The researchers are using an autonomous underwater vehicle to measure slices of water quality. The slender, battery-powered vehicle is about 3 feet long and is programmed to trace specific routes in collecting data such as oxygen and chlorophyll concentrations, pH, and turbidity. Strings of sensors extending to the lake bottom from buoys also are recording temperature readings every 15 minutes.
The near-shore region is defined by waters up to a depth of 15 meters, which extends several miles in Lake Michigan because of the lake's gradually downsloping seabed.
"It's an incredibly dynamic part of the lake," Troy said. "You have rapid influxes of cold water, which can negatively impact the larval fish. Any time the wind direction changes, that affects where you get cold-water masses. Almost all of the motion in the Great Lakes is governed by the speed and the direction of the wind."
Other researchers have shown that the strength and direction of lake winds have shifted in recent decades.
"The idea is that if we can correlate larval fish growth and survival with wind patterns right now, and these correlations hold in the future, then we can use climate models to tell us how the wind will likely change and then speculate how fish might be affected in the future," Troy said. "It's too early to say whether we'll see more or fewer upwelling events, but the frequency of them is likely to change, and that will have an important effect on larval fish."
The Great Lakes are the largest surface freshwater resource in the world, providing drinking water to millions of U.S. and Canadian citizens, harboring habitats for birds and fish, and generating millions of dollars in regional commerce from recreation, shipping, commercial fisheries and water-dependent industries.
The researchers analyze structures called oto
|Contact: Emil Venere|