ES 4.6 PPT

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  • 1. 71% of Earths surface is covered with water. The global ocean is divided by the continents into 5 distinct, or sub-divisional, oceans: Pacific largest, flows between Asia and the Americas. Atlantic second largest, the volume of Pacific. Indian third largest. Arctic smallest, unique because surface is mainly ice. Southern extends from the coast of Antarctica to 60 south latitude.

2. All People Scream At Insects Atlantic Pacific Southern Arctic Indian 3. 300 MYA During Pangaea oceans formedone giant body of water calledPanthalassaPanthalassa. 200 MYA When Pangaea began to split, theNorth Atlantic Ocean and theIndian Ocean formed. Present Day Continents continue to move at arate of 1-10 cm/yr. The Pacific Ocean is actually gettingsmaller while all others are growing. 4. 4.5 BYA during Earthsformation, there were nooceans to be found. Volcanoes spewed lava, ash, andgases all over the place. Earth was cooling however, andabout 4 BYA, it cooled enough forwater vapor to condense. Water began falling as rain. Rain filled the depressions in Earths surface and the first oceans began formation. 5. The two main gases in theatmosphere areNitrogen, N2, andOxygen, 02. These two gases are alsothe main gases dissolved inocean water. While carbondioxide, CO2, is not a majorcomponent of theatmosphere, a large amountof this gas is dissolved inocean water. 6. Ocean water is 96.5% pure water, H20. Dissolved solids make up only about 3.5% of the mass of ocean water. These dissolved solids, commonly called sea salts, give ocean water its salty taste. Most salt in the oceans is the same salt we sprinkle on food, sodium chloride (NaCl). As rivers and streams flow towards the oceans, they carry dissolved minerals from the land. At the same time, water is evaporating from the ocean and leaving dissolved solids behind like salt! Dissolved solids in ocean include: Sodium (Na) Chlorine (Cl) Potassium (K) Calcium (Ca) Magnesium (Mg) Sulfur (S) Others 7. A measure of the amount of dissolved salts and other solids in a given amount of liquid is known as salinity. Usually measured as grams of dissolved solids PER gram (g) of water (or parts per thousand - ppt). Example: If 1000 g. of ocean water contained 35 g. of solids, the salinity of the sample would be 35 parts salt per 1000 parts ocean water (35 ppt).Increased precipitation Decreased salinity Increased evaporation Increased salinity Therefore, if you evaporated 1000 g.Increased winds Increased salinityof ocean water, 965 g. of freshwaterwould be removed and 35 g. of solidswould remain. 8. The temperature of ocean water decreases as depthincreases, but does not happen gradually. Divided into 3 layers (zones) based on temperature: Surface Zone the warm top layer of ocean water distributing heatdown-ward to a depth of 100 to 300 m. Surface currents mix theheated water with cooler waters below, therefore the temperature isrelatively constant. Thermocline the layer in a body of water in which watertemperatures drop with increased depth faster than it does in otherlayers. This layer exists because water near the surface becomes lessdense as energy from the sun warms the water. Deep Zone The bottom layer extending from the base of thethermocline to the bottom of the ocean. The temperature in thiszone is usually about 2 C. 9. SurfaceSurface Zone300 m.Thermocline700 m.Deep ZoneBottom 10. Surface temperatures of the ocean change dependent onlocation and season. Along equator warmer b/c they receive more direct sunlight per year thanareas close to poles. However, both hemispheres receive more direct sunlight per year than areasclose to the poles. Average surface temps: (image below) 11. The mass of a substance per unitvolume is called the density. Equation for density is: Density = mass volume For example, 1 cm3 of pure water has amass of 1 g. So the density of purewater is 1.0 g/cm3. The large amount of dissolved solids in oceanwater makes it denser than pure fresh water. Ocean water has a density between 1.020 g/cm3and 1.029 g/cm3. 12. Why is the ocean blue? The color of ocean water isdetermined by the way itabsorbs or reflects light. White light from the Suncontains light from all thevisible wavelengths of theelectromagnetic spectrum. Water absorbs most of thewavelengths, or colors, ofvisible light. Only the blue wavelengthstend to be reflected. 13. Sending people to severe depths of the ocean canbe dangerous so how can we study the oceanwithout doing this? Study from the surface of the ocean (ships). Study from high above in space. 2 main ways include: Sonar Satellites 14. SOund Navigation And Ranging Scientists send sound waves, orpulses, down from a ship. Sound waves moves through water,bounce off ocean floor, and return tothe ship. Deeper water = longer trips Depth calculated by multiplying half thetravel time by the speed of sound inwater (1500 m/s). The device used to measure this depth iscalled a fathometer. This creates a bathymetric profile: a mapof the ocean floor showing depth. 15. In the 1970s, scientists began studying the ocean floor viasatellite images (radar generated). 1978 the satellite Seasat was launched. Focused on the ocean, sending images back to Earth allowing scientiststo measure the direction and speed of ocean currents. 16. Geosat, once a top-secretmilitary satellite, has been usedto measure changes in theheight of the ocean surface. Mountains, trenches affectheight of the water above them. Use measurements to make a detailed map of the ocean floor. Maps made from satellite measurements can cover more territory than maps made using ship-based sonar readings. 17. Home to the worlds longest mountainchain, which is about 64,000 km. (40,000 miles). Canyons deeper than the Grand Canyon! Made of 2 major regions: Continental Margin made of continental crust. Deep Ocean Basin made of oceanic crust.Imagine the ocean as a giant swimming pool.Continental margin would be the shallow end.Deep ocean basin would be the deep end. 18. Continental Shelf: begins at shoreline and slopes gentlydown toward the open ocean. Continues until the ocean floor begins to slope more steeply downward. Continental Slope: begins at the edge of the continentalshelf. Continues down to the flattest part of the ocean floor. Continental Rise: the base of the continental slope, madeof large piles of sediment. Marks the boundary between the continental margin and the deep oceanbasin. Abyssal Plain: the broad, flat part of the deep-ocean basin. Covered by mud and the remains of tiny organisms. 19. Mid-Ocean Ridges: mountain chains forming at divergentplate boundaries (tensional force). Creates cracks, or rifts, in the ocean floor, where magma rises to fill thespaces. Rift Valley: a valley forming on the ocean floor in betweenmountains (mid-ocean ridges). Normally consist of magma being produced within. Trenches: huge cracks in the deep-ocean basin. Form where one oceanic plate is pushed beneath a continental plate oranother oceanic plate. Seamounts: individual mountains of volcanic material. Form where magma pushes its way through or between tectonic plates.If a seamount builds above sea level, it becomes a volcanic island. 20. 3 main groups of marine life: Plankton Free-floating microscopic organismsdrifting in the waters of aquaticenvironments. Phytoplankton plant like. Zooplankton animal like. Nekton Organisms swimming actively in theopen ocean. Whales, dolphins, sea lions, sharks, andother fish species. Benthos Organisms living on or in the bottom ofthe ocean. Crabs, starfish, worms, coral, sponges,seaweed, clams, oysters. 21. The ocean floor is divided intoecological zones based onwhere different organisms exist.The benthic zone is theThe pelagic zone is the bottom region of region of an ocean or oceans and bodies ofbody of fresh water fresh water. above the benthic zone. 22. Sublittoral zone Bathyl zone Hadal zone (in trenches) 23. The shallowest benthic zone, the intertidal zone, is locatedbetween the low-tide limits and high-tide limits. Twice a day this zone changes. As tide flows in, the zone is covered with ocean water. As tide flows out, the zone is exposed to air and sun. Intertidal organisms must be able to live both underwater and on exposedland (ex: crabs, oysters, clams) 24. The sublittoral zone is located on the continental shelf and iscontinuously submerged. Ends at the edge of the continental shelf, about 200 m. below sea level. More stable than the intertidal zone. Organisms always covered by ocean water (ex: coral, sea stars, and sea lillies). Temperature, water pressure, and amount of sunlight remain fairly constant. 25. The bathyl zone extends from the edge of thecontinental shelf to the abyssal plain. Depth range: 200 m. to 4000 m. below sea level. Lack of sunlight results in minimal plant life. Organisms include sponges, brachiopods, and octopuses. 26. No plants and few animals live in the abyssal zone, which ison the abyssal plain. Largest ecological zone of the ocean and can reach 6000 m. in depth. Common examples of species: sponges and tube worms. Organisms mentioned in previous zones can live in the abyssal zone suchas crabs and sponges. Organisms live around hot-water vents called black smokers. 27. The deepest benthic zone is the hadal zone. This zone consists of the floor of ocean trenches and any organismsfound there. Can reach from between 6000 m. to 7000 m. in depth. Scientists know very little about this zone and believe life there is sparse. However, a few types of sponges, clams, and other organisms have beenidentified within this zone. 28. The neritic zone is the ocean water covering thecontinental shelf. Warm, shallow zone with the largest concentration of marinelife mainly because of abundant sunlight. Fish, nekton, mammals (ex. dolphins), etc. Receives more sunlight than the other zones in the ocean. 2