PELLSTON, Mich. — It’s a late end to the 2024 floating field season for the smart buoy that gathers and transmits live environmental data on Douglas Lake off the shores of the University of Michigan Biological Station.
On Wednesday, Nov. 27, the day before Thanksgiving, staff at the more than 11,000-acre research and teaching campus in northern Michigan pulled the buoy out of the water.
“It had a lot of zebra mussels on it this year,” said Dr. John Lenters, senior research specialist.
Late Freeze
Before hauling the solar-powered device that monitors water quality back to shore for winter storage and cleaning, the team waited for the weather.
Lenters said the air temperature at the buoy got down to 33 degrees Fahrenheit the previous weekend, on the cusp of crossing the freezing threshold.
On Sunday, Nov. 24, the air temperature above the forest canopy at the 150-foot AmeriFlux tower briefly dipped below freezing for the first time this fall, just after 10 a.m.
That’s 25 days later than last year’s first subfreezing temperature at the AmeriFlux tower.
In 2023, the AmeriFlux tower recorded its first subfreezing temperatures of the season on Oct. 30, the day before Halloween — a Halloween that saw two inches of snow on the ground before sunrise.
However, the transition into the new year heralded the shortest season of lake ice cover recorded at UMBS at 70 days.
Longer Buoy Deployment
In the spring, UMBS staff put the buoy into the water for service on Friday, April 5, 2024 — the earliest since the field station added the device to its arsenal 14 years ago. The earliest previous deployment was April 18, 2012.
The end of the buoy’s 2024 deployment last week caps off an unusual year.
Lenters said the effects of last year’s record-setting mild winter have lingered almost to the next winter. Meteorological winter started Dec. 1, while astronomical winter begins Dec. 21.
“To some extent, we have the warm Great Lakes to ‘thank’ for this year's late freeze. Water temps are currently 4-6 F above normal,” Lenters said. “And that is due to last year's warm El Nino winter and also our abnormally warm autumn.”
Zebra Mussels
The longer-than-usual deployment likely played a role in the amount of aquatic invasive species stuck to the underwater portion of the buoy this year.
“It is normal for zebra mussels to colonize the buoy, but this is probably the most I've seen,” said Adam Schubel, resident biologist at UMBS.
Schubel said the amount varies from year to year. He is curious to explore whether it has to do with the timing of the buoy launch relative to when zebra mussels reproduce.
“With the short duration of lake ice, this past spring was one of our earliest deployments,” Schubel said. “Zebra mussels reproduce primarily in response to water temperature and food availability. I’d like to start monitoring and gathering data on when zebra mussel colonization occurs annually and seasonally in Douglas Lake.”
Zebra mussels are highly prolific. Schubel said one female can produce as many as one million eggs each year.
After being fertilized by sperm that male zebra mussels broadcast into the water, the larvae are suspended in the water column as they grow, swim, and find an object to latch on to, like a buoy or rock.
Local Landmark
The UMBS buoy will get a cleaning before redeployment in the spring.
The laboratory that bobs in the bay has become an annual landmark in the northern Michigan community, floating 24-7 in all weather conditions during the spring, summer and fall to monitor water quality and help us understand and protect our freshwater resources.
It is one of only a few buoys in the Great Lakes Observing System’s (GLOS) network stationed on an inland lake, rather than one of the Great Lakes.
Every year scientists at the northern Michigan field station deploy the device in Douglas Lake’s second deepest spot — a glacial kettle hole about 22 meters deep, or 72 feet, in South Fishtail Bay.
The buoy carries a suite of solar-powered sensors that provides real-time measurements remotely accessible to scientists and the general public — including fishermen and boaters — to help track water conditions.
One of the sensors the buoy is equipped with is called a YSI 6600 water quality sonde, an instrument consisting of several probes to measure various water quality parameters, including how much blue-green algae are present, water temperature, clarity, oxygen levels, turbidity and pH.
Founded in 1909, the U-M Biological Station is one of the nation’s largest and longest continuously operating field research stations. Laboratories, classrooms and cabins are tucked into more than 11,000 acres along Douglas Lake in northern Michigan to support long-term science research and education.
Subscribe to the UMBS monthly e-newsletter and follow the field station on LinkedIn, Instagram, Facebook and X (formerly Twitter).
