Our OceansEssential Questions: • What have we learned about the oceans over the course of Earth’s history?• How do we find and access information in print and online using the card catalog?

Riddle: How is the ocean like life?

• Draw a vertical line down the middle of your index card. On the left side, list things that you know about the ocean.

• Then on the right side, list things you experienced that involve the ocean.

• Turn the card over and on the back, list things that you learn today.

Our Oceans – Composition and Behavior

There's nothing wrong with enjoying looking at the surface of the ocean itself, except that when you finally see what goes on underwater, you realize that you've been missing the whole point of the ocean. Staying on the surface all the time is like going to the circus and staring at the outside of the tent.”― Dave Barry

Identify the simile – using “like” or “as”What is Dave Barry saying about life in general?

Facts About the Ocean

•The ocean has an average depth of more than ________ feet.•_____ percent of the United States (in terms of our complete legal jurisdiction, which includes ocean territory) lies below the ocean.•We have only explored less than __ percent of the Earth’s oceans. In fact, we have better maps of Mars than we do of the ocean floor (even the submerged half of the United States).

12,40050

5

How Do We Define Oceans?

The oceans are a very large mass of salt water that covers most of the earth. They cover 70% of the globe but we know little about them compared to the land masses. With all the technology that we have, amazingly 95% of Earth’s oceans remains unexplored.

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How Do We Measure the Ocean?

• First, there were few oceanographic tools more sophisticated than a bucket, a thermometer, and a plumb line.

• Beginning around 1939, oceanography rapidly began to be revolutionized with radar, sonar, and electronic navigation devices. Why then?

Why is It Difficult to Explore the Depths of the Ocean?

1. Dive down 650 feet and light starts fading rapidly.

2. At 13,000 feet, the temperature hovers around freezing, and there’s no sunlight at all.

3. People can dive to a depth of 20 meters without gear but the deeper the dive, the higher the pressure on the body.

Underwater Research VehiclesWith the use of these vehicles man has been able to go as deep as a little over 10,000 meters to discover things about the ocean. HOV’s carry scientists themselves to the deep sea to see firsthand what’s there.

The Five Deepest Places on Earth

Mariana Trench, Pacific 35,827 ft

Puerto Rico Trench, Atlantic 30,246 ft

Java Trench, Indian 24,460 ft

Arctic Basin, Arctic 18,456 ft

Southern Ocean, 23,737 ft

Deepest Place on Earth

• Challenger Deep in the Mariana Trench is the deepest point in Earth's oceans. The bottom there is 10,924 meters (35,840 feet) below sea level. If Mount Everest, highest mountain on Earth, were placed at this location it would be covered by over one mile of water.

• The location of the Mariana Trench is 250 miles southwest of the Pacific island of Guam.

• In 2009 researchers from Woods Hole Oceanographic Institution completed the deepest dive by an unmanned robotic vehicle in the Challenger Deep, reaching a depth of 10,902 meters.

How far down in miles is the Challenger Deep?

Deepest Place on

Earth

Then in March , 2012, James Cameron, a Canadian film-director and deep sea explorer, was the first human to descend to a depth of 6.8 miles, by taking a solo journey to the Mariana Trench.

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How many oceans are there?Some ancient civilizations used the phrase “seven seas” to describe the bodies of water known at that time. In medieval times these seas were known as:

Mediterranean SeaIndian OceanBlack SeaCaspian SeaAdriatic SeaPersian GulfRed Sea

Today We Have 5 Oceans

• Atlantic• Pacific• Indian• Arctic• Southern (a newer listing set in 2000, referring

to the ocean around Antarctica)

What We Know About the Ocean Floor

Oceanographers use ocean floor sediments to answer questions about the organisms in them, about the currents that carried them, about climate changes over time, and about the formation of the ocean crust.

The Clues Are in the Sediment

• Different kinds of sediments are found in varying amounts on different parts of the ocean floor. • Some of this sediment is soil and rock particles carried from shore and some is a biogenic ooze consisting of 70 percent mud and 30 percent skeletal debris of microscopic organisms, such as phytoplankton (plants) or zooplankton (animals), the major food source for life in the ocean.

Sea water is 220 times saltier than fresh water.

The ocean is salty because of the gradual concentration of dissolved chemicals and decayed biologic matter eroded from the Earth's crust and washed into the sea.

Ocean currents and winds affect sailing and ocean industries

Current, the movement of the water, is influenced by three things: tides, winds, and differences in density.The water at the ocean surface is moved primarily by winds that blow in certain patterns because of the Earth’s spin.Tides move the water below the surface of the oceans.A third factor that drives currents is thermohaline circulation - a process driven by density differences in water due to temperature (thermo) and salinity (haline) in different parts of the ocean.

“The water of the ocean surface moves in a regular pattern called surface ocean currents. The currents are named. In this map, warm currents are shown in red and cold currents are shown in blue.”

The Ocean’s Currents

What Are Some of the Benefits of Knowing the Currents?

• Traveling along a current saves fuel. Ship routing for safe transport and efficient use of fuel is critical for worldwide commerce.

• Ship routers use environmental information to find routes that minimize transit time, avoid waves over a specific height, or balance travel time and fuel economy against risks to the ship.

• Knowing the currents allow us to predict where chemical drums, spilt oil or other hazardous materials may turn up, and take action to clean up, or protect vulnerable areas.

• Currents are also important for leisure activities such as sailing, scuba diving, sports fishing, and swimming.

Plotting Ocean Currents, Winds, and Depths

Marine navigation charts historically were often produced by a country's Navy and possibly also civil defense bodies and/or port management authorities

In the United States today, NOAA hydrographic survey ships scan the seafloor to identify navigational hazards and obstructions while also acquiring water depth data, in order to create accurate and up-to-date nautical charts.

Look at the top right of the chart to find the major water channel that lies between the coastal land areas of Fort Point and Rocky Neck.

How many feet does the chart say the channel measures? What year was this measurement taken?

Reading a

Nautical Chart

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Reasons Why It is Important to Study the Ocean

• The ocean influences our climate. Most of the oxygen in the atmosphere comes from the ocean.

• The ocean can change our weather patterns.• 25% of the protein used by people comes from

fish.• Oceans affect beach structure• Every process that is taking place on the ocean

floor tells us about the processes that were responsible for the shaping of the earth’s surface.

Coming Soon!

• Oceans: Creatures and Dangers at Sea

• Oceans: Conservation and Our Future

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