Exit
Choose to view chapter section with a click on the section heading.
►The Water Planet
►Water’s Unique Properties
►The Inorganic Chemistry of Water
►The Organic Chemistry of Water
►Chemical Factors That Affect Marine Life
Ch
ap
ter
To
pic
Me
nu
Menu Previous Next
8 - 2
The Water Planet
Th
e W
ate
r P
lan
et
Cha
pter
8 P
ages
8-2
to
8-5
Menu Previous Next
8 - 3
The Water Planet
Water covers about 71% of the Earth’s surface. Considering the depth and volume, the world’s ocean provides more than 99% of the biosphere – the habitable space on Earth.
The vast majority of water onEarth can’t be used directly fordrinking, irrigation, or industrybecause it’s salt water.
Th
e W
ate
r P
lan
et
Cha
pter
8 P
ages
8-2
to
8-5
Menu Previous Next
8 - 4
The Water Planet
As the population increases, so does the need for water.Part of the solution to meeting this demand lies in
understanding what water is, where it goes,and how it cycles through nature.
Th
e W
ate
r P
lan
et
Cha
pter
8 P
ages
8-2
to
8-5
Menu Previous Next
8 - 5
The Water Planet
The Hydrologic Cycle.
Th
e W
ate
r P
lan
et
Cha
pter
8 P
ages
8-2
to
8-5
Menu Previous Next
8 - 6
The Water Planet
The ocean is vast.Considering depth and volume, the world’s ocean
provides more than 99% of the biosphere - the habitable space on Earth.
The entire ocean is a biosphere - organisms live everywherein the water column.
How does this compare toland animals?
Th
e W
ate
r P
lan
et
Cha
pter
8 P
ages
8-2
to
8-5
Menu Previous Next
8 - 7
The Water Planet
Our ocean on planet Earth averages 3,730 meters (12,238 feet) deep and it contains more than 1.18 trillion cubic kilometers (285 million cubic miles) of water.
The deepest known pointin any ocean is theChallenger Deep inthe Mariana Trench.
Th
e W
ate
r P
lan
et
Cha
pter
8 P
ages
8-2
to
8-5
Menu Previous Next
8 - 8
Water’s Unique Properties
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-5 t
o 8-
8
Menu Previous Next
8 - 9
The Polar Molecule
Molecules are the simplest part of a substance. Compared to many important
molecules, water is a simplemolecule - it’s chemicalsymbol = H2O.
Consists of three atoms - twohydrogen and one oxygen.
The way it’s held togethergives it unique properties.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-5 t
o 8-
6
Menu Previous Next
8 - 10
The Polar Molecule Covalent bonding.
Covalent bonds result in theformation of molecules.
The hydrogen atoms bondto the oxygen atoms with acovalent bond.
A covalent bond is formed byatoms sharing electrons. Thismakes water a very stablemolecule. In water, the oxygenatom shares the electrons of two single-electron hydrogen atoms.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-5 t
o 8-
6
Menu Previous Next
8 - 11
The Polar Molecule
A molecule with positive and negative charged ends has polarity and is called a polar molecule.Water is a polar molecule.The two hydrogen atoms
have a net excess positivecharge.
The oxygen atom has anet excess negative charge.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-5 t
o 8-
6
Menu Previous Next
8 - 12
The Polar Molecule
The water molecule’s polarity allows it to bondwith adjacent water molecules.
The positively chargedhydrogen end of one watermolecule attracts thenegatively charged oxygenend of another water molecule.
This bond between watermolecules is called ahydrogen bond.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-5 t
o 8-
6
Menu Previous Next
8 - 13
The Polar Molecule
Hydrogen bonds. Individual hydrogen bonds are
weak compared to covalentbonds - only 6% as strong.
Hydrogen bonds can easilybreak and reform.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-5 t
o 8-
6
Menu Previous Next
8 - 14
The Effects of Hydrogen Bonds
Being a polar molecule, water has these characteristics:Liquid Water. The most important characteristics
of the hydrogen bonds is the ability to make water a liquid at room temperature.Without them, water would be a gas - water
vapor or steam at room temperature.Hydrogen bonds hold the molecules together,
requiring more energy (heat) to form steam.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-6 t
o 8-
8
Menu Previous Next
8 - 15
The Effects of Hydrogen Bonds
Being a polar molecule, water has these characteristics:Cohesion/Adhesion. Because hydrogen bonds
attract water molecules to each other, they tend to stick together. This is cohesion. Water also sticks to other materials due to its polar nature. This is adhesion.
Example of adhesion - a raindrop clinging to the surface of a leaf.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-6 t
o 8-
8
Menu Previous Next
8 - 16
The Effects of Hydrogen Bonds
Being a polar molecule, water has these characteristics:Viscosity. This is the tendency for a fluid (gas or
liquid) to resist flow. Most fluids change viscosity as temperatures
change.The colder water gets, the more viscous it
becomes. It takes more energy for organisms to move through it, and drifting organisms use less energy to keep from sinking.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-6 t
o 8-
8
Menu Previous Next
8 - 17
The Effects of Hydrogen Bonds
Being a polar molecule, water has these characteristics:Surface Tension. A skin-like surface formed due
to the polar nature of water. Surface tension is water’s resistance to objects attempting to penetrate its surface.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-6 t
o 8-
8
Menu Previous Next
8 - 18
The Effects of Hydrogen Bonds
Being a polar molecule, water has these characteristics: Ice Floats: as water cools enough to turn from a
liquid into solid ice, the hydrogen bonds spread the molecules into a crystal structure that takes up more space than liquid water, so it floats.
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-6 t
o 8-
8
Menu Previous Next
8 - 19
The Effects of Hydrogen Bonds
If ice sank, the ocean would be entirely frozen – or at least substantially cooler – because water would not be able to retain as much heat.
The Earth’s climate would be colder – perhaps too cold for life.
So, the question is… “Howimportant is Hydrogen Bondsto your very existence?”
Wa
ter’
s U
niq
ue
Pro
pe
rtie
sC
hapt
er 8
Pag
es 8
-6 t
o 8-
8
Menu Previous Next
8 - 20
The InorganicChemistry of Water
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Cha
pter
8 P
ages
8-9
to
8-23
Menu Previous Next
8 - 21
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Cha
pter
8 P
ages
8-9
to
8-11
Solutions and Mixtures in Water
A solution occurs when the molecules of one substance are evenly dispersed among the molecules of another substance.
Water can act as a solvent. (often called the “universal solvent”)A solvent is the more abundant substance in a
solution; usually a liquid. A solute is the substance being dissolved and is less
abundant in the solution. Solutes are usually a solid or gas.
Menu Previous Next
8 - 22
Solutions and Mixtures in Water
A mixture is the combination of two or more substances that are not chemically bonded, and not in fixed proportions to each other.Two kinds of mixtures: Homogeneous and
Heterogeneous.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-9 t
o 8-
11
Menu Previous Next
8 - 23
Solutions and Mixtures in Water
Two kinds of mixtures:Homogeneous - has a uniform appearance
throughout. Examples: Milk, fog, sugar and water, smoke, and stirred up dust in the air. Colloid - a homogeneous solution with intermediate
particle size between a solution and suspension. Like milk.
Heterogeneous - is not uniform throughout and consists of visibly different substances. Examples: India ink, oil and water, sand and water. Suspension - a heterogeneous mixture of larger, visible
particles that will settle out on standing. Like sand and water.T
he
In
org
an
ic C
he
mis
try
of
Wa
ter
Cha
pter
8 P
ages
8-9
to
8-11
Menu Previous Next
8 - 24
Solutions and Mixtures in Water
Water can be part of both homogeneous and heterogeneous mixtures.Water’s polar nature makes it good solvent.Regarding salt, let’s examine why water is a good
solvent.
Salt crystals are held together by ionic bonding. Sodium loses an electron, making it positive. Chlorine gains and electron making it negative. The opposites attract forming salt.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-9 t
o 8-
11
Menu Previous Next
8 - 25
Solutions and Mixtures in Water
Water dissolves salt.Water’s charged ends pull apart - dissociate - the
salt (sodium chloride - NaCl) crystal.Sodium and chlorine become charged particles -
ions.
Salt - sodium chloride - NaCl in its crystal or solid state.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-9 t
o 8-
11
Menu Previous Next
8 - 26
Solutions and Mixtures in Water
Water dissolves salt.The positive sodium ion is attracted to the
negative oxygen side of the water molecule.The negative chlorine ion is attracted to the
positive hydrogenside of thewater molecule.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-9 t
o 8-
11
Menu Previous Next
8 - 27
Salts and Salinity
Salinity refers to sodium chloride and many other salts dissolved in seawater.
Salinity includes the total quantity of all dissolvedinorganic solids in seawater (ions).
Dissolved salts includes sodium chloride and everything else.
Scientist’s measure salinity in various ways – current method uses how well water conducts electricity.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Cha
pter
8 P
ages
8-1
1 to
8-1
2
Menu Previous Next
8 - 28
Salts and Salinity
Salinity is expressed in parts per thousand (‰). The ocean’s average salinity is 35, meaning 35‰ or
35g/kg. Variations as small as 0.01 are of importance to
oceanographers. The ocean’s salinity varies from near zero at river
mouths to more than 40‰ in confined, arid regions. The proportion of the different dissolved salts
never change, only the relative amount of water.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Cha
pter
8 P
ages
8-1
1 to
8-1
2
Menu Previous Next
8 - 29
The Colligative Properties of Seawater
Colligative properties are properties of a liquid that may be altered by the presence of a solute and are associated primarily with seawater.Pure water doesn’t have colligative properties.
Fresh water, with some solutes, can have colligative properties to some degree.
The strength of the colligative properties depends on the quantity of solute.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Cha
pter
8 P
age
8-13
Menu Previous Next
8 - 30
The Colligative Properties of Seawater
The colligative properties of seawater include:Raised boiling point. Seawater boils at a higher
temperature than pure fresh water.Decreased freezing temperature. As salinity
increases, water resists freezing (why salt is put on a road during ice/snow storms).
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Cha
pter
8 P
age
8-13
Menu Previous Next
8 - 31
The Colligative Properties of Seawater
The colligative properties of seawater include:Ability to create osmotic pressure. Liquids flow
or diffuse from areas of high concentration to areas of low concentration until the concentration equalizes.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Osmosis occurs when this happens through asemi-permeable membrane, such as a cell wall.Because it contains dissolved salts, water in seawaterexists in lower concentration than in fresh water.
Cha
pter
8 P
age
8-13
Menu Previous Next
8 - 32
The Colligative Properties of Seawater
The colligative properties of seawater include:Electrically conductive. Ability to conduct an
electrical current. A solution that can do this is called an electrolyte.
Decreased heat capacity. Takes less heat to raise the temperature of seawater.
Slowed evaporation. Seawater evaporates more slowly than fresh due to the attraction between ions and water molecules.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Cha
pter
8 P
age
8-13
Menu Previous Next
8 - 33
The Principle of Constant Proportions
In seawater no matter how much the salinity varies, the proportions of several key inorganic elements and compounds do not change. Only the amount of water and salinity changes. This constant relationship of proportions in
seawater is called the principle of constant proportions.
This principle does not apply to everything dissolved in seawater – only the dissolved salts.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
e 6-
14
Menu Previous Next
8 - 34
Dissolved Solids in Seawater
Next to hydrogen and oxygen, chloride and sodium are the most abundant chemicals in seawater.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
e 8-
14
Menu Previous Next
8 - 35
Determining Salinity, Temperature,and Depth
If you know how much you have of any one seawater chemical, you can figure out the salinity using the principle of constant proportions.
Chloride accounts for 55.04% of dissolved solids – determining a sample’s chlorinity is relatively easy.
The formula for determining salinity is based on the chloride compounds:
salinity ‰ = 1.80655 x chlorinity ‰ Sample of seawater is tested at 19.2‰ chlorinity:
salinity ‰ = 1.80655 x 19.2‰ salinity ‰ = 34.68‰
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-14
to 8
-16
Menu Previous Next
8 - 36
Determining Salinity, Temperature,and Depth
Most commonly, salinity is determined with a salinometer.It determines the electrical conductivity of the water.
An important tool to measure the properties of seawater are the Argo floats - an array of 3,000 free-drifting floats.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Salinometer Argo Float
Cha
pter
8 P
ages
8-1
4 to
8-1
6
Menu Previous Next
8 - 37
Determining Salinity, Temperature,and Depth
Another tool is the conductivity, temperature, and depth (CTD) sensor. The CTD profiles temperature and salinity with depth.
Another less accurate way to determine salinity is with a refractometer.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
CTD
Sensor
RefractometerCha
pter
8 P
ages
8-1
4 to
8-1
6
Menu Previous Next
8 - 38
A source of sea salts appears to be minerals and chemicals eroding and dissolving into fresh water flowing into the ocean.
Waves and surf contribute by eroding coastal rock. Hydrothermal vents change
seawater by adding some materials while removing others.
Scientists think these processes all counterbalance so the average salinity of seawater remains constant.
The ocean is said to be in chemical equilibrium.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-16
to 8
-18
Why the Seas Are Salty
Menu Previous Next
8 - 39
Salinity, Temperature, and Water Density
Most of the ocean surface has average salinity, about 35‰. Waves, tides, and currents mix waters to make them more uniform.
Precipitation and evaporation have opposite effects on salinity. Rainfall decreases salinity by adding fresh water. Evaporation increases salinity by removing fresh water. Freshwater input from rivers lowers salinity. Abundant river input and low evaporation results in salinities
well below average.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-18
to 8
-19
Menu Previous Next
8 - 40
Salinity, Temperature, and Water Density
Salinity and temperature also vary with depth.Density differences causes water to separate into
layers.High-density water lies beneath low-density water.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-18
to 8
-19
Menu Previous Next
8 - 41
Salinity, Temperature, and Water Density
Water’s density is the result of its temperature and salinity characteristics: Low temperature and high salinity are features of high-
density water. Relatively warm, low-density surface waters are separated
from cool, high-density deep waters by the thermocline, the zone in which temperature changes rapidly with depth.
Salinity differences overlap temperature differences and the transition from low-salinity surface waters to high-salinity deep waters is known as the halocline.
The thermocline and halocline together make the pycnocline, the zone in which density increases with increasing depth.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-18
to 8
-19
Menu Previous Next
8 - 42
Salinity, Temperature, and Water Density
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
Global Salinity
Cha
pter
8 P
ages
8-1
8 to
8-1
9
Menu Previous Next
8 - 43
Acidity and Alkalinity
pH measures acidity or alkalinity. Seawater is affected by solutes. The relative
concentration of positively charged hydrogen ions and negatively charged hydroxyl ions determines the water’s acidity or alkalinity. It can be written like this:
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-20
to 8
-22
Menu Previous Next
8 - 44
Acidity and Alkalinity
Acidic solutions have a lot of hydrogen ions (H+), it is considered an acid with a pH value of 0 to lessthan 7.
Solutions that have a lot of hydroxyl ions (OH-) are considered alkaline. They are also called basic solutions. The pH is higher than 7, with anything over 9 considered a concentrated alkaline solution.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-20
to 8
-22
Menu Previous Next
8 - 45
Acidity and Alkalinity
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-20
to 8
-22
Menu Previous Next
8 - 46
Acidity and Alkalinity
pH can be measured chemically or electronically. Pure water has a pH of 7 - neutral pH. Seawater pH ranges from 7.8 to 8.3 - mildly alkaline. Ocean’s pH remains relatively stable due to buffering.
A buffer is a substance that reduces the tendency of a solution to become too acidic or alkaline.
Seawater is buffered primarily by carbon dioxide.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-20
to 8
-22
Menu Previous Next
8 - 47
Acidity and Alkalinity
Seawater is fairly stable, but pH changes withdepth because the amount of carbon dioxidetends to vary with depth.
Shallow depths have less carbon dioxidewith a pH around 8.5.
Shallow depths have the greatest density of photosynthetic organisms which use the carbon dioxide, making the water slightly less acidic.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-20
to 8
-22
Menu Previous Next
8 - 48
Acidity and Alkalinity
Middle depths have more carbon dioxide andthe water is slightly more acidic with a lower pH.More carbon dioxide present from the respiration
of marine animals and other organisms, which makes water somewhat more acidic with a lower pH.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-20
to 8
-22
Menu Previous Next
8 - 49
Acidity and Alkalinity
Deep water is more acidic with no photosynthesisto remove the carbon dioxide.At this depth there is less organic activity, which
results in a decrease in respiration and carbon dioxide. Mid-level seawater tends to be more alkaline.
At 3,000 meters (9,843 feet) and deeper, the water becomes more acidic again.This is because the decay of sinking organic
material produces carbon dioxide, and there are no photosynthetic organisms to remove it.
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-20
to 8
-22
Menu Previous Next
8 - 50
Acidity and Alkalinity
Th
e I
no
rga
nic
Ch
em
istr
y o
f W
ate
r
The variation of pH and total dissolved inorganic carbon with depth.
Cha
pter
8 P
ages
8-2
0 to
8-2
2
Menu Previous Next
8 - 51
The Organic Chemistryof Water
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-23
to 8
-30
Menu Previous Next
8 - 52
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-23
to 8
-24
Biogeochemical Cycles
Organic chemistry deals mainly with chemical compounds consisting primarily of carbon and hydrogen.
Inorganic compounds such as dissolved sea salts account for the majority of dissolved solids in seawater.
Dissolved organic elements also interact with organisms on a significant scale.These elements are crucial to life and differ from
the sea salts in several ways.
Menu Previous Next
8 - 53
Biogeochemical Cycles
Proportions of organic elements in seawater differ from the proportions of sea salts because:The principle of constant proportions does not
apply to these elements.These nonconservative constituents have
concentrations and proportions that vary independently of salinity due to biological and geological activity.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-23
to 8
-24
Menu Previous Next
8 - 54
Biogeochemical Cycles
All life depends on material from the nonliving part of the Earth.The continuous flow of elements and compounds
between organisms (biological form) and the Earth (geological form) is the biogeochemical cycle.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-23
to 8
-24
Menu Previous Next
8 - 55
Biogeochemical Cycles
Organisms require specific elements and compounds to stay alive.Aside from gases used in respiration or
photosynthesis, those substances required for life are called nutrients. The primary nutrient elements related to seawater
chemistry are carbon, nitrogen, phosphorus, silicon, iron, and a few other trace metals.
Not all elements and compounds cycle at the same rate. The biogeochemical cycle of the various nutrients affects
the nature of organisms and where they live in the sea.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-23
to 8
-24
Menu Previous Next
8 - 56
Carbon
Carbon is the fundamental element of life. Carbon compounds form the basis for chemical
energy and for building tissues. The seas have plenty of carbon in several forms. It
comes from:Carbon dioxide in the air.Natural mineral sources - such as carbonate
rocks.Organisms - excretion and decomposition.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-24
to 8
-26
Menu Previous Next
8 - 57
Carbon
Carbon cycle.The movement ofcarbon betweenthe biosphereand the nonlivingworld is described
by the carbon cycle.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-24
to 8
-26
Menu Previous Next
8 - 58
Nitrogen
Nitrogen is another element crucial to life on Earth. Organisms require nitrogen for organic
compounds such as protein, chlorophyll, and nucleic acids.
Nitrogen makes up about 78% of the air and 48% of the gases dissolved in seawater.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-26
to 6
-27
Menu Previous Next
8 - 59
Nitrogen
Gaseous nitrogen must be converted to a chemically usable form before it can be used by living organisms.
Bacteria “fixes” nitrogen from the air into usable compounds - nitrate, nitrite and ammonium.
In these forms, autotrophs take up the nitrogen and incorporate it into their systems as protein.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-26
to 6
-27
Menu Previous Next
8 - 60
Nitrogen
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
r
The nitrogen cycle.Bacteria and humanscarry out many of theimportant steps of thenitrogen cycle.The cycle has fourstages: Assimilation,Decomposition,Nitrification,Denitrification.
Cha
pter
8 P
ages
8-2
6 to
6-2
7
Menu Previous Next
8 - 61
Phosphorus and Silicon
Phosphorus is another element important to life because it is used in the ADP/ATP cycle, by which cells convert chemical energy into the energy required for life.Phosphorus combined with calcium carbonate is a
primary component of bones and teeth.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
e 8-
28
Menu Previous Next
8 - 62
Phosphorus and Silicon
The phosphorus cycle.Dissolved phosphorous iscarried to the sea byrunoff and leaching fromland. Phosphorus is usedby plants, then recycledthrough animals until it isreleased from wasteand decay.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
e 8-
28
Menu Previous Next
8 - 63
Phosphorus and Silicon
Silicon is used similarly by some organismsin the marine environment (including diatomsand radiolarians) for their shells and skeletons.Silicon exists in these organisms
as silicon dioxide, called silica.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
e 8-
28
Menu Previous Next
8 - 64
Iron and Trace Metals
Iron and other trace metals fit into the definition of a micronutrient.Micronutrients are substances essential to
organisms in very small amounts.These are essential to organisms for
constructing specialized proteins, including hemoglobin and enzymes. Plants need iron to produce chlorophyll.
Other trace metals used in enzymes include manganese, copper, and zinc.
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
e 8-
29
Menu Previous Next
8 - 65
Chemical Factors thatAffect Marine Life
Th
e O
rga
nic
Ch
em
istr
y o
f W
ate
rC
hapt
er 8
Pag
es 8
-30
to 8
-34
Menu Previous Next
8 - 66
Ch
em
ica
l F
ac
tors
Th
at
Aff
ec
t M
ari
ne
Lif
e
Diffusion and Osmosis
Diffusion is the tendency for a liquid, gas, or solute to flow from an area of high concentration to an area of low concentration.
Cha
pter
8 P
ages
8-3
0 to
8-3
2
Menu Previous Next
8 - 67
Diffusion and Osmosis
Osmosis is diffusion through a semipermeablecell membrane.
Ch
em
ica
l F
ac
tors
Th
at
Aff
ec
t M
ari
ne
Lif
eC
hapt
er 8
Pag
es 8
-30
to 8
-32
Menu Previous Next
8 - 68
Diffusion and Osmosis
This has important implications with respect tomarine animals. Hypertonic - having a higher salt concentration,
and the water will diffuse into the cells. What happens when you put a marine fish into fresh water.
Isotonic - when water concentration inside the cellis the same as the surrounding water outside thecell. There is no osmotic pressure in either direction. Marine fish cells are isotonic.
Hypotonic - having a lower salt concentration than the surrounding water. It is what happens when you put a freshwater fish into seawater.
Ch
em
ica
l F
ac
tors
Th
at
Aff
ec
t M
ari
ne
Lif
eC
hapt
er 8
Pag
es 8
-30
to 8
-32
Menu Previous Next
8 - 69
Diffusion and Osmosis
Ch
em
ica
l F
ac
tors
Th
at
Aff
ec
t M
ari
ne
Lif
e
Hypertonic
Isotonic
Hypotonic
Cha
pter
8 P
ages
8-3
0 to
8-3
2
Menu Previous Next
8 - 70
Active Transport, Osmoregulators,and Osmoconformers
Osmosis through a semipermeable cell membrane is called passive transport.Passive transport moves materials in and out of a
cell by normal diffusion.
Ch
em
ica
l F
ac
tors
Th
at
Aff
ec
t M
ari
ne
Lif
eC
hapt
er 8
Pag
es 8
-32
to 8
-34
Menu Previous Next
8 - 71
Active Transport, Osmoregulators,and Osmoconformers
The process of cells moving materials from low to high concentration is called active transport.Active transport takes energy because
it goes against the flow of diffusion.
Ch
em
ica
l F
ac
tors
Th
at
Aff
ec
t M
ari
ne
Lif
eC
hapt
er 8
Pag
es 8
-32
to 8
-34
Menu Previous Next
8 - 72
Active Transport, Osmoregulators, and Osmoconformers
Marine fish that have a regulation process that allows them to useactive transport to adjust water concentrationwithin their cells are osmoregulators.
Ch
em
ica
l F
ac
tors
Th
at
Aff
ec
t M
ari
ne
Lif
eC
hapt
er 8
Pag
es 8
-32
to 8
-34
Menu Previous Next
8 - 73
Active Transport, Osmoregulators, and Osmoconformers
Marine organisms that have their internal salinity rise and fall along with the water salinity are osmoconformers.
Ch
em
ica
l F
ac
tors
Th
at
Aff
ec
t M
ari
ne
Lif
eC
hapt
er 8
Pag
es 8
-32
to 8
-34