A Dynamic Water Body

Epilimnion
This top layer receives the most sunlight, warmth, and oxygen. Zebra mussels are common in this area, because their shell shape and byssal thread production let them attach firmly to hard surfaces and endure the motion of wind and waves.
Metalimnion
In this middle layer, cooler water mixes upward, and warmer water mixes downward. The thermocline—the point delineating the greatest temperature and density difference—resides here, moving up and down as the seasons and water temperatures change. In Hyde’s Quarry, the contractor injected potassium chloride directly into the lower layers after the thermocline initially blocked it from diffusing through the water column.
Hypolimnion
This bottom layer holds the coldest, darkest, most dense water. With low dissolved oxygen, it can become anoxic when the water body stratifies strongly in summer. Unlike zebra mussels, which prefer to attach to hard substrate, quaggas can settle in soft sediment here.