Oxygen releases oxygen into the atmosphere, while respiration, decay, and combustion remove it from the atmosphere. In the present equilibrium, production and consumption occur at the same rate. Free oxygen also occurs in solution in the world's water bodies. The increased solubility of at lower temperatures (see Physical properties) has important implications for ocean life, as polar oceans support a much higher density of life due to their higher oxygen content. Water polluted with plant nutrients such as nitrates or phosphates may stimulate growth of algae by a process called eutrophication and the decay of these organisms and other biomaterials may
Plant to plant communication via mycorrhizal networks be related; therefore, kin selection might improve inclusive fitness and explain why a plant might support a fungus that helps other plants to acquire nutrients. Receipt of defensive signals or cues from an infested plant would be adaptive, as the receiving plant would be able to prime its own defenses in advance of an attack by herbivores. Allelopathic chemicals transferred via CMNs could also affect which plants are selected for survival by limiting the growth of competitors through a reduction of their access to nutrients and light. Therefore, transfer of the different classes of infochemicals might prove adaptive for plants.