Oceanography
Lecture Notes Outline
Definition
of Life – What Does it Mean to be "Alive"?
Biogeochemical Cycles – Carbon, Nitrogen, and
Others
Physical
Controls Affecting Life – Matter, Energy, and the "Zone"
Biological
Controls Affecting Life – Life's Affect on Life
Evolution of Marine Life – Change through Time
Classification
of Marine Life – Taxonomy and Phylogenies
Classification of Marine Habitats – The
Various Living Zones
II. Defining Life
A.
Precise Formal Definition is Elusive
1. A definition of life must have the
following criteria:
·
Highly organized
structure(s)
·
Low-entropy state
·
Capture, store,
transmit, and transform energy
·
Capable of
reproducing
·
Adapt to the
environment
·
Change through
time
2. The intimate exchange of matter and energy between
living and nonliving systems makes it difficult in many
cases to draw a line where one stops and the other starts
3. The essential difference between living and
nonliving
systems is the
living system's:
·
Ways of utilizing
energy to move, grow and maintain
·
Functioning cells
·
Ability to
reproduce
o
Generate new
entities with similar cells
B.
Life and Matter
1. All living systems on Earth
contain matter
·
Consist of 23 of
107 known chemical elements
·
Only four of
these make up nearly 99% of the mass of all
living things:
o
Oxygen
o
Carbon
o
Hydrogen
o
Nitrogen
2. The 23 elements in living things combine
to form several
classes of biochemicals essential to all life. They are:
·
carbohydrates
(sugars, starches, and cellulose)
·
lipids
(fatty acids, fats, waxes, and oils)
·
proteins
and enzymes
·
nucleic acids
3.
The across-the-board sameness and occurrence of all
the above substances
in all living things on Earth strongly
suggest a common
origin (ancestor) to all groups of life
C.
Life and Energy
1. All living systems capture,
store, transfer, and transform
energy
2.
Living systems not able to create energy - only change it
3. Different
living systems have unique variations in how
they capture,
store, transfer, and transform energy
·
Photosynthesis of
plants
·
Chemosynthesis of
certain bacteria
4. Organisms utilize energy input to both move,
grow and
maintain their highly
ordered structures
·
Temporarily
delays Second Law of thermodynamics
·
Work against entropy = lowering degree of disorder
5.
Life derives its energy principally from the sun
·
Directly
- Photosynthesizers (autotrophs)
·
Indirectly
- Consume autotrophs (heterotrophs)
·
There are a few
exceptions
o
Deep sea vent
bacteria
6.
Typical path of energy in living systems
·
Sunlight ▬► chemical energy ▬► kinetic energy ▬► heat
III. Biogeochemical Cycles
A. Biogeochemical cycles defined
1. The movement of the atoms and small molecules (that
life depends upon) between living and nonliving systems
2. The atoms and small molecules that life depends
upon
(making up the living tissue of organisms) are either:
o
Always on the
move in and out of living systems
o
Locked away in
the Earth
Ø Sediments
Ø Deeply buried rock
B.
There are Several Major Biogeochemical Cycles
Ø Carbon
Ø Nitrogen
Ø Silicon
Ø Phosphorus
Ø Iron
Ø Trace Metals
C. The Carbon Cycle
1. The largest of all
cycles in terms of mass (see fig. 13.3)
·
Reservoirs
include life, land, ocean and atmosphere
·
Forms include
carbonate sediment and rock, hydrocarbon
fuels, gaseous CO2 in the atmosphere and
dissolved gas in the
ocean, in bodies of organisms, dissolved organic carbon, and
dissolved
inorganic carbon-based ions, like carbonic acid
2. Carbon is the basic
building block of all life on Earth
·
Ability to form
long chains to which other atoms can attach
3. Carbon enters the atmosphere
and ocean in several ways
·
Life respiration
·
Volcanic eruption
·
Uplift,
weathering, and erosion of carbonate rock
·
Burning of fossil
fuels
4. Carbon initially enters the
living world in one main way:
·
Carbon fixation
by photosynthesis
·
Either from the
atmosphere or ocean
5. Carbon moves through the living
world in several ways:
·
Moving within a
living organism
o
Incorporated into
cells of organism for growth
§
45% of total used
for organism growth
o
Respiration
(converted to end product - CO2)
§
45% of total used
in respiratio
o
Excreted as
dissolved organic carbon (DOC)
§
10% of total lost
to waste as DOC
·
Moving between
living organisms
o Plant matter eaten by animals
o
Animals eat other
animals
6. The dissolved
organic carbon is taken in by bacteria
7. Dead falling organic
matter in ocean mostly converted to
CO2
by respirating bacteria who consume detritus
8. The less than 1% of
organic detritus not converted to
CO2 by
bacteria in the water column or ocean bottom is
incorporated
into carbonate sediment and buried
9. Buried carbonate
sediment and rock in ocean bottom
will at some point
get recycled back into the life cycle by
·
Uplift,
weathering and erosion
· Volcanic gas
release of melted subducted sediments
D. The Nitrogen Cycle
1. The second largest of all cycles in terms of
mass
·
See figure 13.4
·
Reservoirs
include life, land, ocean and atmosphere
·
Forms include
nitrate rocks and sediment, organic matter,
gaseous N2 in the atmosphere, dissolved N2 in
the ocean, in
bodies of organisms, dissolved organic nitrogen, and
dissolved
inorganic nitrogen-based ions like NH4+, NO3-,
and
NO2-
2. Nitrogen is a basic
building block of all life on Earth
·
Critical element
in production of proteins, nucleic aids, and
chlorophyll
3. Nitrogen enters the
atmosphere and ocean as follows:
·
Volcanic eruption
·
Uplift,
weathering, and erosion of nitrogen material
4. Nitrogen initially enters the
living world in one main way:
·
Fixation of nitrogen by special organisms
·
Either from the
atmosphere, land, or ocean
5. Nitrogen fixation is the process by which nitrogen is
bound
to either oxygen or hydrogen into a usable form
by
living organisms
6. Usable nitrogen moves
through the living world:
·
Moving within a
living organism
o
Incorporated into
cells of organism for growth
o
Denitrifying
bacteria use reduced forms of nitrogen
ions for respiration
o
Excreted as
dissolved organic carbon (DON)
·
Moving between
living organisms
o Plant matter eaten by animals
o
Animals eat other
animals
7. The nitrogen cycle
is shown in Figure 13.4 (page 324)
E. The Phosphorus Cycle
1. The phosphorous cycle is relatively simple
·
Cycles in three
loops (see Fig, 13.5)
·
Reservoirs
include life, land, and ocean
·
Forms include
phosphate rocks and sediment, organic
matter, dissolved PO4 in the ocean, and in bodies
of
organisms
2. Phosphorus is a
basic building material of all life on
Earth
·
Critical element
in binding of nucleic aids
·
Used in the
molecules that fuel cells
·
Goes into calcium
phosphate for bones, teeth, nails,
and shells
3. Phosphorus enters the ocean
as follows:
·
Volcanic eruption
via precipitation and rivers
·
Uplift,
weathering, and erosion of phosphorous material
via rivers
4. Phosphorus has three
different cycles
·
Fast cycle -
direct life-death-life
o
Days to years
·
Slower cycle -
life-death-ocean
o
Hundreds of years
·
Slowest cycle -life-death-Earth
o
Millions of years
F. The Silica Cycle
1. Very similar to phosphorus cycle
2. Silica used in connective tissue and marine shells
G. The Iron Cycle and Other Trace
Elements
1. Similar to phosphorus and silica cycles
·
Simple loops
·
Reservoirs
include land, ocean, and organisms
·
Forms include
iron-rich rock and sediment, iron oxides,
dissolved iron, and iron in organisms
2. Iron is nearly
insoluble seawater
·
Typically very
low concentrations
·
Very reactive in
seawater
·
Easily partitions
into marine sediment
3. Iron concentrations are typically so low that
it becomes
a limiting factor to the
growth of organisms
H. Limiting Factors in the Marine
Environment
1. A limiting factor is
any physical or biological necessity
whose presence in
inappropriate amounts limits the
normal function of
an organism
·
Element or
nutrient
·
Sunlight
·
Temperature
·
Proper pH
·
Salinity
IV. Physical Factors Affecting Marine Life
A. The
Ocean is Marine Life’s Support System
1.
Depend on the oceans chemical constituents
2.
Depend on stable physical conditions
3.
Very intimate interrelationship between marine life and
its ocean environment
4.
The various chemical and physical aspects that marine
life rely on to survive are termed physical factors
5. The most critical
physical factors for marine life are:
Ø
Sunlight
Ø
Temperature
Ø
Salinity
Ø
Dissolved nutrients and gases
Ø
pH balance
Ø Hydrostatic pressure
B. Sunlight is Essential to Most
Marine Life
1. Absolutely essential to photosynthesizing organisms
2.
Transparency of ocean water to sunlight allows
photosynthesis
to occur down to over 100 meters deep
3.
Differential absorption of various wavelengths of light
with depth
4.
Depth of water penetration also limited by particulate
matter in the
water column
5.
Latitude and atmospheric cloud cover also affect amount
of sunlight penetrating ocean surface
C. Water Temperature
1. Ocean temperatures
vary with latitude and depth
Ø
Vast bulk of ocean’s water is near freezing
Ø
Only tropical and temperate surface waters get
warmer
Ø See Figure 13.12 for
seawater temp variations
2. Great majority of
marine organisms are “cold-blooded”
Ø Cold-blooded = ectothermic or poikilothermic
Ø Warm-blooded = endothermic or
homeothermic
3. Rates at which
biochemical reactions take place depend
on seawater
temperature
Ø Metabolic rate roughly
doubles with a 10°C (18°F)
increase in sea temperature
Ø Warmer water ectothermic organisms have higher
metabolic rates than their colder water cousins
4. All marine organisms have external
temperature ranges
Ø Endothermic organisms have
fairly narrow ranges
Ø Ectothermic organisms have wider ranges
D. Salinity
1. Ocean salinity can vary tremendously from place
to place
Ø Coastal areas near rivers
Ø Isolated, high evaporative
seas
Ø Less variable with depth
Ø Slightly saltier with depth
2.
Salinity levels affect cell membranes of organisms
Ø Changing salinity can damage
cells membranes
Ø Affects internal cell
salt-water balance
Ø Also affects buoyancy of an
organism
F. Dissolved Nutrients and Gases
1. Dissolved nutrients and certain gases are
required by
organisms to stay alive – they include:
Ø Nitrogen (NO3-)
Ø Phosphorus (PO43-)
Ø Calcium
Ø Silica
Ø Iron
Ø Trace elements
Ø Oxygen
Ø Carbon dioxide
2.
The above necessary dissolved nutrients and gases are
generally in short
or limited supply in much of the ocean
Ø Exception is CO2,
which is rather abundant
Ø These materials are depleted
during times of rapid
growth and/or
reproduction cycles
3. Rapid
photosynthesis depletes CO2 , but
increases O2
4. Rapid
respiration depletes O2, which in turn can cause a
die-off, whereby
decomposition of bodies by bacteria will
further decrease O2 levels,
causing a larger, broad die-off
G. Acid – Base (pH) Balance
1.
Seawater is slightly alkaline
Ø pH averages around 8
2. Variations between 8.5 and 7.0 occur in seawater
Ø Much smaller than that of
soils
Ø Affects dissolved
concentrations of nutrients and gases
H. Hydrostatic Pressure
1. Great hydrostatic
pressure has little to physical effects
on marine life in
ordinary situations
Ø Deep water fish rapidly
hauled to the surface by
fisherman may
experience critical effects
2. Hydrostatic pressure can
affect degree of dissolution of
elements and
gases
I. Importance of Intermixing
Physical Factors
1.
Physical factors are closely interrelated
Ø A change in one factor will
typically cause a
change in one or
more other factors
Ø See chart in Figure 13.13
for an example
V. Biological Factors Affecting Marine Life
A. Biological Factors Defined
1. Biological factors are
aspects of the marine environment
that are generated by
marine organisms, which in turn
affect living marine
organisms
2.
Biological factors include the following:
Ø
Feeding relationships
Ø
Organism (population) density (crowding)
Ø
Organism waste products
Ø Defensive behaviors
VI. Marine Life Adaptations to Marine Conditions
A. Diffusion, Osmosis, and Active
Transport
1. Importance of moving water, food and wastes in an
out
of cells
2. Importance of moving
water, food and wastes in an out
between organism and
environment
B. The Surface-to-Volume Problem
1. Finding the right surface area to volume for both
cells
and the size of
organism for optimum functioning
C. Density and Buoyancy
1. Control of vertical
movement of organism in water
column
D. Viscosity – Drag versus turbulence
1. Optimization of
organism body shape for movement
through seawater
2. Small animals have a
drag problem
3. Large animals have a
turbulence problem
E. Water Movement
1. Ocean Currents
Ø Pelagic drifting organisms
Ø Vertical movements
2. Tidal fluctuations
3. Wave and surf action
VII. Evolution of Life in the Ocean
A. Observations of Present Day Life
on Earth
1. There is a great
diversity of life forms
Ø Millions of different species are already known
Ø Filling millions of different environmental niches
2. There are a great
number of similarities amongst life
Ø Obvious
o
External
structures and functions (body parts)
Ø Hidden
o
Internal design
(cellular and genetic levels)
B. Observations of Ancient Life in
Earth's Rock Record
1. First signs of life
found in rock almost 4 billion years old
2. Earliest life was
very simple and primitive
Ø Bacteria
Ø Cyanobacteria
3. First animals with
hard parts showed up around 500
millions years
ago
Ø Exclusively marine animals
Ø Most of these organisms have been long extinct
o
Archeocyathids
o
Trilobites
o
Various shelled
invertebrates
4. There has been a great diversity of
life ancient forms
Ø Hundreds of thousands of different species documented
Ø Filling many different environmental niches
5. Number of
similarities amongst ancient life
Ø Obvious
o
External
structures and functions (body parts)
6. The assemblage of documented ancient
organisms
(now fossils)
living at any given time in the past is
totally unique to
both, earlier or later assemblages of
preserved
ancient life
Ø Shown at any given geographic level - local, regional,
or
global
Ø Most recent fossils found in rock closely resemble the
organisms alive today
Ø Increasingly older fossils are progressively different
Ø Systematic disappearance (extinction) of old forms
Ø Systematic appearance (speciation) of new forms
Ø Complexity of organisms has increased with time
o Prokaryotes to eukaryotes
o Single-celled to multi-celled
organisms
o Invertebrates to vertebrates
o
Fishes to
Amphibians to Reptiles to Mammals
7. Great extinctions
events happen every 50 to 100 MY
Ø Each event wiped out a quarter to half of all species
Ø Extinction events attributed to bolides & eruptions
8. Extinction events
followed by explosion of new life forms
Ø Uniquely new organisms would fill in new niches or old
niches left open from recently extinct life forms
C. What is Evolution?
1. Evolution
defined:
Ø Change through time
2. Facts about Nature:
Ø
The
Universe has changed through time
Ø
Our
solar system has changed through time
Ø
The physical Earth has changed through time
Ø
Life on Earth has changed through time
3.
Interpretations that Best explain the observed changes:
Ø
The
Big Bang theory
Ø
Theory
of Stellar evolution
Ø
The
Solar System accretion theory
Ø
The
Plate tectonic theory
Ø The theory of Biologic evolution
D.
The Theory of Life Evolution
1. Biologic Evolution defined:
Ø The change in heredity characteristics of groups of
organisms over the
course of generations due to the
combined affects of genetic mutation,
natural selection,
and geographical isolation
2. Charles Darwin is credited with proposing evolution
by
natural selection
3. Natural selection defined:
Ø Greater reproductive success among particular members
of a species
arising from genetically determined
characteristics
that confer an advantage in a particular
environment
4.
Genetic mutation defined:
Ø Inheritable change in the make-up of an organisms
genes
(traits)
Ø Both favorable and unfavorable mutations occur
Ø Favorable mutations are the ones that provide an
organism
with an
environmental advantage
5.
Geographical isolation defined:
Ø Physical barriers to gene flow
o
Mountain ranges
o
Oceans
o
Deserts
Ø Physical barriers come and go with time
o
Plate tectonics
the primary agent
6.
New species emerge when natural selection and genetic
mutation
are able to proceed within a geographically
isolated population
(gene pool) with sufficient time
7.
Opposition to the Theory of Evolution has come mainly from
Christian groups who favor creationism or intelligent
design
Ø
Nonscientific
views based mainly on Bible scripture
VIII. Classification of Marine Life
A. Classification Systems Divide Life Based
Upon Likeness
1. Study of biological
classification is termed taxonomy
2. A classification
system based upon only on gross
external physical and behavioral
similarities is termed
an artificial
system of classification
Ø Example is grouping all life
forms that swim into a single
category or group
Ø List would include humans,
polar bears, seals, whales,
all types of fish, squid, jellyfish, etc
3.
A classification system for living organisms
based upon
on the total
number of structural and biochemical
similarities is termed a natural system of classification
Ø Arranged in an order that is
o Logical
o Systematic
o Hierarchal
Ø Example is grouping of all
types of turtles into a
single category or group, regardless of whether
or not they can swim
4.
A classification system for ancient organisms
based
upon on the
total number of structural similarities is
also considered
a natural system of classification
Ø Arranged in an order that is
o Logical
o Systematic
o Hierarchal
Ø Example is grouping of all
types of ancient
trilobites into a single category or group, based
on unique morphological
characteristics
B. Modern
Natural Classification System of Life Forms
1.
Modern phylogeny is based upon several criteria:
Ø Physical, biochemical, and
genetic structures
Ø Evolutionary relationships
2.
Father of modern biological phylogeny - Carolus
Linnaeus
3. Contains
Six Supreme Categories
Ø Termed Kingdoms
Ø Five are "natural"
o
Archaea
o
Bacteria
o
Fungi
o
Plantae
o
Animalia
Ø One is "unnatural"
o Protista
Ø Study Figure 13.9 and Table 13.2
3.
Further subcategories based on hierarchy
Ø Degree of similarity, complexity, grade, or class
Ø Largest category at the top
o Kingdom
o Very few groups at kingdom level
Ø Smallest category at the bottom
o Species
o Very large number of groups at species level
4. Seven hierarchal subcategories beneath kingdom
Ø Phylum
Ø Subphylum
Ø Class
Ø Order
Ø Family
Ø Genus
Ø Species
Ø See Figure 13.10
5. Naming a specific animal includes two names
Ø Genus
Ø Species
Ø
An animal's scientific name
IX. Classification of Marine Habitats
A. Based Upon Homogeneity of
Environmental Features
1. Classification based on similar sunlight
characteristics
2. Classification based
on similarity in physical location
B. Classification by Sunlight
1. Classification is
based upon the intensity or absence of
sunlight within the ocean water column
2. Photic zone
Ø Uppermost layer of the ocean
that is sunlit
Ø Includes the upper 600
meters of ocean column
Ø Varies in maximum depth
according to location
Ø Region where photosynthesis
takes place
3. Euphotic zone
Ø Upper part of photic zone
Ø Plant production by
photosynthesis exceeds the loss of
carbohydrates by plant respiration
4. Disphotic
zone
Ø Lower part of photic zone
Ø Loss of carbohydrates by
plant respiration exceeds plant
production by photosynthesis
5. Aphotic zone
Ø Lies beneath the disphotic zone
Ø Photosynthesis is
unsustainable or impossible
Ø This dark zone is the
largest region of the ocean
C. Classification by Location
1. Primary division is
between ocean water column and
ocean bottom
Ø Pelagic zone = Open water
Ø Benthic zone = Sea bottom
2. Pelagic zone divided into two subzones:
Ø Neritic zone = near shore
over the continental
shelves
Ø Oceanic zone = Offshore over
deep water
Ø Free-swimming and floating organisms
dwell here
2. Benthic Zone is divided into several subzones
Ø Littoral zone = intertidal
bottom
Ø Sublittoral zone = continental shelf
bottom
seaward of littoral zone
Ø Bathyal zone = Continental slope
and rise bottom
Ø Abyssal zone = Vast true
ocean basin bottom
Ø Hadal zone = super deep
ocean bottom; trenches
Ø Burrowing, attached,
crawling, and swimming
organisms found on or in the bottom
D. Classification of Organisms by Behavior
1. Primary division is
based upon both, the organism’s
ability, or lack of ability, to stay suspended in the
water column
Ø Pelagic = Floating, suspended in
water column
Ø Benthic = Living on or in the
bottom
2. Pelagic organisms divided into two groups
Ø Plankton = suspended; passive-swimmers
Ø Nekton = active swimmers
X. Life In the Ocean Vocabulary - Chapter 13
abyssal zone
active transport
adaptation
Animalia
aphotic zone
Archaea
artificial system of classification
Bacteria
bathyal zone
benthic zone
biogeochemical cycle
biological factor
carbon factor
convergent evolution
Darwin, Charles
denintrifying bacteria
diffusion
disphotic zone
dissolved organic carbon (DOC)
dissolved organic nitrogen (DON)
drag
ectotherm, ectothermic
endotherm, endothermic
energy
entropy
eukaryote
euphotic zone
evolution
hadal zone
hierarchy
hydrostatic pressure
hypertonic
hypotonic
isotonic
kingdoms
limiting factor
Linnaeus, Carolus
littoral zone
mass extinction
metabolic rate
mutation
natural selection
natural system of classification
nekton
neritic zone
nitrifying bacteria
nitrogen cycle
nutrient
oceanic zone
osmosis
pelagic
pelagic zone
photic zone
phylogeny
physical factor
plankton
Plantae
prokaryote
Protista
scientific name
second law of thermodynamics
species
sublitttoral zone
surface-to-volume ratio
taxonomy
theory of evolution
turbulence
viscosity
zone