2Cool 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.
3Oceanography 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
4Advanced Technology SONAR: SOund NAvigation and Ranging Submarines to investigate deep ocean trenches
5Scientists use SONAR to map seafloor and NOW can use it to understand aquatic life!
6Origin 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
7The Major Oceans (5)PacificAtlanticIndianSouthernArctic
8PacificLargestContains deepest point on earth! (7 miles deep-Marianas Trench)Covers ~35% of the EarthBetween Asia and NA/SA
9Atlantic Next to NC! Deepest Point: Puerto Rico Trench Second largest Covers ~21% of Earth
10Indian Deepest Point: Java Trench Near India-Africa on East and Asia on NorthCovers ~15% of Earth
11Southern Ocean established in year 2000! Newest ocean Surrounds AntarcticaCovers the South Pole
12Arctic Smallest ocean Deepest Point: Arctic Basin Covers North Pole Often completely frozen during the winter
13Sea 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)
14Composition 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).
15Where 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)
16Why 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?
17Profile 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.
18Density 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.
20Ocean MovementsOcean water moves in 3 ways:WavesCurrentsTides
21Waves The movement that carries energy through the water Most waves are caused by wind moving over the water’s surface.
22Anatomy 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.
23Ocean CurrentsMasses of ocean water that flow from one place to another
242 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.
25What ultimately fuels the currents? THE SUNWarms waters on surface-makes them less denseCauses evaporation-makes water more salty and therefore more dense
26Tides 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
27Spring 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.
28Neap 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.
29Tidal 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?
30Tidal 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