Define limnology and differentiate the epilimnion, metalimnion, and hypolimnion.

• A. Limnology is the study of inland waters; epilimnion is the warm, upper layer; metalimnion (thermocline) is the transition zone; hypolimnion is the cold, deep layer.
• B. Limnology is the study of marine systems; epilimnion is the deepest layer; metalimnion is the warm surface; hypolimnion is the mid-depth layer.
• C. Limnology is the study of land ecosystems; epilimnion is the cool surface; metalimnion is the sediment layer; hypolimnion is the mid-depth layer.
• D. Limnology is the study of atmospheric layers; epilimnion is the upper air; metalimnion is the weather front; hypolimnion is none.

Answer: (A)