1. Chapter 19
Oceanography

2. Section 1 – The Seafloor
Ocean basins – low areas of Earth filled with water
Continental shelf – gradually sloping end of the continent that extends under the ocean
Continental slope – steeper slope that extends from the outer edge of the continental shelf down to the ocean floor
Abyssal plains – flat seafloor areas from 4,000 m to 6,000 m below the ocean surface

3. Section 1 – The Seafloor… Continued
As crustal plates move, the ocean floor changes
Mid-ocean ridge – new ocean floor is formed.
Eruption of magma from Earth’s interior
Process called seafloor spreading
Trenches – long, narrow, steep-sided depressions
Form at subduction zones where one crustal plate sinks beneath another
Example: Mariana Trench

4. Section 1 – The Seafloor… Continued
Many mineral resources can be found in the ocean.
Petroleum, natural gas, phosphorite, limestone, sand gravel – examples of continental shelf deposits
Economically important - can be mined
Placer deposits – can form where rivers enter oceans
Sulfur, iron, copper, zinc, silver –examples of deep-water deposits
Too difficult and expensive to mine
Manganese nodules – deposits that form from seawater

5. Section 2 – Life in the Ocean
Ocean organisms carry out life processes every day.
Photosynthesis – marine plants and algae use energy from the Sun to make food.
Producers – organisms that undergo photosynthesis
Consumers – organisms that feed on producers
Chemosynthesis – the process of using sulfur or nitrogen compounds as energy to produce food
Energy is passed from one organism to another organism in a food chain
Complex feeding system of overlapping food chains – food webs

6. Section 2 – Life in the Ocean… Continued
Varieties of ocean life
Plankton – marine organisms that drift with the current
Phytoplankton – producers
Zooplankton – feed on phytoplankton
Nekton – animals that actively swim rather than drift in the current
Can control their buoyancy
Some deep-dwelling nekton produce their own light
Benthos – plants and animals living on or in the seafloor

7. Section 2 – Life in the Ocean… Continued
Habitats along the near-shore areas of the continental shelf – ocean margin habitats
Beach – dwelling organisms are adapted to a constantly changing environment.
Tide pools formed in rocky shore areas contain food and provide protection.
Estuaries provide a lower salt environment with many nutrients.
A coral reef forms in clear, warm water an provides a habitat for many species

8. Section 3 – Ocean Pollution
Pollution – introduction of harmful waste products, chemicals, and other substances not native to an environment
Sewage – pollutant that acts like a fertilizer
Creates algal blooms
Uses up oxygen so other organisms die
Chemicals – wastes from industrial and agricultural products
Oil – from tankers and land runoff

9. Section 3 – Ocean Pollution… Continued
Solid wastes – debris washed up on beaches that kill or create hazards for animals
Silt – sediment from erosion that can cover coral reefs or fill marshes
Pollution effects – ocean environments are drastically changing
Pollution control – international organizations and treaties work to reduce ocean pollution.

10. Section 3 – Ocean Pollution… Continued
No international agreement exists to control land based activities that affect the oceans.
Everyone’s cooperation is needed
Continue to learn about marine pollution