Transcript Ch. 22 The Water Planet

The Water Planet
Ch. 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
Ocean
Research
22.1
The use of submarines in World
War II advanced ocean research
with the invention of SONAR.
H.M.S Challenger
 1872 first large-scale ocean research
project
 Measured:
 Temperature
 Depth
 Took
water samples
 Observed 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-PairShare:
How do
humans
effect the
oceans?
List your ideas in your notes!!
Human Effects
 Oil spills
 Deep sea mining
 Magnesium
 Table
salt
 Pollution
 Dredging
 Disturbs
(Mg)
ocean floor
 Global warming
 Melts ice caps,
changes salinity & sea
level
Special
Properties
of Water
22.2
The density of water is greater than
its solid form, ice
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
Ocean
Water
22.3
Salinity and temperature are two
characteristics of water masses that
help scientists study oceans and their
behavior.
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
Variations in Salinity
LOW SALINITY AREAS
HIGH SALINITY AREAS
 near rivers where fresh
 hot, dry climates w/
water enters
 high precipitation near
equators
 sea ice melts
high evaporation rates

about 30º N & S (deserts)
 near poles as water
freezes
* 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!
Salt Enters & Leaves the Ocean
ENTER
LEAVE
 underwater volcanoes
 marine organisms use
 erosion from rocks
 marine organisms
decompose
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!
Temperature of the Ocean
 heat from sun
 temperature decreases
w/ depth
 Ocean divided into 3
temperature zones:
1.
2.
3.
Mixed Layer or
Epipelagic Zone
Thermocline
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
Page 8 INB:
 Little to no light
 Varies most at mid-
latitudes, not much
variation at poles or
Equator
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?
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.
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
Blooms are
visible
from space
and help
scientists
track life
forms.
Phytoplankton
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 Life
 no 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