Apparent Total CO₂ Equilibrium Point in Marine Algae during Photosynthesis in Sea Water

Abstract

A constant CO₂ equilibrium level was reached with marine algae in a closed container in sunlight in sea water. With an air atomosphere, values of 5 mg CO₂ per litre were maintained by Boodlea composita and by Halimeda cylindracea, and 2 mg per litre by Enteromorpha sp. These equilibrium values were increased in an atmosphere of 100% oxygen. These values may be comparable with compensation point analyses for land plants and are indicative of photorespiration in marine algae.