Metabolism Autotrophs such as plants can construct the complex organic molecules in cells such as polysaccharides and proteins from simple molecules like carbon dioxide and water. Heterotrophs, on the other hand, require a source of more complex substances, such as monosaccharides and amino acids, to produce these complex molecules. Organisms can be further classified by ultimate source of their energy: photoautotrophs and photoheterotrophs obtain energy from light, whereas chemoautotrophs and chemoheterotrophs obtain energy from inorganic oxidation reactions. Photosynthesis is the synthesis of carbohydrates from sunlight and carbon dioxide (CO). In plants, cyanobacteria and algae, oxygenic photosynthesis splits water, with oxygen produced
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