Earth Science
Chapter 14
Section 3
A. Conditions of the Neritic Zone:
Horizontal zone of the ocean.
Intertidal Zone- stretches from the highest high-tide line on
the land out to the point on the continental shelf exposed by
the lowest low tide.
Neritic Zone- the part of the ocean that extends from the
low-tide line out to the edge of the continental shelf.
Open-Ocean Zone- beyond the edge of the continental shelf.
The shallow water over the continental shelf receives
sunlight and a steady supply of nutrients washed from the
land into the ocean.
The light and nutrients enable large plantlike algae, such as
the giant kelp to grow.
These algae serve as a food source and shelter for other
organisms.
In parts of the neritic zone, nutrients from upwelling supports
plankton, which increases fish population - good for fishing
and the ocean food web.
Two diverse habitats typically found in the neritic zone.
1. Kelp forests
2. Coral reefs
Kelp Forests
Grow in neritic waters
They are large and heavy algae
They require a solid rocky bottom to anchor their stalks
A bundle of root-like strands called a holdfast attach the
algae to the rocks.
A stalk of Giant Kelp can grow to 30 meters in length.
Kelp produce food through photosynthesis.
Provide a habitat for many organisms.
Sea urchins can wipe out a kelp forest if not kept under
control by sea otters that eat them.
Once thriving kelp forests can become a barren rocky zone.
Coral reefs
Coral reefs are found in warm, shallow waters.
They are formed by groups of tiny coral animals that produce
a hard material around their soft bodies.
When the animals die the hard material is left behind.
Over time the hard remains create a coral reef.
Organism like the octopuses, spiny lobsters, shrimp, moray
eels and colorful fish live among the reefs.
B. Conditions in the Open Ocean:
Two Zones are identified in the open ocean.
1. Surface Zone
2. Deep Zone
The surface zone is the only part of the open ocean that
receives enough sunlight to support the growth of algae.
These microscopic algae are the base for the open ocean food
web.
In the deep zone, there is no sunlight. Finding food in the
deep zone darkness is a challenge. Many deep sea fishes
produce their own light.
The production of light by living things is called
bioluminescence.
Some organisms use chemical reactions to produce light,
others have light-producing organs and some have
bioluminescent bacteria living in their bodies.
C. Hydrothermal Vents:
A hydrothermal vent is an area where ocean water sinks through
cracks in the ocean floor, is heated by magma and rises again
through cracks.
These vents are located along ocean ridges where new ocean
floor is being created.
The heated water coming from a vent carries gases and minerals
from Earth’s interior.
The chemical nutrients in the heated water support the unique
group of organisms that are found around hydrothermal vents.