Arctic Ocean facts for kids

Kids Encyclopedia Facts

"Arctic Sea" redirects here. For the cargo ship, see MV Arctic Sea.

The Arctic Ocean, showing its borders as defined by the International Hydrographic Organization.

Earth's ocean, showing common divisions

Earth's thermohaline circulation seawater flow

Map with five-oceans (approximate boundaries)

Earth's ocean

Main five oceans division:

Further subdivision:

Marginal seas

The Arctic Ocean is the smallest and shallowest of the world's five oceans. It covers an area of about 14 million square kilometers. This ocean is the coldest on Earth. Some experts call it the Arctic Mediterranean Sea or North Polar Sea. It is also seen as the northernmost part of the entire world ocean.

The Arctic Ocean is located around the North Pole in the middle of the Northern Hemisphere. It stretches south to about 60°N latitude. The continents of Eurasia and North America surround it. Its borders are defined by natural features like the Bering Strait on the Pacific side. On the Atlantic side, it's bordered by the Greenland Scotland Ridge. Most of the Arctic Ocean is covered by sea ice all year. In winter, it is almost completely frozen.

The temperature and saltiness of the Arctic Ocean's surface change with the seasons. This happens as the ice melts and freezes. Its water is the least salty of all major oceans. This is because there is little evaporation and a lot of fresh water flows in from rivers. Also, it has limited connections to saltier ocean waters nearby. The amount of ice cover shrinks by about 50% in summer. Satellite data shows a continuous decrease in Arctic sea ice. In September 2012, the ice reached a new record low.

History of the Arctic Ocean

Early People in North America

People have lived in the North American Arctic for a very long time. This goes back at least 17,000 to 50,000 years ago. During the Ice Age, lower sea levels allowed people to cross a land bridge. This bridge connected Siberia to what is now Alaska. This led to the first settlements in the Americas.

An ancient Thule settlement site.

Early groups included the Pre-Dorset people (around 3200–850 BC). The Saqqaq culture lived in Greenland (2500–800 BC). The Independence I and II cultures were in northeastern Canada and Greenland. The Groswater people lived in Labrador and Nunavik. The Dorset culture spread across the Arctic between 500 BC and AD 1500. They were the last major Paleo-Eskimo group. After them came the Thule people, who are the ancestors of today's Inuit.

The Thule culture lasted from about 200 BC to AD 1600. They started near the Bering Strait and spread across most of Arctic North America. Today, Inuit people live in Alaska, Northwest Territories, Nunavut, Nunavik, Labrador, and Greenland.

European Exploration

For a long time, Europeans knew little about the North Pole region. Its geography was mostly guesswork. Around 325 BC, a Greek explorer named Pytheas traveled north. He described a land called "Eschate Thule." There, the sun only set for three hours a day. He said the water was a frozen substance. He was likely describing loose sea ice. His "Thule" was probably Norway.

An 18th-century map of the Arctic, showing a "Northern Ocean."

Early mapmakers were unsure how to draw the North Pole. Some maps showed land, while others showed only water. Few expeditions went far beyond the Arctic Circle back then. They only discovered small islands like Novaya Zemlya (in the 11th century) and Spitzbergen (in 1596). From the late 1500s to the early 1900s, more expeditions explored the Arctic Ocean. Many were looking for trade routes from Europe to the Pacific Ocean. This helped improve our knowledge of the region's geography.

A map of the Arctic region, showing important shipping routes like the Northeast Passage and Northwest Passage.

Arctic Exploration in the 1800s

People didn't know what lay north of the ice. This led to many ideas, like the myth of an "Open Polar Sea." This was a belief that a warm, ice-free sea existed at the North Pole. Sir John Barrow, a British official, encouraged exploration from 1818 to 1845. He hoped to find this sea.

In the United States, explorers Elisha Kane and Isaac Israel Hayes claimed to have seen parts of this sea. Even a famous expert, Matthew Fontaine Maury, wrote about it in 1883. However, explorers who got closer to the pole found thick, year-round ice. By the early 1900s, the idea of an Open Polar Sea was proven wrong.

Fridtjof Nansen was the first to sail across the Arctic Ocean. He did this during the Fram Expedition from 1893 to 1896.

Arctic Exploration in the 1900s

The first surface crossing of the ocean happened in 1969. Wally Herbert led a dog sled expedition from Alaska to Svalbard. The submarine USS Nautilus made the first underwater trip across the North Pole in 1958. In 1977, the icebreaker NS Arktika made the first surface trip across the North Pole.

Since 1937, Russian scientists have used manned drifting ice stations. These stations were set up on ice floes. They drifted thousands of kilometers while scientists studied the ocean.

During World War II, the European part of the Arctic Ocean was very important. Allies sent supplies to the Soviet Union through northern ports. German naval and air forces tried to stop these convoys.

In 1954, Scandinavian Airlines (SAS) started the first commercial flights over the Arctic Ocean. These flights connected Los Angeles and Copenhagen.

Arctic in the 2000s

In recent times, there have been discussions about the importance of Arctic territories and their resources. For example, in 2019, there was a proposal regarding Greenland. Leaders have also discussed the control of resources and waterways in the Arctic, like the Northwest Passage, due to their economic and strategic value.

Geography of the Arctic Ocean

A map showing the depths of the Arctic Ocean and the surrounding land.

The Arctic region, with its southern border marked by a line where the average July temperature is less than 10°C.

Size and Shape

The Arctic Ocean has a roughly circular shape. It covers about 14 million square kilometers. This is almost the size of Antarctica. Its coastline is about 45,390 kilometers long. It is the only ocean smaller than Russia.

Surrounding Lands and Economic Zones

The Arctic Ocean is surrounded by several landmasses. These include Eurasia (Russia and Norway), North America (Canada and Alaska in the U.S.), Greenland, and Iceland. Many countries have special economic zones in the Arctic. These zones give them rights to explore and use marine resources.

Subareas and Connections

The Arctic Ocean connects to the Pacific Ocean through the Bering Strait. It connects to the Atlantic Ocean through the Greenland Sea and Labrador Sea.

The largest seas within the Arctic Ocean include:

Islands of the Arctic

Many islands and groups of islands are found in the Arctic Ocean. Some of the main ones are:

Jan Mayen (Norway)
Iceland
Greenland
Arctic Archipelago (Canada)
Wrangel Island (Russia)
New Siberian Islands (Russia)
Severnaya Zemlya (Russia)
Novaya Zemlya (Russia)
Franz Josef Land (Russia)
Svalbard (Norway)

Ports and Harbors

There are several important ports and harbors along the Arctic Ocean. These include:

In Alaska: Utqiaġvik (Barrow) and Prudhoe Bay.
In Canada: Churchill (Manitoba), Nanisivik (Nunavut), Tuktoyaktuk, and Inuvik (Northwest Territories).
In Greenland: Nuuk.
In Norway: Kirkenes, Vardø, and Longyearbyen (Svalbard).
In Iceland: Akureyri.
In Russia: Murmansk, Arkhangelsk, Dudinka, Tiksi, and Pevek.

Arctic Shelves

The Arctic Ocean has several continental shelves. These are underwater extensions of the continents. The Russian continental shelf is very large. It is sometimes called the "Arctic Shelf." This shelf holds large amounts of oil and natural gas. The edge of the Chukchi shelf forms part of the border between Russia and the United States. Many countries have claims to these Arctic territories and their resources.

Underwater Features

An underwater mountain range, called the Lomonosov Ridge, divides the deep Arctic Basin. It splits it into two main basins: the Eurasian Basin and the Amerasian Basin. The ocean floor has many features like ridges, flat plains, and deep areas. The average depth of the Arctic Ocean is about 1,038 meters. The deepest point is the Molloy Hole, which is about 5,550 meters deep.

Geology of the Arctic Ocean

The rocks under the Arctic Ocean have a long history. Over millions of years, sediments built up, creating places where oil and gas can be found today. The opening of the Atlantic Ocean also led to the formation of the Arctic Ocean. This happened as new oceanic crust formed.

Because of the ice and remote conditions, the geology of the Arctic Ocean is still being explored. Scientists believe there are large oil and gas reserves under the ice.

Oceanography: Water and Ice

Water Flow in the Arctic Ocean

A diagram showing how different water masses are layered in the Arctic Ocean.

In much of the Arctic Ocean, the top layer of water is less salty and colder. This layer is about 50 meters deep. It stays stable because saltiness affects density more than temperature. This top layer gets fresh water from large rivers in Siberia and Canada. This fresh water floats on top of the saltier, denser ocean water below. Below this, there's a layer called the halocline. In the halocline, both saltiness and temperature increase as you go deeper.

Graphs showing how temperature and saltiness change with depth in different parts of the Arctic Ocean.

The Arctic Ocean has a unique water flow system. Water enters from both the Pacific and Atlantic Oceans. It forms three main water masses. The deepest is Arctic Bottom Water, found below 900 meters. It's the densest water in the world. It forms from cold shelf waters and Greenland Sea Deep Water. This dense water sinks and flows out, helping to form Atlantic Deep Water. This process is important for global ocean currents and climate.

A small crustacean called a copepod, which is important food for other animals in the ocean.

Between 150 and 900 meters deep is Atlantic Water. This water flows in from the North Atlantic Current. It cools and sinks, forming a deep layer that circles the Arctic Basin. This is the largest inflow of water into the Arctic Ocean. It is warmer than the surface water but stays submerged because of its saltiness. Strong winds push water into a large circular current called the Beaufort Gyre.

The Kennedy Channel, a waterway in the Arctic.

The top layer, Arctic Surface Water, is found from 0 to 200 meters deep. It includes a sub-surface layer that acts as a heat shield. This layer helps protect the surface from the warmer Atlantic water below.

In recent decades, warmer Atlantic water has been melting sea ice in the eastern Arctic. This shows how changes in ocean currents can affect the ice.

Water from both the Pacific and Atlantic Oceans flows out through the Fram Strait. This strait is between Greenland and Svalbard Island. The movement of sea ice is also a key part of Arctic Ocean circulation. Winds and pressure systems, like the Beaufort High, drive the ice movement. These patterns change with the seasons.

Sea Ice in the Arctic

Sea ice cover in the Arctic Ocean, showing how it changed between 2005 and 2007 compared to the average.

Much of the Arctic Ocean is covered by sea ice. Its size and thickness change throughout the year. The amount of Arctic sea ice has been shrinking steadily for decades. It declines by about 12.85% each decade since 1980. The ice cover is largest in April and smallest in September. Winds and ocean currents can move and rotate large areas of ice. Sometimes, ice piles up to form thick pack ice.

A Twin Otter plane being refueled on the pack ice in the Arctic Ocean during a flight to the North Pole.

Icebergs sometimes break off from northern Ellesmere Island. Glaciers in Greenland and Canada also form icebergs. Icebergs are not sea ice, but they can get stuck in the pack ice. Icebergs are dangerous for ships. The famous Titanic sank after hitting an iceberg. The ocean is mostly blocked by ice from October to June. Ships can also get covered in ice from October to May. Before modern icebreakers, ships risked getting trapped or crushed by the sea ice.

Climate of the Arctic Ocean

The Arctic Ocean has a polar climate. This means it's always cold, with small changes in temperature throughout the year. Winters have the polar night, which means continuous darkness. They are extremely cold with stable weather. Summers have continuous daylight, known as the midnight sun. Air temperatures can rise slightly above 0°C. It is cloudy year-round.

The surface water temperature of the Arctic Ocean is usually around -1.8°C. This is close to the freezing point of seawater. Unlike fresh water, seawater gets denser as it gets colder, so it sinks. The top 100-150 meters of ocean water must cool to freezing for sea ice to form. In winter, the relatively warm ocean water helps keep the temperatures from getting as extreme as in Antarctica.

The amount of pack ice covering the Arctic Ocean changes a lot seasonally. Most of the pack ice is also covered in snow for about 10 months a year. The deepest snow cover is in March or April.

The Arctic region's climate has changed a lot over Earth's history. Millions of years ago, it was much warmer. For example, 55 million years ago, the average annual temperature was 10-20°C. The surface waters were warm enough to support tropical life forms.

Today, the Arctic region is warming twice as fast as the rest of the planet.

Biology: Life in the Arctic Ocean

Three polar bears near the North Pole.

The Arctic Ocean has long periods of midnight sun and polar night. This means that plants and tiny organisms that make their own food, like ice algae and phytoplankton, can only grow in spring and summer. Small animals called zooplankton, especially copepods and euphausiids, eat these tiny plants. These small animals are a key food source for larger animals.

The types of animals higher up the food chain vary across the Arctic. In the Barents Sea, you find fish like herring and young cod. In ice-covered areas, polar cod are important predators. The top predators in the Arctic Ocean are marine mammals. These include seals, whales, and polar bears, which hunt fish.

A Minke whale swimming in the ocean.

Endangered marine species in the Arctic Ocean include walruses and whales. The Arctic has a delicate ecosystem. It is especially affected by climate change because it is warming faster than other parts of the world. Lion's mane jellyfish are common here.

Walruses resting on an Arctic ice floe.

Natural Resources of the Arctic

The Arctic region is rich in natural resources. These include oil and natural gas fields. There are also deposits of minerals, sand, and gravel. The ocean is home to many fish, seals, and whales.

The central part of the Arctic Ocean is a focus of interest for several countries. These include the United States, Russia, Canada, Norway, and Denmark. This area is important because it may hold a large portion of the world's undiscovered oil and gas.

Environmental Concerns in the Arctic

Arctic Ice Melting

The Arctic ice pack is getting thinner. A seasonal hole in the ozone layer also often appears. When the Arctic sea ice shrinks, the planet reflects less sunlight. This can lead to more global warming. Scientists predict that the Arctic could become ice-free in the summer by 2040. The last time the Arctic was ice-free was possibly thousands or even millions of years ago.

Warmer temperatures in the Arctic could cause a lot of fresh meltwater to flow into the North Atlantic. This might disrupt global ocean currents. Such changes could lead to serious shifts in Earth's climate.

As sea ice decreases and sea level rises, storms have a greater impact on open water. Stronger storm surges can also damage plants along the coast, such as in the Mackenzie River Delta.

Global warming has also led to more encounters between polar bears and humans. With less sea ice, polar bears search for new food sources. In late 2018 and early 2019, many polar bears entered towns in Novaya Zemlya, Russia. This caused local authorities to declare a state of emergency.

Methane Release

Sea ice and cold conditions help keep methane deposits stable. These deposits are found on and near the shoreline. If the ice melts, large amounts of methane could be released into the atmosphere. Methane is a powerful greenhouse gas. This could cause even more warming.

Other Environmental Issues

Other environmental concerns in the Arctic Ocean include radioactive contamination. This comes from sources like Russian radioactive waste sites in the Kara Sea. It also comes from Cold War nuclear test sites and contaminants from Camp Century in Greenland.

To protect the Arctic, five nations (United States, Russia, Canada, Norway, and Denmark/Greenland) signed an agreement in 2015. They agreed not to fish in a large zone in the central Arctic Ocean. This is until more is known about the marine resources and a system is in place to protect them.