K+/Na+ Ratio – Constant of Living and Non-Living Nature

A summary of literature data and the published results of our research show that in natural water bodies of the Earth – freshwater reservoirs (Lake Baikal, the Volga River), and lakes and seas with varying salinity (Lake Balkhash, the Caspian Sea, the Black Sea, the White Sea, the Barents Sea, and the Sea of Japan) – an increase in Na⁺ concentration from 0.18 mmol/L to 468 mmol/L is accompanied by an increase in K⁺ concentration from 0.025 mmol/L to 11.5 mmol/L (R² = 0.986, p < 0.001). In the internal fluids (blood serum, hemolymph) of hundreds of studied multicellular animal species – including mollusks, fish, amphibians, reptiles, birds, mammals, and humans – a similar pattern was observed: the K⁺/Na⁺ ratio remains constant, even as Na⁺ concentration increases from 15.9 mmol/L to 468 mmol/L and K⁺ concentration from 1.3 mmol/L to 15 mmol/L (R² = 0.832, p < 0.001). An almost complete match has been found between the K+/Na+ ratio constant in the internal fluids of living organisms and in the surrounding aquatic environment of the non-living nature. These findings indicate the constancy of the K⁺/Na⁺ ratio in the internal fluids of multicellular organisms and in the natural aquatic environments they inhabit. The revealed patterns are of fundamental importance for understanding the physiological principles of water-salt homeostasis. Deviations from standard physiological values of the K⁺/Na⁺ ratio are associated with various pathological conditions in humans.

K+/Na+ ratio, blood serum, hemolymph, homeostasis, water bodies of the Earth