What is the primary reason for the dramatic fluctuations in Lake Ontario's water levels?

The primary reason for the dramatic fluctuations in Lake Ontario's water levels is seasonal weather changes. Throughout the year, various climatic conditions can lead to significant variations in precipitation and evaporation rates, which directly impact the lake's water levels. During spring and early summer, increased rainfall and snowmelt contribute to rising water levels, while warmer temperatures in late summer and fall can lead to increased evaporation, resulting in lower levels.

In contrast, while industrial discharge, melting glaciers, and invasive species can certainly affect the overall ecosystem and health of Lake Ontario, they do not play a direct or primary role in the dramatic fluctuations of water levels as seasonal weather changes do. Understanding the impact of seasonal weather patterns helps in managing water levels and predicting changes throughout the year effectively.