Post on 08-Apr-2018
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Andrew Bullen and Colin Bursey
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` How temperature affects water properties
` Stratification and thermoclines
` Surface temp patterns
` How currents and temperature interplay` References
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` Water can occupy either of its three physical
states depending mainly on its temperature.
Solid (Ice)
Liquid (Water as we generally think of it)
Gas (Steam orWater vapour)
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The temperature and density of water are inversely
proportional. This means that as the temperature
of the water decreases the density of the water
increases correspondingly.As the water molecules lose thermal energy they
become less excited and more tightly packed. This
increases density.
Fresh Water is most dense at 4C. Solutes changedensity and salt water is thus different.
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The ability of water to hold dissolved substances
decreases as its temperature increases. These
properties are also inversely proportional.
This decreased tolerance of solutes is due to
greater spacing of the water molecules as they
gain kinetic energy. The molecular interactions
between water and the solute are dramaticallyweakened.
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Decreasing Temperature Increasing Temperature
` Decrease density` Decrease solubility
` Increase density` Increase solubility
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` Changes in density caused by temperature
differences can cause sharp divisions between
layers of water.
` The different layers are separated by bordersknown as thermoclines.
` Denser cold water forms the bottom layer while
warmer water floats on top of the cold to form the
upper layer. There may be no layers at all ormultiple layers depending on local conditions.
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Image courtesy of Water on the Web
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` Latitude has a strong correlation to surface
temperatures due to varying insolation at differing
latitudes.
` The angle of the sun to the earth and its tiltedrotational axis cause solar energy input to vary
seasonally however areas closer to the equator
generally receive more solar energy then areas
closer to the poles.` Therefore surface temperatures are generally
higher at lower latitudes.
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` Tropics and subtropics often >25C
` Polar regions often near or < 0C
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` When a deep water cold current meets a land
mass (sea mount, continent, ect.) the cold water is
forced upwards. This upwelling is often nutrient
rich and provides the food base for many strongfisheries
` As warm surface currents head north they cool
and the water sinks. This is known as downwelling.
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Pinet, Paul R. (2009) Invitation to Oceanography, 5th
edition. Jones and Bartlett, Sudbury, MA.
Castro, Peter, and Huber Michael E. (2003) Marine
Biology, 4th edition. Mcgraw Hill, New York, NY