Outforia Quicktake: Key Takeaways
- Oceans make up 71% of Earth’s surface, but only 5% has been explored.
- Over 80% of the world ocean is not yet mapped or observed.
- Exploration difficulties include cost, technology limitations, high pressure, and cold temperatures in the deep sea.
- Ocean exploration is crucial for understanding global climate change, optimizing ship routes, and researching marine life.
- Notable discoveries include marine life in deep sea, Mariana Trench as the deepest ocean point, and over 6,000 new marine species through the Census of Marine Life.

As curious creatures, humans have managed to explore almost all parts of the Earth’s land. Humans have yet to fully explore the ocean, so how much of the ocean have we explored so far?
Due to the difficulties surrounding ocean exploration, we’ve only explored about 5% of all of our world’s oceans.
To put it into perspective, the oceans make up about 71% of the Earth’s surface. This means that about 95% of the world ocean hasn’t been explored or isn’t fully understood.
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About the Earth’s Ocean

The world ocean makes up about 71% of the Earth’s surface, leaving only 29% of it covered by land.
The oceans around the world provide habitat to more than two million known marine species.
However, the exact number is unknown. It’s estimated that there are still 91% of species in the ocean that have yet to be discovered.
From the ocean’s surface to about 656 ft (200 m) is known as the sunlight zone. Photosynthesizing plants are able to grow in this area because they can receive sunlight. The sunlight zone is easier to explore as it’s easier to see and pressure isn’t as high.
The deep sea or ocean is classified as any point below the 656 ft mark. The next zone below the sunlight zone is known as the twilight zone. This zone has less light, but isn’t completely absent.
If you travel even deeper to around 3,280 ft (1,000), you’ll find yourself in complete darkness.
Since the sun heats the sunlight zone of the ocean, it’s warmer in this zone. However, the deep sea is extremely cold. It has an average temperature of 39°F (4°C).
The pressure is extremely high in the deep sea, which also makes it difficult to explore. Depending on how far you go, the pressure can increase by more than 110 times the pressure we experience in the Earth’s atmosphere.
How Much of the Ocean Have We Explored?

Only 5% of the world ocean has been explored. Some parts that haven’t been explored have been mapped. However, more than 80% of the world ocean has yet to be mapped, explored, or observed.
Such a significant amount of our ocean hasn’t been fully explored for several reasons. Cost and difficulty of ocean exploration are two main factors. Ocean exploration is also fairly new thanks to modern technology.
Although expeditions across the oceans took place centuries ago, these expeditions were mainly for world exploration and travel.
Modern technology has played an important role in exploring our ocean further.
Several significant technologies that contributed to making deep ocean exploration possible only appeared within the last century.
Major technological advancements for ocean exploration have allowed scientists to collect more accurate data about what’s in the deep ocean.
History of Ocean Exploration

The first sailing expeditions occurred in ancient Egypt around 4000 BC. However, these expeditions were believed to occur primarily for traveling purposes across the Mediterranean Sea.
Diving expeditions may have taken place around 1000 BC. Greek poet Homer and Greek philosopher Plato have referenced underwater diving expeditions to collect sponges in their writings.
Ancient civilizations mainly sailed across the seas and participated in underwater diving for travel or warfare.
Around the year 900, vikings went on sea expeditions to conquer the lands of present-day Iceland, Newfoundland, and Greenland.
In 1519, Ferdinand Magellan and his crew successfully completed the first circumnavigation of the world.
A century later, the first submarine was built in 1620 by Dutch engineer Cornelius Drebbel. The submarine was made out of wood and man-powered by oars.
Inventions that could make ocean exploration easier began to appear slowly throughout history.
The first deep ocean sounding to measure the ocean’s depth occurred in 1840 by Sir James Clark Ross in the South Atlantic Ocean. The depth where Ross was located measured at 14,449 ft (4,404 m).
The number of expeditions to explore the depth and composition of the ocean and its sealife increased in the mid-19th century.
Ocean Exploration Discoveries

Several major discoveries have resulted from ocean exploration efforts. The ocean is very environmentally and economically important for humans.
Knowing more about the ocean and what’s in it can help us conserve important marine life and benefit from ocean resources that may be vital to human life. These are some key discoveries that have been made through ocean exploration throughout history.
Marine Life in the Deep Sea

In 1843, naturalist Edward Forbes claimed that life couldn’t exist beyond 1,800 ft (549 m). Known as the Azoic hypothesis, the claim sparked controversy over the existence of marine life for 20 years until it was disproven.
Deep sea life was discovered by Louis F. de Pourtales around 1867 during a dredging operation off the southern coast of Florida. He discovered life as deep as 3,102 ft (945 m).
The Azoic hypothesis was completely dismissed after marine zoologist Charles Wyville Thomson discovered life as deep as 14,400 ft (4,389 m) during a dredging operation.
Deepest Point in the Ocean

The Challenger expedition was one of the first ocean exploration expeditions launched specifically to gather scientific data on the ocean.
The expedition took place between 1872-1876 on the British naval ship HMS Challenger. The expedition was organized to study geological features on the seafloor, marine life, and ocean temperatures and currents.
The Challenger set sail from England and traveled to several parts of the world, including southern Africa, Australia, New Zealand, and the Hawaiian Islands.
As the Challenger traveled through the Pacific Ocean, the crew discovered the deepest point in the ocean.
Using sounding technology, the Mariana Trench was identified as the deepest point in the ocean at almost 7 miles (11.3 km) deep. Throughout the Challenger expedition, the crew also discovered more than 4,500 new marine species.
Census of Marine Life

More than 2,500 scientists from around the world banned together in an international effort to document marine life.
The Census of Marine Life was a 10-year project beginning in 2000 that aimed to better understand marine life.
As a result of the Census programs, scientists discovered more than 6,000 new marine species.
The Census of Marine Life is one of the most extensive reports on ocean life. It led to the discovery of species living in deeper waters than previously thought.
Ocean Exploration Technology

Due to scientific and technological advancements, exploring the ocean has become a little easier over time.
There are several types of technology used to explore the ocean, from underwater vehicles to satellites and geographic information systems (GIS).
Sonar instruments are commonly used to better understand the ocean, its geological features, and objects in it. There are multiple sonar systems or tools that scientists use to study the ocean, such as:
- Multibeam sonar – A sonar system that sends out multiple sound waves to detect objects in the deep sea and map the seafloor.
- Side-scan sonar – An active sonar system capable of detecting objects on the seafloor by using acoustic pulses.
- Split-beam sonar – An active sonar system that emits sound pulses, or pings, to calculate the distance of objects in the ocean from the surface.
Sonars can be used to map the seafloor, discover geological features, and detect objects or marine animals by calculating the distance of the sound waves sent and received from its source.
The first acoustic device used for seafloor exploration was invented by Reignald Fessenden in the early 1900s. The invention led to the creation of sonar systems.
Human-occupied vehicles (HOVs) are another way that scientists can explore the ocean.
Submersibles allow scientists to get a closer look at objects, features, and marine life in the ocean. The first submersible vessel built solely for marine exploration was USS Albatross.

Satellites in space allow scientists and researchers to survey the ocean. The first satellites were launched into space during the space race in the 1950s.
Today, scientists are capable of using satellite data to monitor sea surface temperature, coral reefs, sea ice, and ocean depth.
Several technological advancements initially used for warfare are now used to aid ocean exploration efforts. For example, the first US Navy submarine named the Alligator was built in 1861 to be used in the American Civil War.
In the 1950s, Remotely Operated Vehicles (ROVs) appeared. Interest in ROVs took off when the US Navy began using them to find lost torpedoes.
ROVs became more popular for commercial use in the 1980s. ROVs are now an important part of ocean exploration expeditions that may not be possible in HOVs.
ROVs can vary in size and have a wide range of equipment attached to them to collect various types of data. Many are equipped with cameras, lights, and sonar systems.
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Why is it Difficult to Explore the Ocean?

The most difficult part of ocean exploration is exploring the deep sea. There are several reasons scientists are unable to explore the deepest parts of the ocean.
According to oceanographer Dr. Gene Carl Feldman, certain aspects of exploring the deep sea are more difficult than sending people into space.
Some difficulties that hinder scientists from fully exploring the ocean include:
- Immense amount of pressure in the deep sea
- Cost of expeditions and equipment
- Near freezing temperatures in the deep sea
- Need for further technological advancements
Near freezing temperatures and the intense pressure in the deep sea creates extreme conditions.
In some of the deepest parts of the ocean, the weight of the pressure can be over 1,000 times more than what we experience on the surface.
Although ocean exploration technologies have come a long way, there is still a lot of room for further advancements to make expeditions easier.
Operating ocean research vessels can cost tens of thousands of dollars a day.
More than $1 billion have been allocated to the National Oceanic and Atmospheric Administration (NOAA) for ocean exploration programs.
In June 2021, the Congressional Budget Office summarized the authorization of funds to the NOAA for ocean exploration.
The Ocean Exploration and Research program received $317 million and the Ocean and Coastal Mapping program received $268 million.
The remaining $813 million would be used to fund various programs involving hydrographic surveying.
What is the Deepest Part of the Ocean?
The deepest part of the ocean is called the Mariana Trench. It’s located in the western Pacific Ocean east of the Philippines and southwest of the Northern Mariana Islands and Guam.
The depth of the Mariana Trench was first recorded in 1875 during the Challenger expedition led by the British Royal Navy. A weighted rope attached to the HMS Challenger recorded the depth at 26,850 ft (8,184 m).
A more recent survey conducted by scientists from the University of New Hampshire provided a more accurate measurement of its depth.
The team spent about two months mapping the Mariana Trench in 2010 using a multibeam echo sounder.
They measured the deepest point in the Mariana Trench, named the Challenger Deep, at 36,070 ft (10,994 m). That equals almost 7 miles (11 km)!
The average depth of the entire ocean is about 2.3 miles (3.7 km).
Why is Ocean Exploration Important?

Studying the ocean is important for many reasons. Understanding the ocean can aid in scientific research, conservation and preservation, and the exploitation of resources.
Some of the major benefits of exploring the ocean include:
- Understanding global climate change
- Forecasting certain weather events
- Optimization of ship routes
- Research and management of marine life
Understanding our ocean better also has social and economic benefits. It can help aid in the discovery of new medicinal drugs to fight and cure diseases. It can help us better preserve and manage resources that contribute to food and energy needs.
There are a few priorities that ocean exploration efforts focus on, such as:
- Management of vital deep sea coral reefs and marine life habitats
- Understanding how marine resources can help make the use of natural resources more sustainable
- Forecasting of natural disasters and seafloor hazards
The ocean is essential to all life on Earth. It regulates the Earth’s temperature and produces about half of the Earth’s oxygen.
Many businesses also depend on oceans to produce various goods and services, including food and recreation.
The ocean economy supported about 3.3 million jobs and contributed about $307 billion to the US gross domestic product (GDP) in 2017.
Without the ocean, life on Earth would cease to exist. Major threats to the ocean’s viability have the potential to alter the Earth’s processes. Main threats to the ocean include pollution, climate change, and overfishing.
Plastic pollution in the ocean has really taken a toll on marine life. Sea animals, such as sea turtles, can easily become entangled or ingest plastics. It can injure sea animals, make them sick, or cause them to die.
Sea levels are rising and the ocean temperature is warming as a result of climate change. Exploring the ocean provides better insight to how human mismanagement is affecting the ocean.
Future Ocean Exploration Plans

The NOAA has several ocean exploration programs currently in place for the 2023 year. Some of these programs include:
- 2023 Seascape Alaska Expeditions – Operating between May-September 2023 to better understand unexplored and poorly understood deep sea waters off the coast of Alaska.
- Exploration Vessel Nautilus – Operating between April-December 2023 to map the central and eastern Pacific and explore deep sea habitats.
- Express West Coast Exploration – Launched in October 2022 to better understand poorly known and explored areas of the deep sea off the US West Coast.
- Deep-Sea Pacific Ocean Biodiversity – A two year program launched in May 2022 to use environmental DNA to explore and study deep sea coral communities.
An international program called Seabed 2030 was launched in 2017 with the goal of mapping the entire ocean floor by 2030.
This extensive project may provide us with a deeper understanding of the ocean floor and lead to major discoveries in the process.
It may provide scientists with more data to understand sustainable fisheries management, ocean acidification, and climate change.
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Fun Facts

The Pacific Ocean houses the largest living structure on Earth.
The largest living structure on Earth is the Great Barrier Reef. It contains the largest number of coral reef communities in the entire world. It’s home to at least 1,500 fish species and 400 types of coral.
The Great Barrier Reef covers about 133,000 square miles (344,468 sq km) and can be seen from outer space!
Millions of tons of plastic end up in the ocean each year.
According to the International Union of Conservation of Nature (IUCN), out of the 300 million tons of plastic produced each year, at least 14 million tons of it ends up in the ocean. Plastic is the most abundant type of marine debris.
Plastics end up in the ocean in several ways, including illegal dumping, littering, mismanagement of waste disposal, and runoff.
Most of the Earth’s volcanic activity occurs in the ocean.
More than half of the active volcanoes on Earth are located along the tectonic plate boundaries. There’s one spot in the world called the Ring of Fire that sees the most volcanic and seismic activity.
The Ring of Fire surrounds the Pacific Ocean. It’s about 25,000 miles (40,250 km) long and outlines where tectonic plates meet the Pacific Plate.
How much of the ocean have we explored FAQ

Who explores the ocean?
Ocean exploration involves a large crew of researchers and scientists.
There are several types of scientists involved in ocean exploration expeditions. Some examples include oceanographers, marine biologists, geologists, surveyors, geophysicists, and ocean engineers.
What will the ocean be like in 2050?
The rising of sea levels is one of the major changes to the ocean expected by 2050.
According to the NOAA, sea levels are projected to rise about 10-12 inches (25-30 cm) over the next few decades.
Although this doesn’t sound like much, it’s pretty significant. It can put some coastal cities entirely underwater depending on land height. Remaining coastal cities will see an increase in coastal flooding.
Some studies suggest that by 2050, there will be more plastics in the ocean than fish.
What is happening to the ocean in 2023?
A major resolution to protect the ocean from plastic pollution was introduced in 2022.
The United Nations Environment Assembly adopted an international binding agreement to address the increase of plastic pollution in the ocean.
International efforts to map, manage, and protect the ocean have become more common. Cooperation between nations can make ocean exploration and protection efforts easier.
As of 2023, the ocean is warming, sea levels are rising, and coral reefs are experiencing stress due to warmer temperatures.
Can the ocean still be saved?
Scientists claim that the ocean can be saved, but several changes need to occur for that to happen.
A collective effort amongst all humans is needed to conserve and protect the ocean.
Human activities that negatively impact the environment have short and long-term effects. Some of the consequences that we’re seeing now are the result of human activities that have taken place over decades.
If mismanagement continues and restoration efforts aren’t taken seriously, some of these negative impacts may become irreversible by 2050.