Introduction to the Oceans EES Unit 4.1

Fast Facts 71% of Earth’s surface is covered by water 97% of all water on Earth is contained in oceans

Functions of the Oceans Moderates climate Ranges from -70°C (-94°F) to 55°C (131°F), only 125°C (257°F) difference Mercury has a 610°C (1,130°F) range Average is 14.6°C (58.3°F) Average on Mars is -60°C (-80°F) Reason: water is able to hold a lot of heat

Major part of the water cycle (the biggest part) Most evaporation into clouds happens in the ocean Huge biodiversity Half of all species Most biomass on Earth Biomass: total mass of living organisms in a given area Over 50% of oxygen production (through plankton)

Oceanic Divisions Vertical divisions Photic zone: ocean zone in the top 200 meters of water that receives enough sunlight for photosynthesis to occur Aphotic zone: ocean zone deeper than 200 meters where too little sunlight penetrates for photosynthesis to occur

Horizontal divisions Intertidal (littoral) zone Ocean zone that is closest to shore, between the high and low tide marks Waves, tides, and currents operate here Neritic zone Ocean zone that lies over the continental shelf between the intertidal zone and the oceanic zone Light able to penetrate here Oceanic zone Ocean zone that consists of the open ocean farther from shore than the neritic zone Most sunlight does not penetrate

Ocean Water Salinity Where from? Concentration of dissolved salts in salt water Salts make up 3.5% of ocean water Most common is regular salt (NaCl), worth 86% of all salts Where from? Most come from weathered rocks carried by rivers

Salinity and Density Ocean is not uniform in temperature, salinity, currents, etc. Varies greatly with latitude Warm and saline near the tropics Colder and less saline near polar regions

As temperature increases, salinity increases Greatest density is where water is colder and more saline

Temperature and thermocline Temperature lowers the deeper you go A thermocline is the depth where the temperature drops very fast Makes a barrier for ocean life

Light at Depth Seawater does different things to different colors based on wavelength Cool colors (blue, green = short wavelength) are scattered Warm colors (red, yellow = long wavelength) are absorbed Very little light makes it down past 200m (about 600 feet)

The World’s Oceans Arctic Ocean Atlantic Ocean Indian Ocean Pacific Ocean Southern Ocean