文档介绍：On the bottom
The bottom of the deep ocean is not
an easy place to live. There is little food and
it is dark and cold. Much of the seabed is
covered with soft clays or mudlike oozes
made of skeletons of tiny sea animals and
Underwater cables were laid across the Atlantic
plants. The ooze on the vast open plains of Ocean to relay telegraphic messages, c. 1870
Dried
remains the abyss can reach several hundred yards
of sea thick. Animals walking along the bottom have long legs to keep from stirring
anemones
it up. Some grow anchored to the seabed and have long stems to keep their
feeding structures clear of the ooze. Food particles can be filtered out of the
water, for example, by the feathery arms in sea lilies or through the many pores
in sponges. Some animals, such as sea cucumbers, feed on the seabed and
manage to extract enough goodness from food particles within the ooze. Food
particles are the remains of dead animals (and their droppings) and plants that
have sunk down from above. Occasionally, a larger carcass reaches the bottom
uneaten, providing a real bonanza for the mobile bottom-dwellers that
home in on it from all around. Because food is scarce and temperatures
so low, most animals living in the deep ocean take a long time to grow.
Glassy strands Not a true spider
This sponge grows anchored to the soft seabed by Looking like land spiders, sea spiders belong to a group called ogonids.
its stem of glass strands and sea anemones often Some deep-sea spiders have a leg span of 2 ft (60 cm) across, and can stride
grow on their stems. When a glass-rope sponge along without stirring up clouds of particles. They can also swim, by launching
dies, the cup-shaped part disappears and all that off the seabed, bringing their legs upward, then sinking down again.
is left is the stem stuck
in the seabed.
Stem formed
by long, glassy,
needlelike spikes
made of silica
Long, skinny
le