Rapid pH changes, even within the range normally tolerated
by a species, may also cause the death of fishes1,6. Some liming
materials such as calcium oxide and calcium hydroxide can result
in a pH increase above 11, which is considered to be the alkaline
death point for pondfishes1
. However, these materials will react
with atmospheric carbon dioxide (CO2
) to form less hazardous
carbonates if applied to empty ponds several weeks before
refilling1
. This will prevent such excessive increases in pH
occurring from the use of these materials.
Ponds with substantial populations of phytoplankton or
aquatic plants may also experience wide diel fluctuations in pH.
This is caused by fluctuations in CO2
concentration due to
respiration and photosynthetic activity