Earths Oceans https www youtube comwatch v3 GRA

Earth’s Oceans https: //www. youtube. com/watch? v=3 GRA 7 il. M 708 Divisions Dissolved Solids Dissolved Gases Upwelling

Freshwater n 3% of Earth’s water n n n Minerals from rocks and pollutants from air get mixed in n Density = 1. 0 g/cm 3 Freezes at 0ºC n n Seawater 97% of Earth’s water Mixture of substances not just pure H 2 O n n 2% in glaciers 1% lakes, rivers, & aquifers vs. 96. 5% water and 3. 5% dissolved salts Na. Cl is most abundant salt Dissolved gases include O, N, CO 2 Salinity varies from place to place Density = 1. 02 -1. 03 g/cm 3 Freezes at -2ºC

Both Fresh and Seawater n Respond to solar radiation (sunlight) n remember it is the sun that drives the water cycle

Visible Light n Visible light is both absorbed and reflected Most wavelengths are absorbed n Blue light is reflected n n All wavelengths are absorbed by 100 m depth so deep lakes and oceans are dark except for surface

Absorption of Light – Water absorbs light, which gives rise to another physical property of oceans—they are dark. – In general, light penetrates only the upper 100 m of seawater. – Light sufficient for photosynthesis exists only in the top 100 m of the ocean.

Infrared Rays n n n Determine water temperature Rapidly moving water does not have time to absorb infrared waves Lakes and ponds become warm because absorb infrared rays Upper zone of ocean absorbs infrared so only surface is heated Surface temperature varies with latitude Deep seawater is very cold

How Did the Oceans Form? n About 4. 5 billion years ago, there were no oceans. n Sometime before 4 billion years ago, water vapor in the atmosphere condensed and fell as rain. n The rain filled the deeper levels of Earth’s surface and the first oceans began to form. https: //www. youtube. com/watch? v=Po. V 4 q. Swg 7 nc

The Global Ocean Ø Ø All waterways on earth are connected to the oceans because almost all watersheds empty into the ocean. Minerals and gases are carried along with the water and dissolve into seawater

The Global Ocean Ø Oceans produce most of the earth’s rain and oxygen (over 50%) Ø The ocean affects every person on Earth

Divisions of the Global Ocean ≈ Pacific Ocean – largest (North and South) ≈ Atlantic Ocean - half the volume of Pacific (North and South) ≈Indian Ocean - 3 rd largest ≈Southern Ocean-Newest recognized in 2000 ≈Arctic Ocean – smallest with most covered in ice

Divisions of Ocean All five of Earth’s oceans are connected to each other by the ocean currents creating 1 global ocean https: //www. youtube. com/watch? v=vy 6 dj_ZWOos

Earth’s Oceans

Ocean water contains salt n Ocean water is 96. 5% water n n Plus, ions of dissolved salts Evaporation removes pure water n Leaving salt behind Low levels of nutrients (nitrogen and phosphorus) n Oxygen is added by n

Ocean water is vertically structured n Temperature declines with depth n Heavier (colder, saltier) water sinks n n Light (warmer, less salty) water stays near the surface Temperatures are more stable than land temperatures Water has high heat capacity (heat required to increase temperature by a given amount) n It takes more energy to warm water than air n n Oceans regulate Earth’s climate n They absorb and release heat

What’s in Ocean Water? n Oceans contain many dissolved solids and gases. n Dissolved solids like minerals and salts are eroded from the land as rivers travel to the sea. n When the water evaporates, these minerals are left behind. This is why the ocean is salty. n Some gases become dissolved in the ocean through wave action. Others come

Characteristics of Ocean Water n Dissolved solids: Sodium chloride, or table salt, is the most abundant dissolved solid in the ocean. Other solids are also found in ocean water.

Salinity https: //www. youtube. com/watch? v=EIDSMz. XXz. LM Amount of dissolved salts present in a sample of ocean water n Described in parts per thousand n n ppm this is the notation for parts per thousand Changes in Salinity Climate and water movement affect salinity. Costal water in cool, humid places has a low salinity. Slow-moving bodies of water have higher salinity than other parts of the ocean do. n Salinity in various regions all differ n n Range from 33 ppm to 40 ppm

Characteristics of Ocean Water n Dissolved Gases Nitrogen, oxygen, and carbon dioxide are the main gases dissolved in ocean water. n More than half of Earth’s oxygen comes from the surface layers of the ocean. n About 93% of the world’s carbon dioxide is dissolved in the ocean.

CO 2 n. Has more than 60 times that is the atmosphere n. Called carbon sink can trap CO 2 for thousands of years

Dissolved Gases In Ocean 1. 41. 6 0. 1 Nitrogen (N) 34. 3 62. 6

Behavior of Gases in Water n You know that warm water dissolves solids more easily than cold water. n Try to dissolve sugar in cold and warm water, and you’ll see that it’s true. n Gases behave in the opposite way. Cold water dissolves gases more easily than warm water. n Open a warm and a cold soda. The warm one will fizz more and go flat more quickly. n This is because the CO 2 dissolved in the

Behavior of Gases in Water n Pressure also plays a role in how easily gases dissolve in water. n If the water is under high pressure, gases dissolve more easily than water under no pressure. n To keep CO 2 dissolved in soda, it is bottled under pressure. When you open the soda, it loses pressure. The CO 2 fizzes out and the soda eventually goes flat.

Temperature Zones 25°C 23°C Surface Zone 0 m 300 m 5°C Thermocline 700 m 1°C Deep Zone to 1200 m

Temperature Zones ≈Sunlight heats the top 100 m of the surface zone ≈Surface currents mix the heated water with cooler water in surface zone

Surface Temperature Changes Two factors affect surface temperatures: ≈Latitude-water along equator is warmer because it receives more direct sunlight (So temp would be lowest at the poles. ) ≈Time of year-more direct sun during summer, so surface zone is heated more

n Oceans Ocean Currents don’t just sit still. n Currents move ocean water from place to place, moving nutrients and organisms with it. n One very important kind of ocean

Upwelling n Defined as the movement of deep, cold, nutrient rich water to the surface. n Because many nutrients sink to the bottom of the ocean, upwelling brings nutrients up where surface organisms can use them. n These nutrient rich waters near the surface create productive fisheries. n Let’s watch a video to see how this occurs: n n http: //www. classzone. com/books/earth_science/terc/content/visualization s/es 2405 page 01. cfm http: //www. youtube. com/watch? v=APMz. M-x. Yl. Os

Upwelling n Wind blows away from the shore, taking surface water with it. n Deep water “wells up” to replace the surface water. n This brings deep, cold, nutrient rich water up to the surface.