Transcript ocean floor and life

The Seafloor
The ocean floor is not flat.
It has all the features and landforms that are found on dry land.
**Copy the diagram of the seafloor from the board.**
The continental shelf and slope are the edge of the continent.
Rift zone - where ocean floor is spreading; hot lava oozes
out through cracks; solidifies and becomes new land
Mid-ocean ridges - mountain chains alongside rift zones;
many volcanoes
Trenches - formed when one piece of the seafloor is pushed
beneath another; forms a deep canyon
Ex. Marianas Trench = 11 km deep, Grand Canyon = 1.6 km
Island - top of underwater mountain that reaches the surface
Abyssal plain - flat area
Seamount - underwater mountain
Waves cause the shoreline to constantly change.
Sandy beaches are eroded more rapidly than rocky shores.
Life in the Ocean
Living in the ocean can actually be easier than living on land.
1.) Organisms in the ocean use less energy for movement due
to buoyancy.
2.) Temperature changes are less drastic than on land.
3.) There is never a lack of water.
4.) Waste disposal is easy and cleaner.
5.) External fertilization is carried out very easily.
Many ocean plants carry out photosynthesis, but other
organisms carry out chemosynthesis.
This means they use chemicals other than oxygen to make their
own food.
For example, bacteria near deep sea vents use sulfur to make their
energy.
Ocean organisms fall into one of three main categories
based on their movement.
Plankton - mostly microscopic; “drifters”; can’t move on
their own, so they are carried by the currents; at top of ocean
Ex. - diatoms; algae; krill
Nekton - larger animals; able to swim; can move to all different
levels
Ex. Fish, whales
Benthos - bottom dwellers; do not leave the bottom; usually poor
swimmers; may even live attached to the bottom
Ex. Sea anemones, starfish, crabs, clams