The Ocean Floor

Studying the Ocean Floor

• Risky to explore ocean floor

Ways to survey include:• Sonar• SatelliteWays to explore:• Alvin• Deep Flight• Jason II & Medea

Sonar

• Sound Navigation And Ranging

• Sends pulses from a ship down into ocean… bounces off bottom and returns pulse back to ship

• Deeper water = longer pulse response

Satellite

• Seasat – satellite took images that allowed us to measure direction and speed of ocean currents

• Geosat – measures changes in height of ocean’s surface

• Used be top-secret• Now used to make ocean

maps

Regions of Ocean Floor• Ocean floor is not flat• Many features:• Rift valley, mid-ocean

ridge, seamounts, and trenches

• Continental Shelf, C. Slope, C. Rise, and Abyssal Plain

Ocean Floor

Regions of Ocean Floor• Continental shelf – begins at

shoreline and slopes gently toward open ocean. Continues until ocean floor begins to slope more steeply downward Depth can reach 200m

• Continental Slope – begins at edge of continental shelf. Continues down to flattest part of ocean floor. 200m – 4000m

Regions of Ocean Floor• Continental Rise – the base

of the C. Slope, is made of large piles of sediment. The boundary between the continental margin and the deep-ocean basin lies underneath the continental rise.

• Abyssal Plain – the broad, flat part of the deep-ocean basin. It is covered by mud and the remains of tiny marine organisms. The avg depth is 4000m.

Exploring Ocean

• Piloted Vessels:• Alvin: - 7m long- Can reach deepest parts

of ocean- Used to find sunken

ships; lost H bomb- Found life near

hydrothermal vents near Galapagos.

Exploring Ocean• Piloted Vessels:• Deep Flight: - underwater airplane- Goal is to one day dive

11,000m deep.• Robotic Vessels: Jason II

and Medea- Reduce costs w/out pilot- Can withstand high

pressure

Life in the Ocean

Marine Life• Three main groups :- Plankton (microscopic

floaters){Zoo (animal) and Phyto(Plant)}- Nekon (swimming

organisms) – mammals and fish

- Benthos (live at bottom) – crabs, starfish, worms, coral, sponges, seaweed, and clams

Benthic Environment

• Bottom environment• Region near ocean floor

and all the organisms live on or in it

• Zones Include:• Intertidal, Sublittoral,

Baythal, Abyssal, and Hadal

• I’m Sure Being A Handful!

Benthic Environment

Pelagic Environment• Zone near the ocean’s

surface and at middle depths

• Beyond Sublittoral Zone and above Abyssal Zone

• Two Major Zones: Neritic and Oceanic Zone

• Viper Fish Grenadier