Oceanography







=[|Water - Density and Specific Weight]=

Density and specific weight of water at temperatures ranging //0 - 100 oC (32 - 212 oF)// - Imperial and SI Units
At aprox. //4oC (39.2oF)// pure water has it's highest density (weight or mass):
 * //1 g/cm3 = 1 g/ml = 1 kg/litre = 1000 kg/m3 = 1 tonne/m3 = 62.4 lb/ft3 = 8.34 lb/gallon//.

Densities and Specific Weight of Water in Imperial Units
- //t -// //(oF)// || [|Density] - //ρ -// //(slugs/ft3)// |||| [|Specific Weight] - //γ -// ||
 * Temperature
 * ^  ||^   || //(lb/ft3)// || //(lb/US gallon)// ||
 * 32 || 1.940 || 62.42 || 8.3436 ||
 * 40 || 1.940 || 62.43 || 8.3451 ||
 * 50 || 1.940 || 62.41 || 8.3430 ||
 * 60 || 1.938 || 62.37 || 8.3378 ||
 * 70 || 1.936 || 62.30 || 8.3290 ||
 * 80 || 1.934 || 62.22 || 8.3176 ||
 * 90 || 1.931 || 62.11 || 8.3077 ||
 * 100 || 1.927 || 62 || 8.2877 ||
 * 120 || 1.918 || 61.71 || 8.2498 ||
 * 140 || 1.908 || 61.38 || 8.2048 ||
 * 160 || 1.896 || 61 || 8.1537 ||
 * 180 || 1.883 || 60.58 || 8.0969 ||
 * 200 || 1.869 || 60.12 || 8.0351 ||
 * 212 || 1.860 || 59.83 || 7.9957 ||







Ocean Food Webs and Chains















 * ~ Water salinity ||
 * ~ [|Fresh water] ||~ [|Brackish water] ||~ [|Saline water] ||~ [|Brine] ||
 * ~ < 0.05 % ||~ 0.05 – 3 % ||~ 3 – 5 % ||~ > 5 % ||
 * ~ < 0.5 ‰ ||~ 0.5 – 30 ‰ ||~ 30 – 50 ‰ ||~ > 50 ‰ ||

How are large animals affected by salanity?
===**Many marine organisms are highly affected by changes in salinity.** This is because of a process called osmosis which is the ability of water to move in and out of living cells, in response to a concentration of a dissolved material, until an equilibrium is reached. In general the dissolved material does not easily cross the cell membrane so the water flows by osmosis to form an equilibrium. Marine organisms respond to this as either being osmotic conformers (also called poikilosmotic) or osmotic regulators (or homeosmotic).===

How does the ocean become salty?
===When the earth formed, those minerals from which it was made that are readily soluble (such as sodium chloride - salt, but also other minerals) in water dissolved into the water found on the planet. This water filled the lowest depressions to make the oceans and these oceans were and are salty.===

What factors affect salanity of the ocean?




Salinity is often measured by measuring how well electricity travels through the water. This property of water is called conductivity. Water that has dissolved salt in it will conduct electricity better than water with no dissolved salt. The more salt that is dissolved in the water, the better the water conducts electricity. The salt content of the water can be measured very precisely using the conductivity method. Salinity can also be measured with a hand held refractometer. A refractometer measures the change of direction or bending of the light as it passes from air to water. Light moves slower in water than air. The more salt in the water, the slower the light moves. You can see the effect of light bending (refracting) as it passes from the water into the air by placing a pencil in a glass of water.

The pencil appears to bend where it enters the water. The pencil is not really bent. The light we see has bent as it moves from water to air. A refractometer is the best choice for measuring salinity when only approximate values are needed. Refractometers are easy to use in the field and relatively inexpensive


 * Method of Salinity Measurement || [[image:http://omp.gso.uri.edu/ompweb/doee/img/inv.gif width="1" height="1" align="center"]] || Precision ||
 * [[image:http://omp.gso.uri.edu/ompweb/doee/img/inv.gif width="1" height="1" align="center"]] ||
 * Hand-held refractometer || [[image:http://omp.gso.uri.edu/ompweb/doee/img/inv.gif width="1" height="1" align="center"]] || 1 part in 70 ||
 * [[image:http://omp.gso.uri.edu/ompweb/doee/img/inv.gif width="1" height="1" align="center"]] ||
 * Laboratory titration || [[image:http://omp.gso.uri.edu/ompweb/doee/img/inv.gif width="1" height="1" align="center"]] || 1 part in 350 ||
 * [[image:http://omp.gso.uri.edu/ompweb/doee/img/inv.gif width="1" height="1" align="center"]] ||
 * Modern salinometer (conductivity) || [[image:http://omp.gso.uri.edu/ompweb/doee/img/inv.gif width="1" height="1" align="center"]] || 1 part in 40,000 ||