Research buoys go into Flathead Lake

Researchers at The University of Montana’s Flathead Lake Biological Station (FLBS), in conjunction with Woods Hole Oceanographic Institution (WHOI), placed two large instrumental buoys in Flathead Lake on Aug. 10.

The buoys serve as a platform for monitoring instruments that provide continuous, automated measurements of water quality and meteorological conditions on Flathead Lake.

“With the automated equipment, we get data every five minutes,” said Bonnie Ellis, a research assistant professor at the station. “The advantage (of continuous data) is that we get a much higher resolution in terms of time series. In the past when we did research on the lake and the rivers, we had to travel by boat or by vehicle, and due to the cost of that we could only take samples about 15 times a year.”

The buoys were placed at two locations along the deep trench in the middle of the lake — one west of Yellow Bay and the other west of Woods Bay.

Each buoy contains two separate monitoring systems. One — a device called a profiler — contains sensors that measure conditions in the water column as the unit travels up and down a cable that is anchored at the bottom of the lake.

The profiler makes at least four trips to and from the bottom of the lake each day, measuring and recording water temperature, dissolved oxygen, conductivity, algal pigments, light and dissolved organic matter every 25 centimeters of depth.

That unit, which is powered by a small motor, transmits data through an attached wire as it covers the approximately 270 feet between the surface and the anchor. The data is then sent back to the biological station and WHOI via satellite.

“It’s really very new and cutting-edge,” Ellis said of the profiler.

The other system, which contains sensors that are mounted on top of the buoys, measures meteorological factors such as temperature, humidity, barometric pressure and wind speed and direction.

“Wind is really important in determining mixing in lakes,” Ellis said. “With increasing wind, you end up with different layers and stratification, which has an important effect on the biology of the lake.”

Since different organisms prefer to live in different levels of the water column, the mixing of water layers can lead to changes in a species’ ability to survive.

“It (mixing) can have consequences in which species has an advantage over another,” Ellis said.

Those changes can affect the food web, which in turn impacts the water quality of the lake.

According to Ellis, having immediate access to real-time water quality information gives researchers a huge advantage.

“We can produce better models that can be used to predict water quality changes,” Ellis said.

WHOI originally designed the monitoring systems for use in the Arctic Ocean, but worked with FLBS to modify them for use in Flathead Lake. The project was funded by a grant from the National Science Foundation.

“One of the neatest and most satisfying things has been the collaboration with Woods Hole because they are very interested in improving this profiling system,” Ellis said.

With the funding supplied by the grant, the systems will remain operational for about two years. At that point, FLBS will need to secure another grant to keep the project running.

Eventually, real-time data from the monitoring devices will be available to the public on the FLBS website, which can be found at http://umt.edu/flbs.

Using the Web page, boaters planning open-water travel can access mid-lake weather conditions collected by the meteorological sensors on the buoys. Fishermen will have access to temperature changes throughout the water column, allowing them to concentrate on fishing particular thermal regions. Federal, state, county and tribal agencies, as well as local schools, will also be able to use the wide array of water quality information.

Boaters are asked to stay at least 50 yards away from the buoys so as to not disturb the measurements or destroy the sensitive equipment. Video surveillance for security purposes will be present on both buoys.

For more information on the monitoring system, call FLBS at 982-3301.