The Water Planet Ch. 22

Transcription

1 The Water Planet Ch. 22

2 What is Oceanography? the study of the Earth s oceans using chemistry, biology, geology, and physics. Oceans cover 70% of the Earth s surface

3 Ocean Research 22.1 The use of submarines in World War II advanced ocean research with the invention of SONAR.

4 H.M.S Challenger 1872 first large-scale ocean research project Measured: Temperature Depth Took water samples Observed currents

5 World War II Better ocean maps and charts Instruments: Sonar Magnetic recorders

6 Modern Research (Technology) Deep sea-corers take sediment samples Sonar measures ocean depth Deep sea cameras and lights, robotics, and advanced technology help explore the sea floor & take samples buoys & satellites radio data back SST, sea level, & mov mt

7 Think-Pair- Share: How do humans effect the oceans? List your ideas in your notes!!

8 Human Effects Oil spills Deep sea mining Magnesium (Mg) Table salt Pollution Dredging Disturbs ocean floor Global warming Melts ice caps, changes salinity & sea level

9 Special Properties of Water 22.2 The density of water is greater than its solid form, ice

10 Density Density= mass volume (g/cm³)- it s a ratio! Density of fresh water= 1.0 g/cm³ (above freezing) Density of ice= 0.92 g/cm³ Water expands as it freezes because of it s shape! ICE FLOATS!!!

11 Aqueous Solutions ocean is best example! when any salt dissolves in water as salt increases, density increases change water s: ph density boiling & freezing points

12 Ocean Water 22.3 Salinity and temperature are two characteristics of water masses that help scientists study oceans and their behavior.

13 Composition of Seawater Contains salts as dissolved ions Ions in Seawater Chloride 55.04% Sodium 30.61% 85% sodium chloride ions more than 70 elements some elements, such as calcium (Ca)--needed for marine life shells Sulfate 7.68% Magnesium 3.69% All others 2.98%

14 Salinity measure of dissolved salts in water units= parts per thousand ( ) Ex: 1000 grams of seawater contains 35 grams of salt= 35 measured w/ hydrometer

15 Salinity oceanographers calculate salinity by electrical conductivity of seawater The higher the salinity, the stronger the electrical current units= practical salinity units or psu average seawater = 35 psu Water Mass= body of water with distinct properties based on where it originates salinity values used to help identify these

16 Variations in Salinity LOW SALINITY AREAS HIGH SALINITY AREAS near rivers where fresh water enters high precipitation near equators sea ice melts hot, dry climates w/ high evaporation rates about 30º N & S (deserts) near poles as water freezes * SALINITY IS USUALLY AVERAGE (35 ) NEAR THE BOTTOM

17 Turn to the person next to you & Share: What do you think the salinity of the ocean is like at the Equator? Why?!

18 Turn to the person behind you & Share : What do you think the salinity of the ocean is like at the Poles? Why?!

19 Salt Enters & Leaves the Ocean ENTER underwater volcanoes erosion from rocks marine organisms decompose LEAVE marine organisms use minerals for life precipitate out of solution into sediment at floor * Scientists believe the salinity of the ocean hasn t changed in over 200 million years!

20 Temperature of the Ocean heat from sun temperature decreases w/ depth Ocean divided into 3 temperature zones: 1. Mixed Layer or Epipelagic Zone 2. Thermocline 3. Deep zone

21 Epipelagic Zone or Mixed Layer winds and currents mix heat evenly most life lives here; only zone for plants makes up 2% of ocean s volume can be m deep; in some spots 300m temperature depends on latitude and season; poles and equator mixed layer temperature is constant Most oxygen- b/c of atmosphere & organisms (photosynthesis) Oxygen decreases with depth

22 Creation of the Mixed Layer (surface)

23 Thermocline Temperature decreases rapidly throughout this zone Page 8 INB: Little to no light Varies most at midlatitudes, not much variation at poles or Equator Which one belongs to the poles? The Equator? The mid-latitudes? Talk with your neighbors!!!

24 Deep Zone No sunlight reaches seafloor- DARK! Very little oxygen & life Polar water masses are found at bottom because they are denser than other water and move around globe Seafloor bottom = ~ 2 C

25 Water Mass Characterized based on where they originate Body of water characterized by: Salinity temperature

26 What do YOU think?? How do water masses layer in the ocean? Why?

27 Ocean Life 22.4 Scientists estimate that the oceans harbor as many as 10 million species! Life forms range from microscopic organisms to the largest known animal, the blue whale.

28 Photosynthesis in the Ocean takes place within mixed layer Phytoplankton: microscopic single celled protists that float freely within ocean waters take CO2 out of water and replace with oxygen basis of food chain in ocean Diatoms are examples with silica shells; deposited on seafloor when they die Blooms- abundant phytoplankton populations; change color of seawater to green, yellow, or brown Visible from space; scientists use to locate groups of life forms

29 Blooms are visible from space and help scientists track life forms. Phytoplankton

30 Marine Animal Life Zooplankton: microscopic animals that eat phytoplankton or smaller zooplankton other animals eat zooplankton can be larvae of larger animals s.a. squid, crab, jellyfish moderate salinity by absorbing ions to make shells; back into water when they die promote nutrient circulation as waste falls to bottom Coral: tiny sea creatures that form reefs lime from ocean creates shells; when they die new ones grow on old ones prevent beach erosion b/c they stop waves along coasts provide nutrients and shelter for larger organisms

31 Marine Animal Life (cont.) Nektons: free-swimming organisms include fish, whales, jellyfish survival depends on temperature, salinity, and nutrient circulation important food supply for other nektons and humans overfishing, pollution, and trawling destroy populations & ecosystems

32 Deep Ocean Life no photosynthesis means no oxygen so CO 2 accumulates Hydrogen sulfide is primary source of energy spewed out of deep sea vents and smokers bacteria use chemosynthesis to produce food here chemosynthetic bacteria are food for larger organisms larger organisms thrive because of food & heat