LTM) that samples set stations in every lake each year, Lake Huron was intensively sampled in July and Lake Superior was sampled in September. After this year, we should be back on schedule for the other CSMI lakes, but for our laboratory that meant that we had 1.5x the samples that we normally collect.
The survey of Lake Superior took place September 21 through October 5, 2022. The crew had originally planned to sample 73 stations but had several snags along the way. Particularly stormy weather and hard substrate caused the EPA to cancel some of the stations. Then the Lake Guardian’s bow thruster began to leak. The bow thruster is an auxiliary propulsion device at the bow, or forward part of the ship, that aids in maneuvering the vessel. Anyone who has ever stayed on the Lake Guardian knows the sound of the bow thruster very well, as it’s a sure sign that we are approaching station or nearing our port. Without full use, it would be dangerous to attempt sampling because maneuverability is significantly more challenging. Due to the bow thruster leak and weather delays, the EPA made the difficult decision to cancel the remaining survey. In the end, 55 stations were successfully sampled.
Once the 164 successfully collected samples were returned to our laboratories, we started our work processing samples and enumerating species. These data can be used to understand the water quality of Lake Superior and the ecology of this pristine lake. We hired several new employees to make sure we had enough time to process samples collected during the LTM and CSMI Huron. Because of this big effort and amazing teamwork, we were able to process Lake Superior samples in under four months! Remarkably, we counted 11,880 individual organisms and identified 60 different taxa. Our researchers are now currently preparing our final
report for CSMI Superior that will be available in 2-3 months.
Image caption: Erik Hartnett pouring a benthic sample into the elutriator aboard the R/V Lake Guardian to remove excess sediment. Credit: Sebastian Paczuski
