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 Earth's climate. This presents itself as a readily available carbon sink to store and capture atmospheric carbon dioxide. Due to the solubility of carbon dioxide in water, CO2 naturally dissolves in oceanic waters to form an equilibrium. With an increase in the concentration of carbon dioxide in the atmosphere, the position of equilibrium pushes the equilibrium in the direction such that more CO2 dissolves into the water. Utilizing this mechanism, more than 500 Gtons of carbon dioxide (amounting to a total of 140 Gtons of carbon) of anthropogenic carbon dioxide emissions released over the past 2 centuries have been absorbed