2 Cool Facts 71% of all water on Earth is in our oceans. Average depth of the oceans is 2.65 miles deep!Deepest point in the ocean is about 7 miles deep!Pressure increases as you go down in the ocean.Until 2000, there were only 4 oceans.
3 Oceanography The study of Earth’s oceans Did not begin to study until 1800’s with the ChallengerChallenger: first research shipInvestigated ocean currents, temperature, and chemical composition of the ocean
4 Advanced Technology SONAR: SOund NAvigation and Ranging Submarines to investigate deep ocean trenches
5 Scientists use SONAR to map seafloor and NOW can use it to understand aquatic life!
6 Origin of OceansEarth’s water may have originated from Comets or through volcanism.Comets: carried water, collided with Earth, then released the waterVolcanoes: during eruptions, water vapor and carbon dioxide released, condensed, and formed Earth’s early atmosphere
7 The Major Oceans (5)PacificAtlanticIndianSouthernArctic
8 PacificLargestContains deepest point on earth! (7 miles deep-Marianas Trench)Covers ~35% of the EarthBetween Asia and NA/SA
9 Atlantic Next to NC! Deepest Point: Puerto Rico Trench Second largest Covers ~21% of Earth
10 Indian Deepest Point: Java Trench Near India-Africa on East and Asia on NorthCovers ~15% of Earth
11 Southern Ocean established in year 2000! Newest ocean Surrounds AntarcticaCovers the South Pole
12 Arctic Smallest ocean Deepest Point: Arctic Basin Covers North Pole Often completely frozen during the winter
13 Sea Level Level of the oceans’ surfaces Can change in response to the melting of ice during warm periods and/or expanding of glaciers during ice agesAverage sea level is rising at a rate of 1 to 2 millimeters per year because glaciers are melting (indicates a warm period)
14 Composition of Ocean Water 96.5% pure water and 3.5% saltsSalinity: total amount of solid material (salts) dissolved in waterSalinity measured in parts per thousand (ppt).
15 Where does the salt come from? Salt = NaCl = the salt you put on food!Comes from erosionSalinity can decrease by precipitation, runoff from land, melting of ice (all adding more freshwater)Salinity can be increased by evaporation (only the water evaporates, not the salt) and by sea water freezing (only the water freezes, not the salt)
16 Why are our oceans salty? Salinity affects density!We need changes in density so we can have ocean currents (we will study this in a few days)So what makes our water MORE dense? Less salt or More salt?
17 Profile of an OceanOcean water is warmer at the surface because of the sun.Temperature decreases with depth.Thermocline: zone in ocean where there is rapid temperature change.
18 Density and how it relates to temperature. Colder water is more dense…means it will be below warm water.Because of this, there are 3 zones:Surface zone: at topTransition zone: in middle (includes thermocline)Deep zone: at bottom. Sunlight never reaches this section. 80% of ocean water found here.
20 Ocean MovementsOcean water moves in 3 ways:WavesCurrentsTides
21 Waves The movement that carries energy through the water Most waves are caused by wind moving over the water’s surface.
22 Anatomy of a Wave Crest: top of the wave Trough: bottom of the wave Wave height: vertical distance between the trough and the crestWave length: horizontal distance between two crests or troughs.
23 Ocean CurrentsMasses of ocean water that flow from one place to another
24 2 types of currentsDensity currents: vertical currents that result from different densities of water. Denser water sinks.Surface currents: movements of water that flow horizontally in the upper part of the oceans surface-usually because of wind.
25 What ultimately fuels the currents? THE SUNWarms waters on surface-makes them less denseCauses evaporation-makes water more salty and therefore more dense
26 Tides Periodic rise and fall of sea level Caused by gravitational attraction between the earth and moon.Side of the earth facing the moon and opposite the moon experience tides.Usually 2 high and 2 low tides a day
27 Spring TideWhen the earth, moon, and sun are all lined up. This creates higher, high tides and lower, low tides. Occurs at full and new moons.
28 Neap TideDuring a first or third quarter moon, when the moon is at a right angle to the earth. Results in lower, high tides and higher, low tides.
29 Tidal rangeDifference in height between successive high and low tides.If high tide is 4 meters and low tide is 1 meter, what is the tidal range?
30 Tidal PatternsDiurnal tides: a single high tide and a single low tide each daySemidiurnal tides: two high tides and two low tides each dayMixed tides: two high and two low a day but the the heights are different between the two high and two low