ECOSYSTEMS OF THE OCEAN SOL 5.6 Biological Characteristics

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

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.

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.

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

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

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

The ocean is full of organisms and marine life.

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

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

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

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

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

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.

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.

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