Chapter 8 sec 1 Ocean Waters’ Durham Science

How did Earth Get Its Oceans? At one point scientist think Earth was hot rock w/out a trace of water. volcano gases & ash formed atmosphere! Earth cooled & water vapor _condensed ! Water came from 2 sources: 1. bombardment by comets X 2. gases (ammonia, water vapor, carbon dioxide) in atmosphere which came from volcanic activity! Water stayed in gaseous form until the surface____ cooled. Today there are five oceans: Atlantic, Pacific, Artic, Indian, Southern.

-Most abundant solid is Sodium Chloride (NaCl or SALT) -A measure of the amount of solids in a given amount of liquid is called __Salinity______________ (measured in grams of dissolved solids per killograms of water

How did the oceans get salty? River and streams are running water that carries dissolved minerals on land to oceans. Evaportion of ocean water leaves solids behind (chlorine, sodium, magnesium, sulfur, potassium, & calcium). In short oceans get their salinity because of evaporation. When the ocean evaporates on the water is evaporated. The solids are left behind. Since sodium chloride is the most abundant solid left by this evaporation it makes the oceans salty. So if you had 1000 grams of ocean water: 35 grams would be made up of salt (NaCl) and _965____ grams would be fresh water. Thus the ratio would be 35g or 7g 965g 193g

What effects salinity? Salinity: is the measure of the amount of dissolved salts in a given amount of liquids. 1. Climate affects salinity- Coastal waters with hotter more humid places have higher salinity because more evaporation is taking place. Coastal waters with cooler less humid places have lower salinity because less_ evaporation is taking place.   2. Water movement affects salinity- Places where there is no moving water such as bays, gulfs, and seas have higher salinity. Why? Because of evaporation and no new current bringing in new water. In short salinity varies in different parts of the ocean because of variations (differences) in evaporation, circulation, and freshwater inflow.

Ocean’s Temperature Zones The temperature of the Ocean _decreases______ as depth increases. There are three main temperature zones: Surface zone Thermocline Deep zone

Surface Zone Surface Zone- The warm top layer of the ocean water. It can extend 300 m below sea level. Sunlight heats the top 100 m of the surface zone and the surface currents mix the heated water with the other 200m of ocean water below.

Thermocline Second layer of ocean water. It can extend from 300m below sea level to about 700 m below sea level. In this zone temperature drops faster with increased depth than the other two zones.

Deep Zone Deep zones- Bottom layer of the ocean water that extends from the base of the thermocline to the bottom of the ocean. It is really cold down here with temperature ranges from 1oC to 3oC

The ocean plays a big part in keeping Earth suitable for life. Big bodies of water can absorb and hold energy from sunlight. Water releases thermal energy much slower than land. If it were not for the Earth’s oceans the temperatures would vary greatly from day to night as much as 100 degrees. This would not do. Thus the ocean regulates the temperature on land. Due to ocean currents this allows for warm water to keep to keep certain parts of the world warmer than what they otherwise would be. For instance Britain would be a lot colder in the winter time if it were not for the warm water from the Gulf stream.