Properties of the Ocean

I. Density The Density of water is affected by two things: A. Temperature 1. As water temperature decreases, density increases and volume increases. Once water becomes ice the density then decreases. Result: ice forms and floats B. Salinity 1. When salts dissolve in pure water, the water’s density increases Result: freshwater floats on saltwater.

II. Stratification A.Occurs when water masses with different properties form layers according to density. B. Types of stratifications 1.Thermocline-layering of water by temperature 2. Halocline-layering of water by salinity. 3. Pynocline- layer formed by a rapid change in water’s density due to changing temperature and salinity.

III. Where Does The Salt Come From? A. Degassing – the releasing of volatile chemicals after the Earth's formation and during volcanic activity (rained) B. Erosion - of sediments and basalts on land by weathering (Basalts-dark, heavy volcanic rocks that makes up most of the world's oceanic crust) C. Oceanic Crust – reactions in basalt releases chemicals into the seawater. This specimen was erupted from Kilauea volcano in 1960.

Where Does The Salt Come From? D. Biological Processes - produce organic chemicals and cycle bio-reactive elements E. Photochemical Reactions - occur in the upper pelagic waters (water not close to the bottom or near the shore) F. Radioactive Decay - elements forming other elements

A. Seawater contains almost every known natural element. 72 have been identified. B. Most abundant materials are chloride and sodium (seawater tastes like table salt – Sodium Chloride) IV. Composition of Saltwater ComponentConcentrationPercentage of Salinity chloride sodium sulfate magnesium calcium potassium bicarbonate0.140 C. Salt water is 96.5% H 2 O molecules

V. Measuring Salinity A. Specific Gravity 1. The specific gravity is a comparison of a substance’s density to that of water. 2. Written as a decimal. 3. The specific gravity of ocean water S.G. B. Parts Per Thousand 1. Measure of the amount of dissolved substance per thousand units of the other. 2. symbol used is o/ The salinity ocean water is 35 0/00

A. The variations in salinity are affected by the melting of ice, inflow of river water, evaporation, rain, snowfall, wind, wave motion, and ocean currents ( causing horizontal and vertical mixing of the saltwater.) B. The saltiest water (40 0/00) occurs in the Red Sea and the Persian Gulf, due to very high rates of evaporation. VI. Salinity Variations

C. The North Atlantic is the saltiest ocean; averaging about 37.9 o/oo. The saltiest part is the Sargasso Sea; created by floating brown seaweed called "sargassum". High temperatures equals a high rate of evaporation and the area receives no fresh-water inflow due to its location.

D. Low salinities occur in polar seas diluted by melting ice and rain. The Baltic Sea’s salinity is between 5 to 15 o/oo and the Black Sea is less than 20 o/oo. Puget Sound in the Tacoma, Wash.ranges from o/o0 due to fresh-water streams.