Figure 25 The marine biome
is divided into several zones.
A. Tidepools are common in the
intertidal zone. This zone lies
between the highest high-tide line
and lowest low-tide line. B. Many
fish, such as these silvery mackerel,
inhabit the shallow waters over the
continental shelf, called the neritic
zone. C. A humpback whale feeds
on algae at the surface of the openocean zone. D. This eerie deep-sea
gulper is a predator in the deepest
part of the ocean.
These organisms provide food and shelter for a variety of animals,
including crabs, worms, clams, oysters, and fish. Many of these
organisms use the calm waters of estuaries for breeding grounds.
Intertidal Zone Next, you take a walk along the rocky shore-
line. The part of the shore between the highest high-tide line and
the lowest low-tide line is called the intertidal zone. Organisms
here must be able to withstand the pomiding action of waves,
sudden changes in temperature, and being both coveted with
water and then exposed to the air. It is a difficult place to five!You
observe many animals, such as barnacles and sea stairs,clinging to
the rocks. Others, such as clams and crabs, burrow in the sand.
Neritic Zone Now it's time to set out to sea to explore the
waters near shore. From your research vessel, your group will
explore the next type of marine habitat. The edge of a continent
extends into the ocean for a short distance, like a shelf. Below the
low-tide line is a region of shallow water, called the neritic zone
(nuh RIT ik), that extends over the continental shelf. Just as in
freshwater biomes, the shallow water in tbis zone allows photosynthesis to occur. As a result, this zone is particularly rich in living
things. Many large schools of fish such as sardines and anchovies
feed on the algae in the neritic zone. In the warm ocean waters of
the tropics, coral reefs may form in the neritic zone. Though a
coral reef may look like stone, it is actually a living home to a wide
variety of other organisms.
Surface Zone Out in the open ocean, light penetrates through
the water only to a depth of a few hundred meters. Algae floating in these surface waters carry out photosynthesis. These algae
72. E
are the producers that form the base of almost all open-ocean
food webs. Other marine animals, such as tuna, swordfish, and
whales, depend directly or indirectly on the algae for food.
Deep Zone The deep zone is located in the open ocean below
the surface zone. Throughout most of the deep ocean, the water
is completely dark. Your expedition will need to use a submarine
with bright headlights to explore this region. How can anything
live in a place with no sunlight? Most animals in this zone feed
on remains of organisms that sink down from the surface zone.
The deepest parts of the deep zone are home to bizarre-looking
animals, such as giant squid that glow in the dark and fish with
rows and rows of sharp teeth.
After you have recorded your deep-zone observations, your
long expedition is over at last. You can finally return home.
Review
1. How does climate determine a biome's characteristics?
2. Where in water biomes can photosynthesis occur?
3. Which land biome receives the most precipitation?
Which two receive the least?
4. In which biome would you find large herbivores such
as antelope and elephants? Explain your answer.
5. Thinking Critically Comparing and
Contrasting How are the three forest biomes
(rain forests, deciduous forests, and boreal forests)
alike? How are they different?
................................
~=~rll~
..·
Check Your Progress
"2
By now you should be
ready to start analyzing the data
you have collected about your
compost chambers. Do your
observations of the two
chambers support your
hypothesis? Begin to prepare
your report.
Chapter 2
E. 73