DO NOW: What do you think is the most important
organism in the oceanic food web?
DO NOW: What is in the picture above? Is it a fish
or a mammal?
What zone do you think it lives in? What does it eat?
The Ocean
The entire body of salt water that covers about 72% of the earth's
surface.
Average salinity – 3.5%
Average pH – 8.179
Oceans
& Their
Names
How many
oceans are
there and
what are
their
names?
Another Look!
Seas
Also large salt water bodies
By definition – landlocked (or almost landlocked) bodies of water
smaller than the great oceans
Examples:
Bering Sea
Mediterranean Sea
Red Sea
What are the
Seven Seas
that sailors
used to refer
to?
Look For the Following Key Ideas
* Energy flows through living systems, but matter is recycled.
* Primary producers, called autotrophs, synthesize glucose by the
process of photosynthesis or chemosynthesis.
* Heterotrophs cannot synthesize glucose, and must consume
autotrophs or other heterotrophs for food.
* Feeding relationships resemble webs.
* Phytoplankton are some of the world’s most important producers;
zooplankton are the most abundant consumers in the ocean.
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Oceanographers divide the
ocean into regions depending
on physical and biological
conditions of these areas.
-Pelagic Zone
-Photic Zone
-Littoral Zones
-Intertidal Zone
-Neritic Zone
-Oceanic Zone
-Benthic Zone
The Five Pelagic Zones of the Ocean
Euphotic & Disphotic Zone
Aphotic
Zone
(“No Light”)
What adaptations might these fish have developed to survive in the different zones?
Aquatic Food Web
Why is it
important
for us to
understand
the oceans
biodiversity
?
Eliminate Just One and name the sequence of events that follows
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10
Primary Producers
Sites to visit: Google Earth, NCDDC.NOAA.gov, AMETSOC.org
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Kelp forests
Kelp forests are one of the ocean’s most productive habitats.
Capture and Flow of Energy
Most of the energy used by marine organisms to make food
comes from the sun.
Photosynthesis is the process used by most producers to convert the
sun’s energy to food energy.
Chemosynthesis is the production of food from inorganic molecules
in the environment.
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13
Capture and Flow of Energy
The flow of energy through living systems.
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14
The Cycling of Matter
The cycling of matter through living systems.
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Feeding Relationships
What terms are used to describe feeding relationships?
Autotrophs – organisms that make their own food, also called
producers.
Heterotrophs - organisms that must consume other organisms for
energy
Trophic pyramid - a model that describes who eats whom
Primary consumers - these organisms eat producers
Secondary Consumers - these organisms eat primary consumers
Top consumers - the top of the tropic pyramid
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Feeding Relationships
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Primary Productivity
Synthesis of organic material from inorganic substances is primary
productivity.
Primary productivity is measured in grams of carbon bound into
organic material per square meter of ocean surface per year, or, more
simply:
gC/m2/yr
Recent studies suggest that total ocean productivity is between
75 gC/ m2/yr and 150 gC/ m2/yr.
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Primary Productivity
Oceanic productivity is measured in gC/ m2/yr.
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Factors That Limit Productivity
What factors could limit primary productivity?
Water
Carbon dioxide
Inorganic nutrients
Sunlight
Since water and carbon dioxide are in good supply in the ocean, the
factors that usually limit primary productivity are inorganic nutrients
and sunlight.
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20
Plankton
Plankton are drifting autotrophs. Plankton is a group of many species,
some photosynthetic and some chemosynthetic. Scientists can collect and
study plankton using plankton nets.
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21
Plankton
What are the major types of phytoplankton?
Diatoms - the dominant and most productive of the photosynthetic
plankton
Dinoflagellates - widely distributed single-celled phytoplankton; use
flagella to move
Coccolithophores and silicoflagellates - small single celled
autotrophs
Nanoplankton and picoplankton - this category encompasses most
other types of plankton, which are very small.
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The Euphotic Zone
The euphotic zone is the site of photosynthetic production.
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Compensation Depth
What is the balance between respiration and photosynthesis at different
depths?
The compensation depth is the “break even” depth. Remember, many
factors affect compensation depth; it is not fixed and will vary between
locations and at different times of day.
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Global Distribution of Plankton
Productivity
The distribution of phytoplankton corresponds to the distribution of
macronutrients. The productivity of plankton varies between the
seasons.
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25
Larger Marine Producers
Some oceanic autotrophs are attached (remember, plankton are
drifters). Attached autotrophs are forms of protists we commonly call
algae, or seaweed. Seaweeds can be classified based on the type of
pigments they have.
Chlorophytes are green due to the presence of chlorophyll and the
lack of accessory pigments.
Phaeophytes are brown. They contain chlorophyll and the secondary
pigment fucoxanthin
Rhodophytes These seaweeds get their red color from the accessory
pigments called phycobilius.
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Larger Marine Producers
Rhodophytes can be encrusting (a) or erect (b).
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Marine Angiosperms
Angiosperms are advanced vascular plants that reproduce with
flowers and seed. Most angiosperms are found on land but a few
species are found in ocean environments.
Sea grasses are found on the coasts. Their seeds are distributed
by water. Seagrasses are very productive as compared to
phytoplankton.
Mangroves are found in sediment rich lagoons, bays and estuaries.
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Marine Angiosperms
Mangroves have distinctive roots that provide anchorage, trap
sediment and protect small organisms.
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Basic Food Chain
Diatoms, and other primary producers, convert the energy from the
sun into food used by the rest of the oceanic community.
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