Into the Abyss
The ocean is deep (check out the facts)
- Area: about 140 million square miles (362 million sq km), ore nearly 71% of the Earth's surface.
- Average Depth: 12,200 feet (3,720 m).Deepest point: 36,198 feet (11,033 m) in the Mariana Trench in the western Pacific.
- Mountains: The ocean ridges form a great mountain range, almost 40,000 miles (64,000 km) long, that weaves its way through all the major oceans. It is the largest single feature on Earth.
- Highest Mountain: Mauna Kea, Hawaii, rises 33,474 feet (10,203 m) from its base on the ocean floor; only 13,680 feet (4,170 m) are above sea level.
- Click here to see more facts about the ocean
The Five Layers of the Deep Sea
Epipelagic (sunlight zone)
Mesopelagic (twilight zone)
Bathypelagic (midnight zone)
Abyssopelagic (abyssal zone)
Hadalpelagic (the trenches)
Most of the Ocean is Dark and Cold
In the clearest parts of the ocean light can penetrate to almost 1,000 meters (in most places its far less). Over 90% of the ocean's volume is below this. Due to the difficulties in exploring such habitat (dark, cold, and under extreme pressure) we know very little about the organisms that live there. To learn more check out: The Deep Sea Physical Characteristics
Adapting to Life in the Darkness
 Life in the deep sea survives only because it has adapted over the millennium to some truly extreme conditions. Life in the deep sea is cold (on average four degrees Celsius,) completely dark, under bone crushing pressure, and nearly devoid of hard surfaces or anything interesting to touch or feel. The life that has resulted is normally very small, but often grotesque in its appearances. To check out some of these life forms use the links below.
NOAA - Deep Sea Gallery
Monterey Bay Aquarium -Missions to the Deep
Mesopelagic and Deep Sea Fishes
Exploring the Deep Sea
On January 23, 1960, the crew of the Trieste reached the bottom of the Challenger Deep in the Pacific Ocean's Mariana Trench and set a deep diving record -- 35,810 feet -- that will likely never be bested. No one has even tried. In fact, in the nearly 40 years since, no person has plunged to within 10,000 feet of the record. In 1995, a ROV (Remotely Operated Vehicle) from Japan called Kaiko reached Challenger Deep, but was unfortunately lost at sea in 2003. Click on the link to read about this amazing robot.
Although none went as deep, there have been many other important deep sea submersibles besides the Trieste. To learn more click on deep sea machines.
The highest pressure found in the ocean is located in Challenger Deep (part of the Mariana Trench) in the western Pacific. It is almost 36,000 ft or 11,000 m deep. That much water overhead creates the most intense pressures that can be found on earth with almost 1100 atm of pressure.
For depth limits of submersibles and some deep sea fish too, go to the Smithsonian's How Deep Can They Go page.
An even easier way to explore the deep sea is to attach a camera to marine organism naturally designed to handle depth much better than we do. Researches have attached so called "Critter Cam's" to sperm whales and penguins both to study the animals themselves as well as make observations of other deep sea life. Click on link to take a virtual tour of the deep sea through the "eyes" of a sperm whale.
 Thermal Vent Communities
In 1977, scientists diving off of the Galapagos Islands made one of the most amazing discoveries in Oceanography in the last century. There are places in the bottom of the ocean that defy all of the rules of deep sea life. Deep sea hydrothermal (hot water) vents and cold methane seeps are rich with life. Scientists discovered species so bizarre whole new phylum's had to be created to categorize them. Most of these communities were dominated by giant tube worms that had neither mouths, nor guts, nor anus. Bacteria (that live near these vents and in other organism near these vents) convert chemicals (from the sulfur-rich fluid spewed out of vents) to energy, in a process called chemosynthesis. Click here to learn more about the organisms that live in these extreme deep sea communities.
Hydrothermal vents - These are deep volcanic hot springs, mainly along the mid ocean ridges. They can have temperatures that exceed 400 degrees C. The water that comes out of them is mineral-laden and provides abundant energy to the organisms that live around it. Click here to learn more about the geology of hydrothermal vents.
Cold hydrocarbon seeps - These are mostly along continental margins, where gases (methane and hydrogen sulfide) and oil seep out of the sediments and also provide abundant energy.
Questions to Research
As always, your textbook may be of great assistance to you. For this unit, try chapter 16.
- The Deep Sea Physical Characteristics Describe three difficult physical conditions that life has to adapt to in order to survive in the deep ocean.
- Examine the image showing oceanic layers. Based on what you see and read, create a chart showing physical features for the epipelagic, meso/ bathypelagic, abyssal pelagic and hadal pelagic.
- Provide and example of a mesopelagic, abyssal pelagic, and hadal fish species.
- Go to the Blue Planet - Deep Sea Page, click on "dive to the abyss." Read the objectives carefully. This game takes 10 minutes, and you want to succeed just once. Show your teacher when you finish, and they will initial the question for you.
- Go to the Blue Planet - Deep Sea Page, click on "under pressure." Play the interactive game and keep track of all of the "real species" and the facts you learn about each one.
- Based on the section how deep they can go link, create a chart showing the names, dive time, and depth ratings of four submersibles.
- Describe what a tube worm is and how it gets its nutrition. Also describe two other unusual species can be found in deep sea hydrothermal vents. Click here to learn about some of the other organisms that live in these vents.
- Describe some of the mysteries about deep sea vents that scientists are still trying to solve.
- Color in your deep sea coloring handout.
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