Transcript OUR LIVING, MOVING SEA

SEA WATER COMPOSITION
I. Salinity: The amount of solid material dissolved in water
A.
1. Seawater is composed of Cl, Na, Ca, Mg, S, K.
These elements make up 99% of the dissolved materials in
the ocean.
B. Sources:
1. Add-weathering of rock, volcanoes, melting
ice, and runoff
2. Remove- evaporation and formation of ice
Why is the ocean salty?
Clip on: why tell me why?
http://videos.howstuffworks.com/discovery/31006-why-tell-me-whyexplaining-saltwater-video.htm
Areas of Diverse Salinity
C. Variations:
1. Open ocean is between 33-38parts per
thousand
2. Brackish water has been diluted with
fresh water (estuaries and bays)
3. Hyper saline water is typical of inland
bodies of water where evaporation is high
and circulation low.
(Great Salt Lake 28.0%, Dead Sea 33.0%)
Salty lakes hid deep in the
Mediterranean
Geoscientists have discovered three lakes of extremely salty brine
lying in pockets on the floor of the Mediterranean Sea, south
west of the island of Crete. Such Lakes could help explain why
the Mediterranean is saltier than typical ocean water. The three
brine lakes situated more than 3300 meters below the sea surface
were discovered in 1993 and 1994 by a team of European
scientists conducting the Mediterranean Ridge Fluid Flow
project. MEDRIFF Researchers found the lakes using echo sonar
which sends down pulses of sound to probe the seafloor. The
boundary between the dense brine fluids and normal seawater
above creates a flat lake surface that stands out amid rougher
surrounding seafloor. The density contrast prevents the brine
from mixing easily with the seawater.
Salty lakes hid deep in the
Mediterranean
The scientists focused attention on a horseshoe-shpaed
lake, called Urania which had an average depth of 80
meters. The chloride content in the Urania brine
measured about 5X’s that of Mediterranean seawater.
The lakes formed when seawater dissolved deposits of
salt-rich rocks along the seafloor. These lakes may
explain the Mediterranean’s high salinity. Current
theories explain the high salinity to high evaporation
rates.
How does salinity affect the
density of water
Complete the Inquiry Activity from pg. 421
Answer the Analyze and Conclude questions in your
notebook
Homework: pg 427
#1-5 and writing in science
Effects of Salinity
D. Effects of Salinity
1. Salinity increases density
But is not a significant factor
in determining density at
depth (temperature is more
important)
2. Average ocean water has a salinity of
35g/1000ml.
The Range is 33-37 ppt
3. Salinity increases
temperature
at which water boils
4. Temperature is inversely proportional to density
Decrease in temp=increase in density
Increase in temp=decrease in density
5. Buoyancy changes with
changes in salinity
(higher=more buoyant,
lower=less buoyant)
due to density
Salinity and Humans
Lack of salt in a diet can produce goiters and
associated health issues
Salinity Notes
 Freshwater coming in from rivers and precipitation
make lower salinity
 Salinity is higher in polar regions because salt is left
behind when water freezes
 Density of salt water is greater than fresh water. Fresh
water floats on salt water
Temperature
•Temperature differences are caused
by solar radiation at different latitudes
•As you get closer to the poles the
angle of radiation from the sun
decreases and radiation is spread
over a larger surface area
•Deep ocean water is the same
temperature as the polar region
surface waters
•There are rapid temperature changes
in the first kilometer of depth
Density
 Dependent on salinity and temperature
 Salinity increases, density increases
 Temperature increases, density decrease
 Less dense water remains at the surface
 In the open ocean, temperature is more important in
determining density—Near shore the salinity is more
important in density determination
Thermocline-Rapid change in decreased temperature
Pycnocline-rapid change in density
Halocline-rapid change in salinity
Water Molecule
 Atoms are made up of:
 Protons, Neutrons, Electrons
 Molecule: a combination of atoms which are bound
together. Three important bond types:
 Ionic bonds: complete transfer of electrons (for example
salts like NaCl)
 Covalent bonds: sharing of electrons (for example water
H2O)
 Metallic bonds (for example Fe)
Water Molecule: Covalent Bonds
In water, each hydrogen nucleus is bound to
the central oxygen atom by a pair of
electrons that are shared between them;
chemists call this shared electron pair a
covalent chemical bond.
Water Molecule: The Sharing is
Not Equal!
Each electron from hydrogen atoms is
pulled slightly toward the positively
charged protons in the nucleus of the
oxygen atom, creating a slight positive
charge on the exposed “hydrogen end” of
the water molecule, and a slight negative
charge on the “oxygen end” of the water
molecule
Water Molecule: Water is special
This property makes each water molecule
like a tiny, weak magnet. Magnets have
positive and negative “poles,” so water
molecules are called “polar.”
Water Molecule: Water is special
 The fact that water molecules are polar gives rise to
some interesting properties:
 The attractive forces between water molecules allows
water to be a liquid rather than a gas at room
temperature
 Water makes a great “solvent.”:
Solvent: a solid, liquid or gas that dissolves another solid, liquid
or gas, creating a solution.
When materials, especially salts, are added to water the
molecules are surrounded by water molecules and then easily
dissolved
 Surface tension
Making a water molecule
 Follow the instruction on the water molecule
worksheet
 Please return the information sheet to me.
Homework 15.1
Answer questions 6-8 on pg 427
Next time:
Salinity of Sound water and making a hydrometer lab
Agenda
1.
2.
3.
4.
5.
6.
Quiz
Complete Hydrometer Lab—turn in
Check on salinity of sound lab-complete if evaporated, make
sure to compare the information from the salinity lab to the
hydrometer reading for colvos passage and Sinclair Inlet
Notes on Water special Properties
Salinity Worksheet
Composition of water
Complete worksheets for homework
Water Video clip
http://videos.howstuffworks.com/hsw/16875-the-watercycle-fresh-water-vs-salt-water-video.htm
http://videos.howstuffworks.com/hsw/9926-thebiology-of-water-the-hydrologic-cycle-video.htm
Water’s Special Abilities
II. Water’s Special Properties
A. Heat Transfer
1. Conduction: Transmission of heat from a region
of higher temperature to a region of lower
temperature.
2. Heat is conducted away from a body 10X faster
in water than in air.
B. Water & Light
1. Light Penetration: Only about 20% of sunlight
reaches 30 feet in clear water.
a. Photosynthesis occurs at depths up
to 300 feet in clear water.
b. Turbidity: suspended particles affect
light penetration.
c. Color dissipates at different depths due
to the different wavelengths. Color is lost
in the order of Red, Orange, Yellow,
Violet, Green, and Blue.
(florescent colors emit color when
stimulated any light of shorter wavelength)
d. Magnification-objects appear 25% larger
underwater and often closer due to refraction
e. Sound-water is a good conductor of sound due
to the density. Sound in seawater travels 4X
faster, allowing sound to reach the ears at the
same time.
Agenda
Quiz
2. Notes on ocean zones and organisms
3. Worksheet: Physical properties of Ocean zones
1.
Homework:
Section 15.2 #1-5
Layers of the Ocean
III. Three Major Zones: Shallow Mixed (Surface),
Transition Zone, Deep Zone
A. Shallow Mixed: Surface H2O has a uniform
temp and usually extends to 300m.
B. Transition Zone: Temperature falls abruptly
creating a thermocline, accounts for 18% of all
the sea
C. Deep Zone: Temperature is a few degrees
above freezing and initiates deep ocean
currents.
Marine Organisms--15.2
IV. Types of Organisms:
A. Plankton: These organisms are drifters and
include phytoplankton and zooplankton.
1. Phytoplankton: Consist mostly of
unicellular algae that are photosynthetic.
a. Also includes Diatoms (main
primary producers) and
Dinoflagellates (cause red tide and
bioluminescence)
2. Zooplankton: Consist of herbivores
grazing on phytoplankton or carnivores
eating other zooplankton.
B. Nekton: Includes all animals that are capable
of moving independently.
1. Includes all fish, marine mammals &
reptiles, squid and shrimp are only inverts.
C. Benthos: Organisms that inhabit the bottom of
the ocean.
1. Includes all organisms that live on the
bottom both in shallow and deep water.
Life Zone Areas
V. Three Factors that Affect Distribution of Life: Light
Penetration, Distance from Shore and Depth
A. Light Penetration: Photic Zone is affected by
sediments, plankton, and decaying organic
particles. Divided into 2 individual sub-zones
1. Euphotic: Where photosynthesis occurs up
to a max depth of 300ft
2. Aphotic: There is not enough light for
photosynthesis, but marine animals use this area
to avoid predators.
Agenda
Quiz
Look at Grades
Finish notes
Study Guide
Test next time
Water population videos
http://videos.howstuffworks.com/hsw/9927-thebiology-of-water-population-and-demand-video.htm
http://videos.howstuffworks.com/hsw/9920-thebiology-of-water-tillamook-bay-video.htm
B. Distance from Shore: Subdivided into 3 areas
1. Intertidal-zone affected by tidal change
2. Neritic-part of the continental shelf,
accounts for 90% of the World’s fisheries
3. Oceanic- open ocean with fewer organism
C. H2O Depth: Divided into Three major areas
1. Pelagic-open ocean
2. Benthic-bottom areas, both shallow and deep
3. Abyssal-deep ocean with high pressure, cold
temperature and little food
D. Hydrothermal Vents: Areas of extreme high
temperatures, volatile gases, dissolved nutrients,
large amounts of mineral precipitants.
Primary Production
VI. Primary Productivity: Production of organic
compounds from inorganic compounds via
photosynthesis or chemosynthesis
A. Polar Regions: Solar radiation limits
nutrients
B. Temperate Regions: Limited by sunlight
and nutrient supply cycles
C. Tropical Oceans ( a biological desert): is
limited because of lack of nutrients
because surface waters don’t mix with
the nutrient rich deeper waters
Feeding Relationships
Trophic Levels: Energy transfer within the
food chain.
1. Transfer of energy between levels is very inefficient only
about 2%
2. Trophic levels are the feeding stages (algae, zooplankton
and herbivores, carnivores, larger carnivores
3. Food chain is a sequence of organisms through which
organisms are transferred.
4. Food web is a complex series of feeding relationships
with many organisms relying on multiple sources of food.