Oceanography OverviewOceanography Overview

1. Oceanography: Polar Views of the Earth71% of Earth is covered with oceans

1. Oceanography: Polar Views of the Earth71% of Earth is covered with oceans

Land-Ocean DistributionWhich latitudes have the most land? Which latitudes have the least land?

Land-Ocean DistributionWhich latitudes have the most land? Which latitudes have the least land?

2. Seawater Properties2. Seawater Properties• Salinity

– Measure of dissolved salts in water– Grams dissolved per 1000 grams water– Average salinity is 35 grams of salt per 1000

grams of water

•35%

• Salinity– Measure of dissolved salts in water– Grams dissolved per 1000 grams water– Average salinity is 35 grams of salt per 1000

grams of water

•35% In comparison….(parts per thousand)

• Distilled Water 0

• Lake Erie 2-3

• Ocean35

• Great Salt Lake45

• Dead Sea250

In comparison….(parts per thousand)

• Distilled Water 0

• Lake Erie 2-3

• Ocean35

• Great Salt Lake45

• Dead Sea250

Dissolved elements in Ocean WaterDissolved elements in Ocean WaterChloride and Sodium are the 2 main elements dissolved in ocean water

3. Sunlight penetration3. Sunlight penetration The blue spectrum of sunlight travels the best in water, therefore the oceans look blue.

The top layer of the ocean is warmer due to the penetration of sunlight. The amount of sunlight that penetrates the ocean affects life in the ocean zones.

3. Temperature V/S Depth3. Temperature V/S Depth

Mixed layer

Thermocline

Deep layer

The thermocline is the layer in the ocean where the temperature dramatically decreases. It separates the mixed layer at the top from cold deep layer below.

Remember: Convection currents help transfer heat in our oceans!

4. Ocean currents4. Ocean currents• Ocean currents exist

at many levels in the ocean:

• surface currents, mid-level currents, and deep sea currents.

• Ocean currents help circulate the Sun’s heat and important nutrients for ocean life.

• Ocean currents exist at many levels in the ocean:

• surface currents, mid-level currents, and deep sea currents.

• Ocean currents help circulate the Sun’s heat and important nutrients for ocean life.

5. Upwelling occurs when cold, nutrient rich water rises to replace the warmer, nutrient depleted water.Because cold water is more dense, upwelling is driven by the wind. It pushes the warm water out of the way, so the cold water can rise.

5. Upwelling occurs when cold, nutrient rich water rises to replace the warmer, nutrient depleted water.Because cold water is more dense, upwelling is driven by the wind. It pushes the warm water out of the way, so the cold water can rise.

• Upwelling is important for the fishing industry because it allows nutrients (food) to rise for the fish to eat and grow.

• Upwelling is important for the fishing industry because it allows nutrients (food) to rise for the fish to eat and grow.

El Nino Conditions cause:Loss of fish/fishingWarmer surface waterIncrease in storms (warmer water= more evaporation)

El Nino Conditions cause:Loss of fish/fishingWarmer surface waterIncrease in storms (warmer water= more evaporation)

6. Coral reefs6. Coral reefs• Coral reefs are underwater structures of calcium

carbonate made by corals (living organisms)

• Ancient coral reefs may have formed the present day limestone

• The great barrier reef in Australia is the largest living structure on Earth

• Coral reefs are underwater structures of calcium carbonate made by corals (living organisms)

• Ancient coral reefs may have formed the present day limestone

• The great barrier reef in Australia is the largest living structure on Earth

They are endangered and sensitive. They can be destroyed by temperature changes, pollution, and by being hit/struck.

Formation of a coral atollFormation of a coral atoll• Coral atolls

form from sunken volcanic islands

• They are just one type of coral reef

• The enclosed water is called a lagoon.

• Coral atolls form from sunken volcanic islands

• They are just one type of coral reef

• The enclosed water is called a lagoon.

Most Corals only survive in shallow, warm water 79°-81°F.Coral BleachingBleaching occurs when the corals die. The colors fade away, but the calcium carbonate “shell” remains.