YELLOW BAY – For 2 1/2 years, the big instrumented buoy – one of two in Flathead Lake – has been faithfully relaying mounds of data to scientists at the University of Montana’s Flathead Lake Biological Station here at Yellow Bay.
Early Tuesday morning, at about 6 a.m., it stopped.
Suddenly, the only instrument they were receiving data from was the Global Positioning System on board the buoy – and it was telling the UM folks that the buoy was suddenly off on a slow joy ride around the lake it was supposed to be monitoring.
“First it went north, and got close to the east shore,” says Bonnie Ellis, research assistant professor at the biological station. “It may have even beached there for a while. Then it headed back out into the lake, and went south into Skidoo Bay.”
Faculty and staff launched a rescue mission Wednesday, and located the buoy in front of a home on Blue Bay – right where the GPS said it was.
“I’m surprised no one called us,” Ellis says.
How it got loose from the cable that connected it to the bottom of the lake is a minor mystery.
Mysterious, at least, in that the buoy became disconnected from the cable in calm waters, and gently floated away.
There’s always a concern that an extremely inattentive boater might run into one of the two large buoys – the other is located west of Woods Bay – but boat traffic on Flathead is, shall we say, considerably less in January than July.
However, the buoy, which was placed a mile west of Yellow Bay in August 2011, was not damaged on its partial tour of Flathead.
“We had some incredible wind storms in the fall, one that blew over trees here at the biological station,” Ellis says. “I assume the cable sustained damage during those, because it was calm when it stopped relaying data.”
Among the data meteorological sensors on the buoy relayed back on Oct. 27 were wind speeds of up to 63 mph during storms that took down 300-year-old Ponderosa pines on Flathead’s east shore and knocked out power to thousands of people in northwest Montana.
The buoy itself may be undamaged, but Ellis has no idea what condition the profiler will be in.
The profiler is a device that travels up and down the cable at least four times a day, firing back information to the biological station approximately every 10 inches via satellite. The profiler measures everything from light to water temperature, acidity, turbidity, dissolved oxygen, conductivity, algal pigments and dissolved organic matter.
Now that they’ve got the buoy back – they towed it in to Yellow Bay Wednesday – the concern turns to the profiler, which Ellis says is on the bottom of Flathead Lake.
It’s equipped with an acoustic release mechanism that, when a signal is sent, should release the profiler so it can float to the surface.
“Is the profiler damaged?” Ellis says. “I don’t know.”
What she does know is there’s no money budgeted for recovering, repairing and redeploying a buoy.
“We don’t have the funds, and we’ll have to find some,” Ellis says. “It might have to sit all winter.”
The buoys were developed by the biological station and the Woods Hole Oceanographic Institution of Massachusetts, which designed similar buoys for use in the Arctic Ocean. The Arctic models were modified for scientific research in both Flathead Lake, and Crater Lake in Oregon.
A grant from the National Science Foundation provided the biological station with the original funding for its two buoys. The two in Flathead were placed in deep trenches in the lake.
“We’ll have to hire a barge, and a crane, and divers,” Ellis says. “We’ll need equipment to redeploy it, and we may have to fly out people from Woods Hole.”