Transcript 5.1-MB-EE.trophiclevels

Ocean Ecosystem
Marine Biology
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Warm Up
1. Explain the role of the following organisms:
A.
B.
C.
Carnivore
Herbivore
Producer
2. What is the difference between a predator
and a prey animal?
3. How is an ecosystem affected if many of the
top predators are killed by humans?
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Boiling Water
What temperature does water boil at?
How hot do hydrothermal vents get?
Could you touch the water in a hydrothermal
vent? Why or why not?
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What is an ecosystem?
System = regularly interacting and
interdependent components forming a
unified whole
Ecosystem = an ecological system;
= a community and its physical environment
treated together as a functional system
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Living and Nonliving Components
of an Ecosystem
1.
Make a list of all the LIVING components that
live in the ecosystem surrounding our school.
2.
Make a list of all the NON LIVING components
that live in the ecosystem surrounding our
school.
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Ecosystem Review
Ecosystem:
“Any area of nature that includes living
organisms and non-living substances that
interact to produce and exchange of materials
between living and non-living parts is an
ecological system or ecosystem.” (E.P.Odum)
Ecosystems consist of 4 components: abiotic,
producers, consumers, and decomposers;
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Ecosystem Review
Biotic Components of the Ecosystem
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plants
animals
bacteria
Abiotic Components of the Ecosystem
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geological

basin shape, size, & topography
physical

temperature, currents, pressure, light)
chemical

carbon, nitrogen, phosphorus, oxygen, salinity, trace metals,
vitamins
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The Ocean Ecosystem
•
The ocean water column can be separated into 2 distinct zones: the surface zone and the
deep zone
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Surface zone
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extends down to about 100- 300 meters
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well mixed
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known as the “mixed layer”
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includes the photic zone
2.
Deep zone
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the rest of the water column
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dark and cold with much less productivity
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includes the aphotic zone

the pycnocline forms a physical barrier between the surface and deep zones
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Biozones
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Shelf Versus Basin
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Autotrophs and Heterotrophs
• There are two types of organisms in any given
ecosystem: autotrophs and heterotrophs
 autotrophs make their own food
– they ‘fix’ CO2 during photosynthesis
– autotrophs form the base of the food web and
are ultimately responsible for all life in the
world’s oceans
– marine examples include phytoplankton,
cyanobacteria, and sulfide oxidizing bacteria (i.e.
at hydrothermal vents)
– phytoplankton are the most abundant primary
producers in the oceans
6 CO2 + 12 H20
C6H12O6 + 6 H2O + 6 O2
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Hydrothermal vents –
‘primary production’ is done
by a type of extremophile,
that is, a type of
microorganism that can
thrive under extreme env.
conditions (temp > 80° C or
below 90° C); these
extremophiles are also
chemoautotrophs – they use
hydrogen and sulfur
compounds as sources of
energy (with or without
oxygen) (chemosynthesis);
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HYDROTHERMAL VENTS AND
CHEMOSYNTHETIC
BACTERIA
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Autotrophs and Heterotrophs
– heterotrophs consume food (organic matter) that has
already been produced
 they make energy (ATP) from the breakdown of
organic compounds during cellular respiration
 when there is no light (i.e. at night or in deeper
waters) phytoplankton and cyanobacteria respire
the organic compounds that they produced during
photosynthesis
 examples of marine heterotrophs include all marine
animals and most marine bacteria
C6H12O6 + 6 O2
6 CO2 + 6 H2O + ATP
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Photo from: Science.nasa.gov
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Hydrothermal Vents
• Video on hydrothermal vents shallow in the
Sea of Cortez @
http://player.discoveryeducation.com/index.cf
m?guidAssetId=BE1B3967-DEA7-4519-AFFF498BBB7EE750&blnFromSearch=1&productc
ode=US
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Independent Research
READ PAGES 402-403 FEATURES OF THE RIFT ZONE
1.
2.
3.
4.
5.
6.
7.
What is the rift?
Why is the rift zone of special interest to oceanographers?
Explain how the ocean basin was created.
Explain how black smokers work.
What is a hydrothermal vent?
How hot is the water that comes out of the hydrothermal vents?
What happened to the first thermometer that was used near the
hydrothermal vents?
8. Explain the YEAR and SIGNIFICANCE of the Alvin submersable.
9. What Marine Biology careers are linked to this type of
exploration?
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HSA Public Release Questions
Analyze the
hydrothermal vent
picture in order to
identify different
ecological roles
within this
ecosystem.
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Trophic Levels
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ENERGY FLOW IN ECOSYSTEMS
All organisms require energy,
for growth, maintenance, reproduction, locomotion,
etc.
Hence, for all organisms there must be:
A source of energy
A loss of usable energy
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Types of energy
heat energy
mechanical energy (+gravitational energy,
etc.)
chemical energy = energy stored in
molecular bonds
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Transformations of energy
How is solar energy converted to chemical energy?
How does this process influence life as we see it on
earth?
The transformations of energy from solar radiation
to chemical energy and mechanical energy and
finally back to heat are a traditional topic of
Ecosystem Ecology.
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An ecosystem has abiotic and biotic
components:
ABIOTIC components:
Solar energy provides practically all the
energy for ecosystems.
Inorganic substances, e.g., sulfur, boron,
tend to cycle through ecosystems.
Organic compounds, such as proteins,
carbohydrates, lipids, and other complex
molecules, form a link between biotic and
abiotic components of the system.
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BIOTIC components:
The biotic components of an ecosystem can
be classified according to their mode of
energy acquisition.
In this type of classification, there are:
Autotrophs
and
Heterotrophs
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Autotrophs
Autotrophs (=self-nourishing) are called primary
producers.
Photoautotrophs fix energy from the sun and
store it in complex organic compounds
(= green plants, algae, some bacteria)
light
simple
inorganic
compounds
photoautotrophs
complex
organic
compounds
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Plankton include plants (phytoplankton) and
animals (zooplankton). More than 90% of marine
plants are algae and most are unicellular and
microscopic.
To photosynthesize (produce organic material
from inorganic matter and sunlight) plants must
remain within the photic zone.
Diatoms are single-celled plants enclosed in a
siliceous frustrule (shell) that is shaped like a
pillbox.
Dinoflagellates are single-celled plants with two
whip-like tails (flagella).
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Chemoautotrophs (chemosynthesizers) are
bacteria
that oxidize reduced inorganic substances
(typically sulfur and ammonia compounds)
and produce complex organic compounds.
oxygen
reduced
inorganic
compounds
chemoautotrophs
complex
organic
compounds
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Chemosynthesis near hydrothermal vents
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Other chemoautotrophs:
Nitrifying bacteria in the soil under our feet!
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Heterotrophs
Heterotrophs (=other-nourishing) cannot
produce their own food directly from
sunlight+ inorganic compounds. They
require energy previously stored in complex
molecules.
heat
complex
organic
compounds
heterotrophs
simple
inorganic
compounds
(this may include several steps, with
several different types of organisms)
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Heterotrophs can be grouped as:
consumers
decomposers
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Consumers feed on organisms or particulate
organic matter.
Decomposers utilize complex compounds in
dead protoplasm.
Bacteria and fungi are the main groups of
decomposers.
Bacteria are the main feeders on animal
material.
Fungi feed primarily on plants, although
bacteria also are important in some plant
decomposition processes.
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The Laws of Thermodynamics
Energy flow is a one-directional process.
sun---> heat (longer wavelengths)
FIRST LAW of THERMODYNAMICS:
Energy can be converted from one form to
another, but cannot be created or destroyed.
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Energy flow
Simple!
heat
Producers
Consumers
Decomposers
heat
This pattern of energy flow among different
organisms is the TROPHIC STRUCTURE of an
ecosystem.
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It is useful to distinguish different types of
organisms within these major groups,
particularly within the consumer group.
Consumers
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Terminology of trophic levels
We can further separate the TROPHIC LEVELS,
particularly the Consumers:
Producers (Plants, algae, cyanobacteria; some
chemotrophs)--capture energy, produce complex
organic compounds
Primary consumers--feed on producers
Secondary consumers--feed on primary consumers
Tertiary consumers--feed on secondary consumers
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More trophic levels:
Detritivores--invertebrates that feed on organic
wastes and dead organisms (detritus) from all
trophic levels
Decomposers--bacteria and fungi that break
down dead material into inorganic materials
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More Trophic Levels
Producers = plants etc. that capture energy
from the sun
Herbivores = plant-eaters
Carnivores = animal-eaters
Omnivores--eat both animals and plants
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Together, these groups make up a FOOD CHAIN
E.g., grass, rabbit, eagle
Carnivore
Herbivore
Producer
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Carnivores
Carnivores can be further
divided into groups:
quaternary carnivore
tertiary carnivore
secondary carnivore
primary carnivore
(top)
The last carnivore in a
chain, which is not
usually eaten by any
other carnivore, is often
referred to as the
top carnivore.
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Food
chains
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Food
chains
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Food
chains
Rarely are things as simple as grass, rabbit,
hawk, or indeed any simple linear sequence
of organisms.
More typically, there are multiple interactions,
so that we end up with a FOOD WEB.
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Food
chains to
Food Web
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Energy transfers among trophic
levels
How much energy is passed from one trophic
level to the next?
How efficient are such transfers?
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Biomass--the dry mass of organic material
in the organism(s).
(the mass of water is not usually included,
since water content is variable and
contains no usable energy)
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Primary productivity
Primary productivity is the rate of energy
capture by producers.
= the amount of new biomass of producers, per
unit time and space
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Ecological pyramids
The standing crop, productivity, number of
organisms, etc. of an ecosystem can be
conveniently depicted using “pyramids”,
where the size of each compartment
represents the amount of the item in each
trophic level of a food chain.
carnivores
herbivores
producers
Note that the complexities of the interactions in a food
web are not shown in a pyramid; but, pyramids are
often useful conceptual devices--they give one a sense
of the overall form of the trophic structure of an
ecosystem.
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Energy Pyramid
A pyramid of energy depicts the energy flow, or
productivity, of each trophic level.
Due to the Laws of Thermodynamics, each higher
level must be smaller than lower levels, due to
loss of some energy as heat (via respiration)
within each level.
Energy flow in :
carnivores
herbivores
producers
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Biomass Pyramid
If the biomass produced by a trophic level is
summed over a year (or the appropriate
complete cycle period), then the pyramid of
total biomass produced must resemble the
pyramid of energy flow, since biomass can be
equated to energy.
Yearly biomass production
(or energy flow) of:
carnivores
herbivores
producers
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Independent Research
Page 523 Marine Science
Look at the food chain.
1. In figure 21-6, explain how this small
community would be affected if the herring
was overfished.
2. In figure 21-7, place the organisms into a
trophic level pyramid.
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Independent Research
Page 523 Marine Science
Look at the food chain.
1. In figure 21-6, explain how this small
community would be affected if the herring
was overfished.
2. In figure 21-7, place the organisms into a
trophic level pyramid.
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HSA Public
Release
Test Yourself!
Use the arrows to explain
what eats what:
_________ eat __________
_________ eat___________
Name all of the producers
you see in this picture.
Name all of the consumber
that you see in this
picture.
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