Arctic Ocean

The Arctic Ocean is very cold.

It is the smallest ocean in the world. Much of the water is covered by ice.

In the winter, the ice covers almost everything. The ice melts in the summer. This makes the water less salty. This ocean is a very big place.

It is surrounded by many lands. It sits at the very top of our world.

The Arctic Ocean is the smallest ocean on Earth.

It is also the shallowest and coldest ocean. It sits at the very top of our world. Much of the water stays covered by sea ice. In the winter, the ice covers almost everything.

In the summer, the ice begins to melt. This melting makes the water less salty. The ocean has the lowest salinity of all major oceans. This happens because rivers pour fresh water into it. It also happens because there is not much evaporation.

The ocean is surrounded by many lands. These include North America and Eurasia. It also sits near Greenland and Iceland. Deep under the water, there are large ridges. One is the Lomonosov Ridge. This ridge splits the deep sea into two parts. The deepest spot is called Molloy Hole. It is about 5,550 meters deep.

The Arctic Ocean is a very special part of our world. It is the smallest and shallowest of the five major oceans.

It is also the coldest ocean on Earth. This ocean sits at the very top of the world. It covers a huge area of about 14,060,000 square kilometers. Some scientists call it the North Polar Sea. Others think of it as an estuary of the Atlantic Ocean.

Many things happen to make this ocean work the way it does. Much of the surface is covered by sea ice throughout the year. In the winter, the ice covers almost the entire ocean.

The water changes as the ice melts and freezes each season. The Arctic Ocean has the lowest salinity, or saltiness, of the major oceans. This happens because many rivers pour fresh water into it. There is also very little evaporation to leave salt behind.

Humans have lived near this cold ocean for a very long time. People moved into North America as far back as 50,000 years ago. They crossed a land bridge that once joined Siberia to Alaska.

Many different groups lived there, like the Dorset and the Thule people. The Thule were the ancestors of the modern Inuit people. These groups have lived in places like Greenland and Alaska for many centuries.

Explorers have spent hundreds of years trying to learn about this place. In 325 BC, a man named Pytheas traveled north to a land called Thule. He saw water that was like a thick, frozen substance. Later, people thought there might be an "Open Polar Sea" with no ice. They were wrong, as explorers found thick ice instead. In 1893, Fridtjof Nansen made the first nautical crossing of the ocean.

Today, we use satellites to watch the ocean every single day. These tools show us that the sea ice is shrinking. In September 2012, the ice reached a new record minimum.

The ocean also has deep parts under the waves. An underwater ridge called the Lomonosov Ridge divides the deep sea. The deepest spot is the Molloy Hole, which is 5,550 meters deep.

The Arctic Ocean is the smallest and shallowest of Earth's five major oceans.

It covers an area of approximately 14,060,000 square kilometers. This makes it nearly the same size as the continent of Antarctica. Because it is located at the North Pole, it is the coldest ocean on the planet. Some oceanographers refer to it as the North Polar Sea or the Arctic Mediterranean Sea. Others describe it as an estuary of the Atlantic Ocean.

Many physical processes determine the unique characteristics of this ocean. The Arctic Ocean has the lowest average salinity, or saltiness, of the five major oceans. This low salinity occurs because of heavy fresh water inflow from rivers and streams. Additionally, there is very little evaporation in this cold region. The ocean also has a limited connection to surrounding waters that have higher salinity. The surface temperature and salinity change seasonally as the sea ice melts and freezes.

The ocean is mostly covered by sea ice throughout the year. During the winter, the ice cover is almost complete. In the summer, the ice shrinks significantly. Data from the US National Snow and Ice Data Center (NSIDC) shows a continuous decline in sea ice extent. In September 2012, the ice reached a record minimum. During that time, the sea ice had diminished by 49% compared to the average extent recorded between 1979 and 2000.

Human history in the Arctic is very long. People inhabited the North American polar region between 17,000 and 50,000 years ago. During the Wisconsin glaciation, falling sea levels created a land bridge between Siberia and Alaska. This allowed people to move across and settle the Americas. Early groups included the Pre-Dorset and the Saqqaq culture. Later, the Dorset culture spread across North America. Eventually, the Thule people migrated from the Bering Strait. The Thule are the ancestors of the modern Inuit people.

Exploration of the Arctic has changed how we understand the world. In 325 BC, Pytheas of Massilia traveled north to a land he called "Eschate Thule." He described a congealed substance that made sailing and walking difficult. This was likely a description of loose sea ice. For a long time, many people believed in the myth of an "Open Polar Sea." Explorers like John Barrow and Elisha Kane searched for this open water. However, expeditions eventually proved that the polar ice cap is thick and stays year-round.

Significant milestones in Arctic travel have occurred throughout the 20th century. Fridtjof Nansen completed the first nautical crossing of the ocean from 1893 to 1896. In 1958, the submarine USS Nautilus made the first nautical transit of the North Pole. The first surface nautical transit was completed by the icebreaker NS Arktika in 1977. Wally Herbert led the first surface crossing by dog sled in 1969. Since 1937, Soviet and Russian manned drifting ice stations have monitored the ocean. These stations move with the ice floes across thousands of kilometers.

The geography of the ocean floor is quite complex. An underwater feature called the Lomonosov Ridge divides the deep North Polar Basin. This ridge creates two separate basins: the Eurasian Basin and the Amerasian Basin. The Eurasian Basin is between 4,000 and 4,500 meters deep. The Amerasian Basin is about 4,000 meters deep. The average depth of the entire Arctic Ocean is 1,038 meters. The deepest point is the Molloy Hole in the Fram Strait, which reaches 5,550 meters.

Geological activity has shaped the Arctic over millions of years. The mountains around the ocean formed during the Ellesmerian orogeny. During the Jurassic and Triassic periods, the region experienced subsidence. This led to the deposition of sediments that created oil and gas reservoirs. The Arctic Ocean opened as the supercontinent Pangea began to rift apart. This rifting extended northward and allowed oceanic crust to erupt. Today, the Siberian Shelf is the largest continental shelf in the world and holds large reserves of oil and gas.