Part 1 Chap 14.1 Oceans

Chapter 14.1 : 

Chapter 14.1 The vast world ocean

Oceans : 

Oceans Despite our planet being called Earth, most of the surface of the planet is water Nearly 71% of Earth’s surface is covered by the global ocean

Oceans : 

Oceans

Oceans : 

Oceans Geography of the oceans The world ocean can be divided into four main ocean basins The Pacific Ocean The Atlantic Ocean The Indian Ocean The Arctic Ocean

Oceans : 

Oceans Pacific Ocean Largest Covers more than half the ocean surface on Earth Deepest Average depth is 3940 m (2.4 miles) Bounded on east and west by continents

Oceans : 

Oceans Atlantic Ocean Half the size of the Pacific Not quite as deep as Pacific Bounded on east and west by continents

Oceans : 

Oceans Indian Ocean Smaller than Atlantic Same average depth as Atlantic Almost entirely in the southern hemisphere

Oceans : 

Oceans Arctic Ocean Smallest 1/7th size of Pacific Shallowest 1/4th as deep as the rest of the oceans Entirely in the northern hemisphere

Oceans : 

Oceans Not until the late 1800s did the ocean became an important focus of study New technologies have allowed us to learn more the ocean The field of science that studies oceans is called oceanography Oceanography draws on knowledge of geology, chemistry, physics, and biology to help explain all aspects of the world ocean

Oceans : 

Oceans Mapping the ocean floor The topography of the ocean floor is as diverse as that of continents The ocean floor has Mountains Valleys Trenches Plains Vents Volcanoes Sea mounts Cliffs

Oceans : 

Oceans In some places on the sea floor, even lakes can be found These are at the bottom of the Gulf of Mexico and are extremely briny

Oceans : 

Oceans Mapping the ocean floor Bathymetry is the measurement of the depths and charting of the shape or topography of the ocean floor The HMS Challenger (Dec 1874 –May 1876) expedition made the first study of the global ocean ever attempted by one agency. During the three and a half year voyage it covered every ocean except the Arctic Ocean

Oceans : 

Oceans Mapping the ocean floor Today modern technology has replaced older technology such as lowering long, weighted lines overboard to measure depth Mapping today is accomplished using tools such as Sonar Satellites Submersibles

Oceans : 

Oceans Mapping the ocean floor Sonar A type of electronic depth-sounding equipment Sonar stands for Sound Navigation And Ranging It uses sound echoes and time of travel for the echoes to find distance

Oceans : 

Oceans Mapping the ocean floor Two main types of sonar are used Sonar Multibeam sonar

Oceans : 

Oceans Mapping the Ocean floor Sonar Many sonar readings are taken Each reading tells the depth at a specific point All the readings are compiled together to obtain a profile of the ocean floor in that area

Oceans : 

Oceans Mapping the Ocean floor Multibeam Sonar Uses more than one sound source and listening device Obtains profiles of narrow strips of area instead of single points The ship travels at a steady pace back and forth

Oceans : 

Oceans Mapping the Ocean floor Satellites The ocean surface is not flat! Where the ocean surface is higher, large features are found on the sea floor Where the ocean surface is lower, canyons and trenches are found This is caused by gravity Gravity attracts water toward regions where massive ocean floor features occur So, more water gathers in places where there are large features causing the ocean surface to rise

Oceans : 

Oceans Mapping the Ocean floor Satellites Use microwaves Devices on the satellite can measure variations in surface height as small as 3 to 6 centimeters

Oceans : 

Oceans Mapping the Ocean floor Submersibles A submersible is a small underwater craft used for deep-sea research They collect data about areas of ocean previously unreachable by humans They collect data such as: Temperature, pressure, videos, photographs, water samples, and sediment samples

Oceans : 

Oceans Mapping the Ocean floor Submersibles The first one was used in 1934 and went to a depth of 923 meters By 1960 the technology reached the point that Jacques Piccard was able to go in an untethered submersible 10,912 meters into the Mariana Trench Many submersibles used today are unmanned and can stay under for days, weeks, or longer