Earth's Circulatory System

 And the Spirit of God moved upon the face of the waters. 

Genesis 1:2

"Unlike almost all other substances, water expands and becomes less dense in its solid form than it is in its liquid form. Ice has an open

structure that is sustained by the hydrogen bonds between water molecules. If ice behaved like almost all other substances (a notable exception being the metal gallium, which also expands on freezing), it would sink to the bottom and the oceans would freeze from the bottom up, leading to much of our planet being permanently encased in ice — since the ice beneath the water would be shielded from the warmth of the sun’s rays. Since ice expands upon freezing, however, it insulates the water beneath the surface, keeping it in its liquid form. 

---This property of water is essential to complex life, both marine and terrestrial.

Water is also a nearly universal solvent, and this property is critical to its role in dissolving minerals from the rocks. Indeed, almost all known chemicals dissolve in water to at least some extent. The solubility of carbon dioxide in water and its reaction with water to yield carbonic acid also promotes chemical reactions with these minerals, increasing their solubility.

For life on land to thrive, the dissolved minerals also must be

deposited on land, which is made possible by the hydrological cycle whereby the water from the oceans evaporates into the atmosphere and returns to the ground as rain or snow. The hydrological cycle is itself made possible by water’s existence in three states (solid, liquid, and gas) in the range of ambient temperatures at the earth’s surface. This ability to exist in three different states at the ambient conditions at the earth’s surface is unique among all known substances. 

---Were it not for this unique property of water, the land masses of our planet would exist as a barren dessert. 

Michael Denton remarks concerning this remarkable property: 

“the delivery of water to the land is carried out by and depends upon the properties of water itself. Contrast this with our artifactual designs, where key commodities such as clothes or gasoline must be delivered by extraneous delivery systems such as trucks and trains. Gasoline cannot deliver itself to gas stations nor clothes to clothing stores. But water, by its own intrinsic properties, delivers itself to the land via the hydrological cycle.”

Various properties of water also make it an ideal medium for the

circulatory system of complex organisms like ourselves.
Another characteristic of water is that its viscosity is one of the lowest of any known fluid. The pressure that is needed to pump a fluid increases proportionally with its viscosity. Therefore, if the viscosity of water were significantly increased, it would become prohibitively difficult to pump the blood through the circulatory system. Denton notes that 

“the head of pressure at the arterial end of a human capillary is thirty-five mm Hg, which is considerable (about one-third that of the systolic pressure in the aorta). This relatively high pressure is necessary to force the blood through the capillaries. This would have to be increased massively if the viscosity of water were several times higher, and is self-evidently impossible and incommensurate with any sort of biological pump.”

Water, furthermore, has one of the highest specific heat capacities of any known fluid. By serving to retard the cooling rate, this property conserves water in its liquid form when it comes into contact with air that is below freezing temperature. 

Another remarkable feature of water is its evaporative cooling effect. As water evaporates from an object’s surface, the molecules with more kinetic energy escape as a gas, whereas those with lower kinetic energy remain in liquid form. This serves to reduce the surface temperature. The evaporative cooling effect of water is in fact higher than that of any other known molecular liquid — i.e., compounds composed of two or more types of atoms. This characteristic of water is particularly important for warm-blooded organisms when the external temperature is warmer than their core body temperature and thus the excess heat cannot be radiated out into the environment. Instead, excess heat is lost through the evaporative cooling effect of water, maximized by numerous sweat glands on the skin surface." 

EN&V