L1 /
5
CH3041
ALKALINITY III
• The major basic
ions present in natural
waters are HCO3-, CO32-, OH- .
waters are HCO3-, CO32-, OH- .
Concentration
dependence
• acidic pH H2CO3 = “CO2”
• slightly acidic H2CO3, HCO3-
• slightly
basic HCO3-, CO32-
• basic
pH CO32-, OH-
•The alkalinity serves as
a
reservoir for inorganic carbon and thus as an indicator of the ability of the water to support biota – it is also a buffer system.
reservoir for inorganic carbon and thus as an indicator of the ability of the water to support biota – it is also a buffer system.
• As Dissolved Inorganic Carbon (pH7 HCO3-)
is used up a water will become more basic.
is used up a water will become more basic.
• Eventually the
water becomes too basic &
algal biomass production stops.
algal biomass production stops.
Species Distribution Diagram
