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
Artificial uterus the United States. A human placenta may theoretically be transplanted inside an artificial uterus, but the passage of nutrients across this artificial uterus remains an unsolved issue. The main function of an "amniotic tank" would be to fill the function of the amniotic sac in physically protecting the embryo or fetus, optimally allowing it to move freely. It should also be able to maintain an optimal temperature. Lactated Ringer's solution can be used as a substitute for amniotic fluid. Theoretically, in case of premature removal of the fetus from the natural uterus, the natural umbilical cord could be used, kept