A.

D.

C.

B.

Draw and Label the Parts of a Wave

How is the ocean floor studied??

SonarSOund NAvigation and RangingSonar signal sent to ocean floorTime how long it takes to reach bottom and return to

surfaceSide Scan Sonar

Technique that directs sonar waves at an angle

Calculating DepthD = (1500 m/s) (time / 2)1500 m/s = speed of sound in waterExample:If sound signal takes 4 seconds how far away is the

ocean floor at that location?D = (1500 m/s) (4s/2)D = (1500 m/s) (2s)D = 3000 m

SubmersiblesDeep Diving Submersible

2-3 person vesselCan reach moderate to deep depthsExcellent horizontal movement

Self Contained Diving1940s - Developed first

practical scuba (aqua lung)

Released compressed air when diver inhaled

Divers could swim freely rather than walk along bottom

SCUBA= Self Contained Underwater Breathing Apparatus

Ocean FloorContinental Margin

Area where the edges of the continents meet the ocean

Shallowest part of ocean

Includes:Continental ShelfContinental SlopeContinental Rise

Continental ShelfShallowest part of

continental marginExtends into ocean from

shoreAverage width is 60 kmDepth of water – 130 m

Continental SlopeQuick drop in the seafloorTrue edge of continentTurbidity Currents

Fast moving water currents along sea floor that carve out submarine canyons

Continental RiseGently sloping

accumulation of sediment at the bottom of the continental slope

Ocean Floor FeaturesAbyssal Plains

Flattest part of the ocean floor5 to 6 km below surface

SeamountsUnderwater basaltic volcanoes

GuyotsLarge, extinct, volcanoes with flat

submerged tops

Ocean BasinsMid-ocean Ridge

Underwater chain of mountains

Mid-Atlantic RidgeDeep Sea Trenches

Deep Elongated Depressions

Marianas Trench

Hydrothermal VentsAt rift zones, water

seeps through cracks and gets heated.

Hot water rises dissolving minerals out of rocks as it flows

Hydrothermal VentsWater emerges from

seafloor and comes in contact with cold water

Minerals in hot water form a dark cloud called a Black Smoker

Hydrothermal VentsSubmersibles

visited vents more than 2400 meters deep

Temperatures can get as high as 371 Celsius

Case Study1977 – AlvinParts of seafloor

near vents had thick growth of living things

Water very rich in minerals

H2S – Hydrogen Sulfide

AlvinHigh Concentration of

bacteriaBacteria uses H2S to

make foodShare food with other

creaturesChemosynthesis

Vent Life

Giant Clam

Tubeworms

Vent Crab

Pompeii Worm

Life Span of Hydrothermal VentsLife span varies (months to decades)Some vents become inactive if there is no Hydrogen

Sulfide availableEruptions can spill out lava killing organisms at vents

New vents die out and appear regularly