The New Childrens Encyclopedia

75

 SEA ANEMONES
cling to rocks, and
shoot at their prey
with poison barbs.

 SEA SLUGS scrape

algae off hard surfaces

using small sharp teeth

called denticles.

 ANGLER FISH

use the dorsal spine

on their heads like a

fishing rod.

COASTS

Coastlines provide many different

habitats. High up on rocky

shores, tough creatures such as

barnacles survive crashing waves

and exposure at low tide. In

coastal mud, buried bivalves

like clams filter food from

the water.

MAN THE DESTROYER

Modern, intensive fishing boats

can inflict serious harm on ocean

ecosystems. Often, they take too

many of one popular fish or

scoop up endangered species

unintentionally with their catch.

BLACK SMOKERS

At hydrothermal vents, water

heated under the sea dissolves

minerals from the rocks. When it

erupts through the ocean floor,

it forms crusty “chimneys”

that can reach several

yards (meters) in

height.

THE HADAL ZONE extends below the abyssal zone over

less than two percent of the ocean floor. Only two human

beings have ever been there, and we know little about it.

THE ABYSSAL ZONE contains the vast,

muddy, seabed plains (abyssal plains) after

which it’s named, but very little life of any kind.

THE DARK ZONE gets virtually no light, and the

only food is fallout or “snow” from above.Temperatures

are low (35–39°F / 2–4°C), and pressure is high.

THE TWILIGHT ZONE gets just

enough light so that ocean creatures can

hunt, but not enough for photosynthesis.

ZONES AND HABITATS

In fact, the ocean is not just one habitat, but many. The first

few feet (1 m) from the top—the surface layer—is the richest

in both nutrients and vital gases from the atmosphere. But the

surface layer is also vulnerable to pollution and floating litter,

which can damage ocean life. Below this lie five more layers:

 ROCKPOOL ecosystems contain algae and

seaweed. Limpets feed on algae, and starfish

feed on limpets, mussels, and other shellfish.

 FISHING is difficult to

control because no one owns

the open sea, and its vast

waters are hard to police.

OCEAN LAYERS

THE SUNLIT ZONE gets enough sunlight for

photosynthesis to take place. If the water is clear, it

can extend to 650 ft (200 m), but it’s often much

shallower. The base of all food chains is here.

AND ECOLOGYENVIRONMENT

OCEANS AND SEA LIFE

(c) 2012 Dorling Kindersley. All Rights Reserved.(c) 2012 Dorling Kindersley. All Rights Reserved.