Fractionation of carbon isotopes in oxygenic photosynthesis characterization of food chains. Oxygenic photosynthesis is a metabolic pathway facilitated by autotrophs, including plants, algae, and cyanobacteria. This pathway converts inorganic carbon dioxide from the atmosphere or aquatic environment into carbohydrates, using water and energy from light, then releases molecular oxygen as a product. Organic carbon contains less of the stable isotope Carbon-13, or C, relative to the initial inorganic carbon from the atmosphere or water because photosynthetic carbon fixation involves several fractionating reactions with kinetic isotope effects. These reactions undergo a kinetic isotope effect because they are limited by overcoming an activation energy barrier. The lighter isotope has
Ocean storage of carbon dioxide has already gone into the oceans. Carbon dioxide is currently emitted at 10 GtC per year and the oceans currently absorb 2.4 Gt carbon dioxide per year. The ocean is an enormous carbon sink with the capacity to hold thousands more gigatons (Gt) of carbon dioxide. Ocean sequestration has the potential to decrease atmospheric carbon dioxide concentrations according to some scientists. After atmospheric carbon dioxide dissolves into the ocean, the aqueous carbon dioxide reacts with seawater to form carbonic acid. As carbonic acid continues to interact with water molecules, carbonate is formed, which increases the concentration of hydrogen ions in