Name:__________________________
Per__________
Marine Chemistry
1. Water on earth
a. Earth is the only place in universe that has water in all 3 states (Solid, liquid, and gas)
i. Most water is in Liquid form
ii. The vast majority of water on earth is salty
2. Why is water unique
a. Water can form hydrogen bonds
i. A water molecule contains 2 elements, hydrogen and oxygen
ii. When hydrogen and oxygen bond electrons spend more time around the oxygen atom than the
hydrogen atoms
iii. This uneven sharing of electrons results in a negative charge on the oxygen end of a water
molecule and a positive charge on the hydrogen end of the water molecule
1. Hydrogen Bond – a weak attraction between the oxygen end (-) of one water molecule
and the hydrogen end (+) of a second water molecule
Name:__________________________
Per__________
3. Why are Hydrogen bonds important
a. Hydrogen bonding causes water to heat up and cool down slower
i. The hotter any material gets the faster the molecules of a substance move
ii. Waters hydrogen bonds limit the amount of movement water molecules can have. This means
that water heats up much slower than other substances
iii. Heat capacity – The
amount of heat energy
needed to raise the
temperature of a
substance
4000
1. Because of
3500
hydrogen bonding
3000
2500
water has a high
2000
heat capacity. This
1500
means it heats up
1000
and cools down
500
0
much slower than
other substances.
2. Waters high heat
capacity allows
most marine organisms to be cold blooded because water isn’t subject to rapid
temperature changes
3. Also the stable temperature of ocean water helps regulate temperature changes on
earth by cooling hot air and heat up cold air
Heat Capacity of Common Substances
http://www.youtube.com/watch?v=4RyQM-7Ftvs&feature=related
Heat Capasity (J/goC)
Heat Capacity of Common
Substances
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Per__________
b. Hydrogen bonding causes water to have a high viscosity
i. Waters ability to hydrogen bond stops water molecules from sliding (flowing) past each other
easily
ii. Viscosity – a liquids tendency to resist flowing
1. “Thick” liquids like syrup and molasses have a high viscosity
2. “Thin” liquids like alcohol are considered to have a low viscosity
3. Water is considered to be a relatively viscous substance, therefore most small marine
organisms float or drift (plankton) instead of swim
Viscosity of Common Liquids
6
Viscosity
5
4
3
2
1
0
http://www.youtube.com/watch?v=iagQtBWwZu8
c. Hydrogen bonding causes Ice to float on liquid water (if not then oceans would freeze)
i. When liquid water cools the molicules move slower and pack closer together (take up less
volume)
ii. Because the volume of liquid water decreases without changing the mass water gets denser as
it cools
iii. When water freezes and becomes ice, the water molecules move so slowly that every water
molecule begins to form hydrogen bonds
iv. The increase in hydrogen bonding causes the water molecules in ice to spread out and occupy
more space
v. Because the volume of ice increase without changing the mass water gets less dense when
it freezes and so ice will float on liquid water
1. A floating layer of ice leaves water below for organisms to live, if ice where denser than
liquid water the oceans would freeze from the bottom and no life would exist in
the oceans
Name:__________________________
Per__________
Pipe
http://www.youtube.com/watch?v=PcoiLAsUvqc&feature=related
4. What is in Salt Water (Salt)
a. Salt is more than just NaCl or table salt.
b. Salt - Any molecule made out of oppositely charged particles is a salt
c. When any salt is put in water, the charged water molecules surround the salt particles and cause them
separate and dissolve
d. The charged particles in salt water mostly come from weathering rock and volcanic activity
Name:__________________________
Per__________
e. Because oceans are the last pooling place of water, ocean water has typically weathered the most rock
and dissolved the most volcanic gasses and thus is more salty than the fresh water that is found on land
Salinity – the total amount of salt (charged particles) dissolved in water
i. The average salinity of ocean water is 35ppt (1000 part per thousand by mass). This mean that
in 1000 Lbs of salt water there are 35Lbs of dissolved salt, or in 100 Lbs of salt water there are
3.5lb’s of salt
ii. Though ocean water is usually around 35ppt, salinity of ocean water can change with depth,
temperature and location
g. Rule of Constant Proportions – The percentage of charged particles that make up the salt in salt water
always remain the same
i. Though the salinity of ocean water can change the recipe of how you make the salt will
always remain the same
f.
5. What is in salt water (Gas)
a. Three main gasses in the atmosphere are the same as in the ocean (O2, CO2, and N2). Is because
most of the gas dissolved in ocean water comes from air
b. However the amount of each of those gasses is not the same as it is in air
Name:__________________________
Per__________
Comparitive % Of Gases
% in atmosphere
% in surface water
% in total ocean
83
78.08
48
36
21
15
11
N2
6
O2
0.03
CO2
0.89 1
0
Trace Gasses
6. O2
a. Salt water has a much lower concentration of oxygen than in air
b. The concentration of oxygen in sea water is higher on the surface than in deeper water because
oxygen gets into water through both air and photosynthesis
c. Oxygen minimum zone – aria of water just below sunlit surface water where oxygen concentration
drops suddenly because it is being removed by organisms but not added by photosynthesis
i. Below the oxygen minimum zone the concentration of oxygen increases due to less organisms
as well as downwelling
Data used is from the tropical Pacific Ocean (solid line) and the tropical Atlantic Ocean (dashed line)
Name:__________________________
Per__________
7. CO2
a. Carbon dioxide 50x more concentrated in water than in air because it chemically reacts with
water as it dissolves to form carbonic acid
b. The chemical reaction between carbon dioxide and water forms bicarbonate witch buffers sea water
and causes sea waters PH to stabilized at a pH of 8
c. Oceans are a CO2 storage, they absorb 1/3 of the CO2 in the atmosphere
8. The Importance of CO2 in the ocean
a. The pH (how acidic/basic) of the ocean is regulated by Carbon dioxide
i. Because of this buffering system the oceans acidity remains relatively stable at a pH of 8 (slightly
basic)
ii. Ocean acidification
1. Since 1850 the amount of CO2 in the atmosphere has risen which caused more CO2 to
become dissolved in water
2. This High concentration of CO2 in ocean water has produced large amounts of carbonic
acid (the acid that makes soda sour and necessitates so much sugar to balance it out)
3. As a result of this excess carbonic acid Ocean water has become 30% more acidic than it
was 150 years ago
4. The higher level of acidity caused great changes in the ocean:
a. Erodes shells of oysters, clams
b. Weakens exoskeletons of crustaceans like krill , crabs, and shrimp
c. Effected corals ability to form limestone skeletons so coral reefs have begin to
collapse
d. Squids and other nekton cant exchange CO2 as easily with the water and so
they suffocate at greater rates
e. As a result larger fish, whales, birds, and humans have experienced a drop in
their food supply
pH of 8

pH of 5
b. N2
i. enters water mostly from atmosphere
1. The nitrogen cycle is becoming disrupted
a. Since the industrial revolution increased populations of people have required
more food
b. As a result industrial farming methods have been adopted that require the use
of nitrogen fertilizers to support the food demands of the world
Name:__________________________
Per__________
c. This nitrogen fertilizer runs into the ocean which boosts the amount of nitrogen
in the ocean and to a level where natural denitrofication can’t handle it and
leads to eutrophication
d. Eutrophication – excessive algal growth due to excess amounts of nitrates
in water
i. Eutrophication leads to blooms of harmful algae which causes fish
populations to spike beyond what the ecosystem can handle
ii. After the initial spike all the oxygen and nutrients are used up and
organism populations decline greatly in that area
c. Effects of temperature and salinity on Ocean water
i. Salt water is more dense than fresh water
ii. Density is dependent on both temp and salinity but more so temp because it varies more
though out the ocean
1. Cold salty water is more dense and tends to sinks
2. Hot fresh water is less dense and tends to float
iii. As you move deeper and deeper in the ocean you lose the warming effects of the sun and air,
and thus the temperature of the water cools and the density of the water changes
1. Thermocline – layer of water that shows a large amount temperature changes
with depth
iv. This gradual cooling of ocean water with depth has produced and ocean with Three distinct
layers of temperature, salinity and density
1. Surface layer (0  ≈600 ft)
a. At the surface the density of water can vary greatly due to the effects of the
seasons and location on temperature and salinity,
b. Overall surface water overall tends to be less dense than the water below
due to the warming effects of the sun and air
Name:__________________________
Per__________
2. Intermediate layer (600 ≈5000ft)
a. The intermediate layer of the ocean has the main thermo cline
i. Main or permanent ocean thermocline - transition zone between
warm surface waters and cold deep waters.
ii. Main thermocline is deep enough that it is not effected by the
seasons or geographic location
iii. At the intermediate layer relatively warm less dense surface water
transforms into colder dancer deep ocean water
3. deep layer (5000 ≈bottom)
a. The bottom layer is uniformly cold and uniformly salty and therefore has a
uniform and relatively high density
1) Light and water
a) Like many objects water tends to reflect or absorb different colors of visible light.
i) Our eyes only see the colors of light that are reflected not absorbed
(1) White light is the color seen when an object reflects all colors of visible light
(2) Black is seen when visible light is absorbed by an object
ii) Therefore when white light (containing all colors if light) hits a red shirt, all the colors of light in the white
light are absorbed except the color red which is reflected
An Orange Shirt
A White Board:
Light colors reflected:
Orange
Light colors reflected:
all
Light colors absorbed:
All but orange
Light colors absorbed:
None
Name:__________________________
Per__________
A Black Pair of Jeans
A red shirt in a room with only blue light
Light colors reflected:
none
Light colors reflected:
none
Light colors absorbed:
all
Light colors absorbed:
Blue
What color does the shirt appear?
Black
b) When white light hits water, not all colors are
absorbed at the same rate
i) red light is absorbed first, and blue
and green light are absorbed last.
ii) This means that blue light in the ocean
penetrates water the deepest and red light the
least.
iii) Eventually as you get deeper and deeper
in water more and more light is absorbed or reflected
until all the colors of light are gone and the water
appears black
(1) This means that organisms that are
red at the surface look grey or black at depth because
all the red light has been absorbed and thus there is
no light to reflect.
(2) This is why most small fish and
invertebrates in the ocean are red
Name:__________________________
Per__________
Though all colors of light are present at the surface to create white and blue colorations, at the depths
all colors of light are absorbed except for blue and green. This causes all colors that aren’t white, blue or
green to appear as black.
2) Sound and water
a) Because liquid water molecules are closer together than air molecules a sound wave can travel better through
water than air
b) Slower moving low frequency sound has the ability to go farther in water because it can pass through
objects like dirt and fish more effectively
c) Two factors that effect the speed of sound in water are temperature and pressure
i) Temperatures effects on the speed of sound:
(1) colder water slows sound down more than warmer water
(2) Therefore, just taking temperature into consideration the farthest traveling sound would happen on the
bottom of the ocean
ii) Pressures effects on the speed of sound
(1) Low pressures slows sound down more than high pressure water
(2) Therefore, just taking pressure into consideration the farthest traveling sound would happen on the
surface of the ocean
Name:__________________________
Per__________
d) Because temperature allows sound to travel the farthest in deep water and pressure allows sound to travel the
farthest in shallow water, when the effects of both temperature and pressure are combined, the effects of both
overage out to give a zone in the middle of the ocean where the speed of sound is the slowest and therefore
sound travels the farthest
(a) The SOFAR channel – a layer of water where sound has the ability to travel great distances due to
the slowing effects of temperature and pressure at this depth
(i) Whales like the humpback whale “sing” at this depth to insure that a maximum of females can
hear their song