text: The<unk>  (CT, or<unk>  or Dissolved<unk><unk>  (DIC) is the sum of<unk><unk>  species in a solution.  The<unk><unk>  species include<unk>  dioxide,<unk> ic acid, bicarbonate anion, and<unk> ate anion.  It is customary to express<unk>  dioxide and<unk> ic acid simultaneously as CO2* .  CT is an important parameter when making measurements related to the pH of natural aqueous systems, and<unk>  dioxide flux estimates.
  where,
  CT is the<unk> 
  [CO2*]  is the sum of<unk>  dioxide and<unk> ic acid concentrations  ( [CO2*] = [CO2] + [H2CO3])
  [HCO3−] is the bicarbonate concentration
  [CO32−] is the<unk> ate concentration
  Each of these species are intimately related by the following pH driven chemical equilibria:<unk>  is measured by the acidification of the sample which drives the equilibria to CO2.  This gas is then sparged from solution and trapped, and the quantity trapped is then measured, typically by infrared spectroscopy.
option_0: Total inorganic carbon
option_1: Uric acid
option_2: Ammonia
option_3: Albumin
option_4: Phosphorous acid
option_5: Phosphate
option_6: Osmolarity
option_7: Phosphonic acid