A fjord is a long, deep, narrow body of water that reaches far inland. Fjords are often set in a U-shaped valley with steep walls of rock on either side.

Fjords are found mainly in Norway, Chile, New Zealand, Canada, Greenland, and the U.S. state of Alaska. Sognefjorden, a fjord in Norway, is more than 160 kilometers (nearly 100 miles) long.

Fjords were created by glaciers. In the Earth's last ice age, glaciers covered just about everything. Glaciers move very slowly over time, and can greatly alter the landscape once they have moved through an area. This process is called glaciation.

Glaciation carves deep valleys. This is why fjords can be thousands of meters deep. Fjords are usually deepest farther inland, where the glacial force was strongest.

Some features of fjords include coral reefs and rocky islands called skerries.

Some of the largest coral reefs are found at the bottom of fjords in Norway. They are home to several types of fish, plankton and sea anemones. Some coral reefs are also found in New Zealand. Scientists know much less about these deep, cold-water reefs than they do about tropical coral reefs. But they have learned that the living things in cold-water reefs prefer total darkness. Organisms in cold-water reefs have also adapted to life under high pressure. At the bottom of a fjord, the water pressure can be hundreds or even thousands of kilograms per square meter. Few organisms can survive in this cold, dark habitat.

Skerries are also found around fjords. A skerry is a small, rocky island created through glaciation. Most of the Scandinavian coastline is cut into thousands of little blocks of land. These jagged bits of coastline are skerries. The U.S. states of Washington and Alaska also have skerries.

Even though skerries can be hard to get around in a boat, fjords are generally calm and protected. This makes them popular harbors for ships.

fjord
Most fjords are deeper than the coastal sea into which they empty.

Scary Skerries
Skerries are a navigation challenge for boaters. Trying to travel around these disruptive islands, located in a narrow space, can be like making your way through a minefield!

coral reef
Noun

rocky ocean features made up of millions of coral skeletons.

Noun

long, narrow ocean inlet between steep slopes.

glaciation
Noun

process of a glacier carving out a landscape.

Noun

mass of ice that moves slowly over land.

Noun

part of a body of water deep enough for ships to dock.

ice age
Noun

long period of cold climate where glaciers cover large parts of the Earth. The last ice age peaked about 20,000 years ago. Also called glacial age.

Plural Noun

(singular: plankton) microscopic aquatic organisms.

ria
Noun

low, wetland area near the mouth of a river. Rias are often called "drowned river valleys."

Scandinavia
Noun

region and name for some countries in Northern Europe: Iceland, Norway, Sweden, Finland, and Denmark.

sea anemone
Noun

type of marine animal related to corals and jellies.

skerry
Noun

small, rocky island in a fjord.

tropical
Adjective

existing in the tropics, the latitudes between the Tropic of Cancer in the north and the Tropic of Capricorn in the south.

valley
Noun

depression in the Earth between hills.