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.
Generally, black swans nest in the wetter winter months (February to September), occasionally in large colonies. A black swan nest is essentially a large heap or mound of reeds, grasses and weeds between 1 and 1.5 metres (3-4Â½ feet) in diameter and up to 1 metre high, in shallow water or on islands. mature black swan measures between 110 and 142 centimetres (43 and 56 in) in length and weighs 3.7â9 kilograms (8.2â19.8 lb). Its wing span is between 1.6 and 2 metres (5.2 and 6.6 ft). The neck is long (relatively the longest neck among the swans) and curved in an S-shape.