Peter Kallin talks to third graders as they head out Mill Stream toward Great Pond on Wednesday on board a boat in Belgrade.
Peter Kallin, left, Noah Easter and Cobey Dunn drop a net down to the bottom to see if they can catch plankton on Wednesday on board a boat on Great Pond in Belgrade.
Natasha Grass, left, lowers a Secchi disc as Elizabeth O'Donoghue looks into the water with an aqua scope on Wednesday on board a boat on Great Pond in Belgrade. The disc is lowered slowly down in the water and the depth at which the disc is no longer visible is taken as a measure of the transparency of the water.
Gloria Mrazik reacts after feeling the coldness of the water from the bottom of Great Pond on Wednesday on board a boat in Belgrade.
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