The water molecules pack together tighter as pressure increases-the pressure increase with depth, due to the weight of the water above, and causes the greatest density changes in seawater with depth (greater than the density changes due to temperature and salinity changes).eawater Properties that Control Density. Density is defined as the mass of water per unit volume and has units of grams per cubic centimeter (g /cm3), kilograms per liter (kg/ L) or kilograms per cubic meter (kg/m3). The density of fresh water at 4 C is 1.0000 g/cm3 or 1.000 kg/liter or 1000 kg/m3.
Answer Wiki. Swans live for approximately 20 to 30 years. Some variations exist between the more common swan species. The trumpeter swan, which is the largest swan in North America, lives for an average of 24 years in the wild but has been known to live for 33 years in captivity. A mute swan lives for an average of 19 to 20 years; the tundra swan has a similar life span.
(see Precious) âº Mating: Swans begin to breed between 3 and 4 years of age. It s a special treat to see swan mates displaying during the mating season, gracefully touching bill-to-bill and breast-to-breast until a perfect heart shape is formed, or gently intertwining their necks.