The Water PlanetCh. 22

What is Oceanography?

the study of the Earth’s oceans using chemistry, biology, geology, and physics.

Oceans cover 70% of the Earth’s surface

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

Ocean

Research

22.1

H.M.S Challenger

1872 first large-scale ocean research project

Measured:TemperatureDepthTook water samplesObserved currents

World War II

Better ocean maps and charts

Instruments: Sonar Magnetic recorders

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

Think-Pair-Share:How do humans

effect the oceans?

List your ideas in your notes!!

Human EffectsOil spillsDeep sea mining

Magnesium (Mg) Table salt

PollutionDredging

Disturbs ocean floorGlobal warming

Melts ice caps, changes salinity & sea level

The density of water is greater than its solid form, ice

Special Properties of Water

22.2

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!!!

Aqueous Solutions

ocean is best example!

as salt increases, density increases

change water’s: pH density boiling & freezing points

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

Ocean Water

22.3

Composition of Seawater

Contains salts as dissolved ions

85% sodium chloride ions

more than 70 elements some elements, such as

calcium (Ca)--needed for marine life shells

Ions in Seawater

Chloride 55.04%

Sodium 30.61%

Sulfate 7.68%

Magnesium

3.69%

All others 2.98%

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

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

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

Variations in Salinity

* SALINITY IS USUALLY AVERAGE (35‰) NEAR THE BOTTOM

High-5 & Share:What do you think the salinity

of the ocean is like at the Equator? Why?!

High-5 & Share:What do you think the salinity

of the ocean is like at the Poles? Why?!

At your seat…

Complete the bottom of p. 6 in

your INB.

Make a key for high or low salinity and

use 2 colored pencils. Ask for help

if you need it!

ENTER LEAVEunderwater

volcanoes

erosion from rocks

marine organisms decompose

marine organisms use minerals for life

precipitate out of solution into sediment at floor

Salt Enters & Leaves the Ocean

* Scientists believe the salinity of the ocean hasn’t changed in over 200 million years!

Temperature of the Ocean

heat from sun

temperature decreases w/ depth

Ocean divided into 3 temperature zones:1. Mixed Layer or

Epipelagic Zone2. Thermocline3. Deep zone

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 50-100m 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

Creation of the Mixed Layer (surface)

Thermocline

Temperature decreases rapidly throughout this zone

Little to no light

Varies most at mid-latitudes, not much variation at poles or Equator

    

Page 8 INB:

Which one belongs to the poles? The Equator? The mid-latitudes?• Talk with your neighbors!!!

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 temperature @ bottom = ~ 2° C

Water Mass

Characterized based on where they originate

Body of water characterized by: Salinity temperature

What do YOU think??

How do water

masses layer in the

ocean? Why?

Life forms range from microscopic organisms to the largest known animal, the blue whale.

Ocean Life

22.4

Scientists estimate that the oceans harbor as many as 10 million species!

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

Phytoplankton

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

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

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

Deep Ocean Lifeno photosynthesis means

no oxygen so CO2 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