Page 179 - (DK) Ocean - The Definitive Visual Guide

THE CONTINENTAL SLOPE AND RISE 177

submarine canyon some sediments
past shoreline extends from shelf deposited as delta
formed by to abyssal plain at river mouth
higher sea
level in past material from
uplands is
gradually
sediments
present carried down eroded and
shoreline washed into
river to sea
rivers

GANGES DELTA
The Ganges River
carries 2 billion tons
of sediment a year.
Some is deposited in this
massive delta. More is
carried out to sea where
it forms a deep-sea fan
over the Bay of Bengal.

TUBE ANEMONES
These sea anemones bury
their bodies in sediment, at
depths of 13,100 ft (4,000 m),
feeding with their tentacles.

DISCOVERY
COASTAL PLAIN MOUNTAINS
SHORELINE
Shorelines are An area of low-lying, These rocks formed on STAKING A CLAIM
shaped by erosion flat land between the an ancient sea bed and
and deposition and uplands and the sea. were later uplifted.
move with changing Erosion will eventually Lured by vast oil reserves, oil
sea levels. return them to the sea. companies have begun drilling in
waters as deep as 7,550 ft (2,300 m)
on the continental slope. These
SEDIMENT FEEDER waters are also increasingly important
CONTINENTAL RISE CONTINENTAL CONTINENTAL SHELF
Deeper sediments SLOPE The continental shelf is Brittlestars are among the for fisheries, so coastal countries
build up, creating a The slope drops to typically 460–660 ft most common animals found want to establish national waters
gentle gradient of less 9,800 ft (3,000 m) (140–200 m) below the where they have sole rights to
than 1 in 100. at a gradient of surface. Its width feeding on the sediment
1 in 50. varies greatly. of the continental rise. these resources. Under current
maritime law, the rights of a
central disk coastal state over certain resources,
Continental Rise such as oil, extend out to the
continental margin —essentially to
The continental rise is a thick wedge of sediment, up to the boundary between continental
9 miles (15 km) deep, formed from material that has slumped rise and abyssal plain—or to 200
downward to the base of the continental slope. This wedge nautical miles from the coast,
drops gently away toward the abyssal plain. These sediment whichever is the greater (but never
mounds are particularly extensive where several deep-sea exceeding 350 nautical miles).
fans meet and coalesce at the foot of submarine canyons. The
mouth (on
geological boundary between the continental and oceanic underside of disk)
crusts is completely obscured beneath these sediments.
The sediments of the continental rise merge five arms,
arranged radially
into the abyssal plains beyond. Brittlestars and
polychaete worms, a type of segmented
worm, live on the sediments, surviving
on detritus falling from above. Atlantic
red crabs scavenge on the seabed, OCEAN ENVIRONMENTS
migrating up the continental slope to LIZARDFISH HABITAT
breed. Deep-sea cod, Dover sole, The highfin lizardfish
rockfish, goosefish, and thornyheads are is found on the abyssal
among the demersal species living on plain and continental
rise, typically below
the slope and rise. Trawling has damaged
about 6,600 ft (2,000 m),
many of these habitats, but the deeper in water colder than
canyons remain havens of biodiversity. 39ºF (4ºC).