1. ECOSYSTEMS OF THE OCEAN
SOL 5.6
Biological Characteristics

2. Physical Changes (Depth)
Temperature
Amount of light
Salinity
Pressure
Plant and animal life

3. What is an ecosystem?
An area made up of living organisms and the nonliving things in their environment
Organisms in the ocean have adaptations to help them survive in their ecosystems.

4. The ocean ecosystem is made up of three main zones
The ocean ecosystem is made up of three main zones. These zones are based upon the amount of sunlight each zone receives.

5. SUNLIT ZONE The smallest zone
More than 90% of ocean organisms live here
Receives the most sunlight

6. TWILIGHT ZONE Below the sunlit zone Very little sunlight Cold
High pressure
High salinity
Less food (fewer animals)
Green plants do not grow here

7. MIDNIGHT ZONE Deepest part of the ocean Pitch black (no sunlight)
Freezing
Greatest amount of pressure
Greater than any other place on the Earth’s surface
Covers 90% of the ocean’s space
Least amount of ocean life

8. The ocean is full of organisms and marine life.

10. PLANKTON Tiny organisms that float or drift within the water Two kinds
Phytoplankton
Like plants (need warm temperatures and sunlight)
Make food through photosynthesis
Make most of the oxygen found on Earth
Zooplankton
Tiny animals

11. NEKTON Ocean animals that can swim or move freely in the ocean
The largest portion of familiar animals found in the ocean
Live at different depths
Examples include fish, octopus, whales, eels, and squid

12. BENTHOS Plants and animals that live on the ocean floor of the ocean
Some are attached to the floor
Examples: sea stars, oysters, clams, sea cucumbers, and sea anemones

13. FOOD WEB
Organisms in each zone affect other organisms in that zone and in other zones.

14. FOOD CHAIN
Plants and phytoplankton are on the bottom of all food chains in the ocean.
They make their own food
Use the sun’s energy and nutrients that are in the ocean

15. FOOD CHAIN Zooplankton eat the phytoplankton and plants.
Small fish eat the zooplankton.
Large fish eat the small fish.
When fish die, they sink. Decomposers eat their bodies. (Ex: sea slug, sea worm)
Nutrients float back up into the water.
Phytoplankton use these nutrients for photosynthesis.

16. Some scientists describe the ocean ecosystem more as a web than a chain because many sea creatures eat more than one kind of creature, and some creatures eat others from their own group.

17. OUR OCEAN ECOSYSTEM
Without plankton, all of the oceans animals would die.
All animals in the ocean depend on plankton for survival.