Transcript unit 1 powerpoint

Lesson 2:
Ocean Exploration
Social Science
TODAY WE WILL STUDY THE HISTORY OF OCEAN
EXPLORATION AND NAVIGATION
 Earth’s oceans
 A timeline of famous explorers and their discoveries
 The inventors of technology that innovated the way
we study the sea
 Terms and facts related to navigating the ocean
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EARTH’S OCEANS
 70% of Earth’s surface
 80% of Earth’s volcanic activity takes place underwater
 Dominate the surface area of the globe
 Oceans are interconnected
 The oceans contain 97.2% of all the water on or near Earth’s
surface
5 OCEANS
1. Pacific Ocean
 Largest and deepest ocean
2. Atlantic Ocean
 Second largest ocean
3. Indian Ocean
 Smaller than the Atlantic
 Exists mostly in the Southern Hemisphere
4. Arctic Ocean
 Smallest and shallowest ocean
5. Southern Ocean or Antarctic Ocean
 Defined by Antarctic convergence and surrounds Antarctica
SEA VS. OCEAN
 Seas are:
 smaller and shallower
 composed of salt water (Dead Sea; surrounded by land)
 partially enclosed by land (or encircled by ocean currents)
SEAFLOOR DEPTH
 Avg. depth of ocean is 3729 m
(12,234 ft)
 Deepest part of the ocean is the
Mariana Trench (11,022 m or
36,161 ft)
LAND ELEVATION
 Avg. elevation of land is 840 m
(2,756 ft)
 Highest land elevation is
Mt. Everest (8,850 m or 29,035 ft)
MAUNA KEA
 Mountain on the island of Hawaii has the greatest total height
from base to top
 4,206 m (13,800 ft) above sea level
 5,426 m (17,800 ft) from sea level down to its base
 Total height of 9,632 m (31,601 ft); 1,390 m (4,560 ft)
 Shorter than the Mariana Trench is deep
LATE BC – 1 BC
EARLY EXPLORATION
Late BC
4000-3000
2000-1000
Egyptian Voyages First Sea Routes
150
1 BC
Ptolemy’s Map
Photo: Library of Congress
The Polynesians
the first
known
The were
Greek
astronomer
Ptolemy
The earliest recorded sea
people to undertake
regular,
longmakes a map
of the
world and is one
voyage was undertaken by
distance voyages.
elaborate
of theThey
firstbuilt
known
to include latitude
ancient Egyptians around
canoes (like the
at left)
to carry
andreplicas
longitude
lines.
3200BC.
supplies and developed a navigational
system based
onmap
the at
position
the
The
left is aofrepresentation
stars. by the Library of Congress.
displayed
Photo: NOAA
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800 AD – 1600 AD
LONGER VOYAGES & NEW DISCOVERIES
800AD
900
1400
1500
Viking Voyages
Vasco da Gama
Around the World
1600 AD
Photo: LoC
1519
The Vikings explore and colonize
Ferdinand Magellan leads the first
Iceland, Greenland
and
The Portuguesefleet
explorer
Vasco da
Gamathe world.
in a voyage
around
Newfoundland. Theysails
arearound
also among
the
southern
of Africa
Although
histip
fleet
completes the
the first to use becoming
the North Star
to
the first
European
to reach
journey,
Magellan
diesIndia
before its
determine their latitude. end
by on
sea.
an island in the Phillippines.
The photo shows one of the crew’s
landing sites in Guam.
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Photo: NOAA
1600 AD – 1800 AD
NEW NAVIGATIONAL TECHNOLOGY
1600AD
First Submarine
1700
Voyage of Endeavor
1800 AD
The Nautilus
James Cook explores and maps the
Pacific Ocean throughout the 1760s
1770s. develops a
Robert and
Fulton
He is one
of the
first people
to
submarine
that
uses
a
Cornelis Drebbel, horizontal
a Dutchaccurately
longitude
rudderdetermine
to control
physician, builds the world’s
firstmovement.
his position at sea
verticaland
Thisusing
submarine. It can divesystem
to a depth
a forms
new invention
called
the basis
forthe
of 12-15 ft.modernchronometer.
submarines.
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1800 AD – 1900 AD
SURVEYING MARINE LIFE
1800AD
1825
SCUBA
1872-1876
The Challenger
1882
The Albatross
The Challenger
The U.S. Fisheries circumnavigates
Commission
the
launches the first oceanographic
globe in the first great
vessel built solely for research
of
oceanographic
marine life. This steamer
was aModern
expedition.
William H. James of England designs a
major source of marine
research is based
oceanography
Self-Contained Underwater Breathing
for 40 years.
on the physical and
Apparatus (SCUBA) that allows the
biological research
wearer to breathe underwater for up to
The photo shows The Albatross
conductedinon this
an hour.
the early 1900s. Photo: NOAA expedition.
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1900AD
1900 AD – PRESENT
EXPLORATION CONTINUES
1900AD
1943
Photo: NOAA
Modern SCUBA
1960
Trieste Exploration
1985
present
Titanic Discovered
A team of scientists
discoversJacques
the remains
of and Don
Piccard
the Titanic, which
in the
Walsh sank
explore
1912.
Marianas
Trench aboard
Jacques Cousteau and Emile Gagnan
the submersible Trieste
develop modern SCUBA gear that allows
(pictured left in 1960) To
explorers to stay underwater for
date, they are 2 of the 3
extended time.
people to have traveled to
the bottom of the Trench.
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DID YOU KNOW…
…most of the Earth’s ocean is unexplored?

Less than 5% of the ocean has been discovered

Today scientists rely on modern technology like
satellites, buoys and submersibles to explore

They also use computers and mathematical models
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STUDENT ACTIVITY
In today’s activity we will learn how oceanographers
navigate the oceans
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Lesson 3:
Ocean Acidification
Chemical Oceanography
CARBON IS AN IMPORTANT PART OF OCEAN
CHEMISTRY
1.
The ocean absorbs carbon dioxide from the atmosphere
2.
Human activities release carbon dioxide into the
atmosphere
3.
Too much carbon dioxide in the ocean has the potential
to harm marine organisms and ecosystems
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THE OCEAN IS A CARBON SINK
 The ocean absorbs CO2 from the atmosphere
 Physical and biological processes move some of the carbon
to the deep ocean where it is stored
 Carbon sink: a natural or manmade reservoir that
accumulates and stores some carbon-containing chemical
compound for an indefinite period.
 The capture and storage of carbon is known as carbon
sequestration
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HOW MUCH CO2 CAN THE OCEAN ABSORB?
 The total amount of any gas seawater can absorb depends
on temperature and salinity
 Salinity is a measure
of the dissolved salt
content of water
Remember this relationship!
Temperature
or
Salinity
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Amount of gas
seawater can absorb
CARBON DIOXIDE IN THE OCEAN
•When dissolved in water, carbon dioxide forms
carbonic acid that primarily dissociates into
bicarbonate and hydrogen ions
•Some of the excess hydrogen ions combine
with carbonate, decreasing carbonate
availability to marine organisms.
•Carbonate is used by marine organisms
like this pteropod (marine snail) to create
the compound calcium carbonate
Calcium carbonate is the material that composes the shells and
exoskeletons of many marine organisms
CARBON DIOXIDE IN THE OCEAN
Combines with
carbonate ions to
form bicarbonate
ions- taking
carbonate ions
away from marine
organisms!
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Used by marine
organisms to
make calcium
carbonate,
CaCO3
REMEMBER YOUR PH SCALE
 pH= -log[H+], so the lower the pH, the more H+
 Remember your pH scale from chemistry:
acidic
(high H+ )
neutral
basic
(low H+ )
7
14
0
Vinegar
~3
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Ocean water
~8
Ammonia
~11
HUMANS AFFECT THE AMOUNT OF CO2 IN THE
OCEAN
Transportation, industry and things we do at home, like use
electricity, have contributed to rising CO2 emissions to the
atmosphere, which are then absorbed by the ocean
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OCEAN PH LEVELS ARE DECREASING
• Data from scientists show that average ocean pH has
decreased between the 1700s (pre-industry) and the
2000s
• Observations at monitoring stations across the ocean
have shown this decreasing trend
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STUDENT ACTIVITY
 What impacts might increased ocean acidity have on
marine life?
 We will explore some of these impacts in our activity
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WRAP-UP: HOW IS MARINE LIFE AFFECTED?
 As you saw in the exercise, CaCO3 is broken down in acidic
solution
 Shells of marine life can begin to dissolve in high CO2
concentrations.
 Ocean Acidification by the Alliance for Climate Education
Video
HOW IS MARINE LIFE AFFECTED?
Sensitive
ecosystems like
coral reefs may
decline due to
change in pH
and slower
construction of
coral
exoskeletons.
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Photo: NOAA
HOW IS MARINE LIFE AFFECTED?
Reduced abundance of small shelled organisms may cause
problems for those larger species that prey upon them for food
Photo: NOAA
Interference with
marine
mammal
communication
27 is possible!
Lesson 4:
The Biogeochemical Cycle
Chemical Oceanography
LAST CLASS WE LEARNED ABOUT CO2 IN THE
OCEANS
 What is the average pH in the ocean?
 How can increases in CO2 affect:
 Ocean pH?
 Calcium carbonate?
 What substance do marine organisms use to make
exoskeletons?
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TODAY WE WILL LEARN MORE ABOUT ORGANIC
OCEAN CHEMISTRY
1.
The biogeochemical cycle is the continuous flow of
elements and compounds between organisms and
the earth
2.
The ocean plays a role in the biogeochemical cycle for
elements including carbon and nitrogen
3.
As part of the carbon cycle, carbon dissolves into the
surface ocean from the atmosphere and is used for
photosynthesis
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THE BIOGEOCHEMICAL CYCLE
Atmosphere
Biosphere
Hydrosphere
Lithosphere
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The biogeochemical cycle
involves the movement of
elements and compounds
among the land
(lithosphere), organisms,
air (atmosphere) and the
oceans (hydrosphere).
Human activities can
affect these cycles
HOW DO ELEMENTS MOVE THROUGH THE
BIOGEOCHEMICAL CYCLE?
Elements travel
among air, land and sea
through
physical processes
Organisms use
elements as
nutrients
and put
nutrients back
into the
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environment
WHAT ELEMENTS ARE IMPORTANT TO MARINE
LIFE?






Carbon (C)
Nitrogen (N)
Phosphorus (P)
Silicon (Si)
Iron (Fe)
Trace metals
A trace element exists at LESS
THAN 100ppm
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CARBON CYCLING IN THE OCEAN: THE
“BIOLOGICAL PUMP”
 Today we will focus on carbon cycling.
 We’ll examine the processes that transfer carbon from the
ocean surface to the deep ocean and throughout the food
chain.
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Phytoplankton
CO2
use
CO2 for
photosynthesis
Some
CO2 is given back off
through respiration
Carbon moves up the
COchain
food
as primary
2
consumers like
Respiration
zooplankton eat
phytoplankton
As phytoplankton
die and
decompose,
carbon settles to
the
deep ocean
Carbon
Decomposition
moves
further up to
secondary and
tertiary consumers
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STUDENT ACTIVITY
 In groups of 2-3 (NO LARGER!) please complete the
packet with 30 questions.
 Hand in 1 per group in the tin at the front of the room
BEFORE you leave today for full credit.
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Lesson 5:
The Dead Zone
Chemical Oceanography
LAST CLASS WE LEARNED ABOUT THE CARBON
CYCLE
 What is a biogeochemical cycle?
 What are the primary components of the carbon cycle?
 Besides carbon, what other cycling elements are
important to ocean life?
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TODAY WE WILL LEARN ABOUT ANOTHER ELEMENT
THAT CYCLES THROUGH EARTH’S SYSTEMS
1.
Nitrogen is an important element to marine life.
2.
An excess of nitrogen can indirectly lead to a
reduction of dissolved oxygen in the water.
3.
Low oxygen conditions can result in large marine
die-offs.
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WELCOME TO THE DEAD ZONE!
Dead zone
Dead zone
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The Dead Zone is
a region in the
Gulf of Mexico
that does not
support marine
life in surface
waters
Approximate
location shown
here
WELCOME TO THE DEAD ZONE!
 This region cannot support life because there is little
to no dissolved oxygen (DO) in the water
 Similar zones occur throughout the world
 What do you think might cause them?
 Too many nutrients like nitrogen can cause them
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HOW DOES NITROGEN GET IN THE
OCEAN?
Atmosphere
Nitrogen is part of the
biogeochemical cycle.
Factories
Human activities like those in
the picture cause nitrogen to
enter the water. For example:
agriculture, industry
and water treatment.
Fertilizers
Wastewater
treatment
Let’s see why too much
nitrogen reduces DO…
Photo: USGS
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TOO MUCH NITROGEN CAUSES PLANKTON
BLOOMS
 Nitrogen is important to marine life
 Plankton, marine organisms that drift through the ocean (fish larvae,
diatoms), use this nutrient for reproduction
 Excess nitrogen from human activities allows plankton populations to
grow very rapidly, a phenomenon called a plankton bloom
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Plankton
HOW DO PLANKTON BLOOMS LEAD TO DEAD
ZONES?
Those organisms that
cannot or do not leave
will die off
In hypoxic (low DO) or
anoxic (no DO)
environments, fish and
When plankton die, they
other mobile organisms
settle to the bottom and
will leave
decompose
Bacteria use up oxygen
as they decompose the
plankton
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Plankton
DO
DEAD ZONE ACTIVITY
 Rainbow Salt Lab
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Lesson 6:
Ocean Layers I
Chemical Oceanography
WE HAVE BEEN LEARNING ABOUT OCEAN
CHEMISTRY
What are two important cycling nutrients we have
learned about?
N&C
Name one way human activities affect each of
these nutrients.
What is a Dead Zone?
Is the Dead Sea really dead?
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SALINITY IS ANOTHER IMPORTANT PART OF
OCEAN CHEMISTRY
1.
Salinity is a measure of the amount of dissolved salts
in water
2.
Salinity is not homogenous (uniform) across the
Earth’s oceans
3.
Both salinity and temperature affect the density of
seawater
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SEAWATER IS A MIXTURE OF PURE WATER AND
CHEMICAL COMPOUNDS
On average,

Seawater is 96.5% pure
water…

…and 3.5% compounds
including dissolved salts

Remember from chemistry
that when salts dissolve
they form ions
Na+
Sodium
Chloride
(A salt)
Cl-
Water
Na+
Sodium ion
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Cl-
Chloride ion
SALINITY IS A MEASUREMENT OF HOW MUCH
SALT IS DISSOLVED IN THE WATER
 Common units of salinity are:
 Parts per thousand (PPT)
 Practical Salinity Units (PSU)
 What does ppt really mean?
 Imagine you have a bag of 1000 m&ms
 Blue m&ms represent pure water
 Red m&ms represent salts
 To represent 35ppt (average salinity of seawater), 35 m&ms would
be red and 965 would be blue.
WHAT’S IN THE WATER?
 7 primary chemicals make up almost all (~99%) the salts in
seawater:







Chloride (Cl-): 55%
Sodium (Na+): 31%
Sulfate (SO42-): 8%
Magnesium (Mg2+): 4%
Calcium (Ca2+): 1%
Potassium (K+): 1%
Bicarbonate (HCO3-): < 1%
 Can you come up with an acronym to remember them all?
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HOW DO SCIENTISTS FIGURE OUT HOW MUCH
SALT IS IN THE WATER?
 The Rule of Constant Proportions = elements in a
compound are present in a fixed proportion
 This means that although salinity may vary, the ratio of any
one of the 7 primary ocean salts to each other will not
change
 Therefore if scientists figure out the amount of one primary
ocean salt, they can then calculate the amount of the other
six, and thereby determine the sample's salinity
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HOW DO SCIENTISTS FIGURE OUT HOW MUCH
SALT IS IN THE WATER?
 Scientists have several tools to measure the amount of ions
 The newest method is a NASA satellite that will actually
measure salinity from space
The Aquarius: NASA
53 satellite
that measures ocean salinity
THE TITANIC
TITANIC FACTS
 1912 Titanic struck an iceberg in the North Atlantic ocean
southeast of Newfoundland Canada
 Voyage from Southampton England to New York
 Ships bow moved below the frigid surface assuming vertical
position
 Among the worst human disasters that occurred at sea
2224 passengers -1513 drowned, 711 survived
WHY CONSIDERED“UNSINKABLE”
 16 watertight compartments to keep the ship afloat
 So convinced wouldn’t sink, only provided 20 lifeboats
 Why were the builders wrong?
 Why do some objects sink and others float?
http://channel.nationalgeographic.com/channel/a-night-of-exploration/videos/titanic-sinkingcgi/
BUOYANCY
The Greek scientists Archimedes discovered that floating objects are
supported by buoyancy
 Archimedes principles:
 The buoyant force on any object is equal to the weight of the liquid that the
object displaces
 A body immersed in a liquid seems to lose weight, and the weight lost is equal
to that of the liquid displaced
Buoyant force = weight of liquid displaced = loss of weight in liquid
Why do we need to know about buoyancy?
BUOYANCY HELPS EXPLAIN WHY SHIPS
SINK!
WHY SHIPS FLOAT
 Constructed with many airfilled compartments
 Air weighs less than water
 Weight of air and steel is less
than the water displaced by
the ship
 Anchor sinks because it
weighs more than the water
displaced
WHY SHIPS SINK (Titanic)
 Huge gash caused the
watertight compartments to
fill up with water
 In time, the combined weight
of the water and weight of the
ship became greater than the
buoyant force supporting the
ship; causing the ship to sink
Titanic sank in 1912, not found
until 1985
Robert Ballard: deep sea explorer who first discovered the
location of the Titanic
FACTORS THAT INFLUENCE SALINITY
 Three primary factors influence
salinity:
 1. Freshwater input - High rates of
freshwater input (river inflow to
the sea; melting ice) will decrease
salinity
 2. Evaporation - High rates of
evaporation will increase salinity
 3. Precipitation - High levels of
rainfall will decrease salinity
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SALINITY IS VARIABLE ACROSS THE OCEAN
Salinity is highest
in the mid -latitudes and
lowest at the equator
and high-latitudes
Photo: NASA
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A CLOSER LOOK
Relatively
LOW
salinity
Relatively
HIGH
salinity
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WHY IS SALINITY IMPORTANT?
 Salinity is one factor that controls the density of ocean water
 What happens when water at different depths has different
densities?
 Layers of water will form
 Formation of layers is part of the reason we have ocean currents
 We will learn more about ocean currents in another lesson
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STUDENT ACTIVITY
 Today you will answer questions about the dead zone and
salinity.
 This video will help you with your Tinfoil Boat Experiment
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