The excess carbonate helps maintain the neutral pH that was observed in all seasons. Biological activity clearly exerts a strong control on lake water chemistry. The striking inverse correlation between sdissolved oxygen and carbon dioxide supports this idea. Below the summer thermocline O2 is consumed and CO2 is generated by biological activity. This results in deeper portions of the lake becoming anoxic in the summer.
Pine Lake exhibits strong temperature stratification during spring and summer.
This stratification is important for lake chemistry. During the fall and very early spring the lake returns to a uniform temperature structure, resulting in effective mixing. Pine Lake contains levels of dissolved carbonate species in excess of that required by equilibrium with atmospheric carbon dioxide. This suggests that carbonate is the buffering agent that maintains the high pH of Pine Lake.