SOLVENT PROPERTY. Water can dissolve more substances than any other common liquid.
Bio. Significance. Ocean water carries dissolved within it the nutrients and oxygen required
by marine organisms. This has produced the "saltiness" of the ocean.
HEAT CAPACITY. The quanity of heat required to change the temperature of 1 gram of a
substance 1 Degree Celsius. Water has the highest heat capacity of all common liquids.
Bio. Significance. It is this property that makes water an important moderator of climate.
It accounts for the narrow range of temperature found at any location in the ocean. Because
water can gain or lose a tremendous amount of heat without changing its temperature it acts
as an insulator for marine life.
LATENT HEAT OF MELTING. The quantity of heat gained or lost per gram by a substance
changing from a solid to a liquid or from a liquid to a solid without a change in temperature.
The latent heat of melting for water is 80 cal, the highest of all common substances.
Bio. Significance. When ice forms, most of the heat energy lost is released to the
heat-deficient atmosphere. When ice melts, the energy gained by the water is manifested
as molecular energy of the liquid water. This prevents the high-latitude ocean from
becoming much warmer or colder than the freezing point of seawater.
LATENT HEAT OF VAPORIZATION. The quantity of heat gained or lost per gram
by a substance changing from a liquid to a gas or from a gas to a liquid without a change
in temperature.
Bio. Significance. A great amount of excess heat energy is removed from the low-latitude
ocean by evaporation and released through precipitation into the atmosphere at heat-deficient
higher latitudes. This property contributes greatly to the fact that the polar regions do not get
increasingly colder and the equatorial region does not get increasingly hotter.
SURFACE TENSION. Highest of all common liquids. Cohesive attraction of hydrogen
bonds causes a "skin" one molecule thick to form on a water surface and helps to make
capillarity possible.
Bio. Significance. Some organisms use this "skin" as a walking surface. Others hang
from its undersurface.
DENSITY. Mass per unit of volume. Density is increased by increasing salinity and
pressure and decreasing temperature.
Bio. Significance. Plankton that stays near the surface through buoyancy and frictional
resistance to sinking are greatly influenced by the effect of temperature on density.
In low-density warm water, plankton must be smaller or more ornate, thereby increasing
the ratio of surface area to unit of body mass, in order to reduce their rate of sinking.
