The Isthmus of Panama connects North and South America. It separates the Atlantic Ocean from the Pacific Ocean. The Panama Canal is one of the most strategic artificial waterways in the world and one of the most significant and challenging engineering projects ever undertaken.
Isthmus of Panama
The Isthmus of Panama, also historically known as the Isthmus of Darien, is the narrow strip of land that extends east-west about 640 km (400 mi) from the border of Costa Rica to the edge of Colombia.
The isthmus connects North America and South America. It separates the Caribbean Sea (Atlantic Ocean) from the Gulf of Panama (Pacific Ocean). It formed around 2.8 million years ago, separating the Atlantic and Pacific Oceans and causing the creation of the Gulf Stream.
The narrowest part of the Americas, approximately 50 - 200 km (30 - 120 mi) wide, the Isthmus of Panama today hosts the Republic of Panama and the Panama Canal. The terrain alternates between mountains, tropical rainforests, and coastal plains. Like many isthmuses, it is a location of great strategic value.
Twenty million years ago ocean covered the area where Panama is today. Then, there was a gap between the continents of North and South America through which the waters of the Atlantic and Pacific Oceans flowed freely, called the Central American Seaway, also known as the Panamanic Seaway, Inter-American Seaway, and Proto-Caribbean Seaway. This body of water once separated North America from South America.
The pressure and heat caused by this collision led to the formation of underwater volcanoes, some of which grew tall enough to break the surface of the ocean and form islands as early as 15 million years ago.
Over the next several million years, more volcanic islands filled the area. Meanwhile, the movement of the two tectonic plates was also pushing up the sea floor, eventually forcing some areas above sea level.
The formation of the Isthmus of Panama also played a significant role in the world's biodiversity. The seaway's closing allowed a significant land mammal migration between North and South America, known as the Great American Interchange.
This allowed species of mammals such as cats, canids, horses, elephants, and camels to migrate from North America to South America. At the same time, porcupines, ground sloths, glyptodonts, and terror birds made the reverse migration.
Scientists believe the formation of the Isthmus of Panama is one of Earth's most significant geologic events in the last 60 million years. Even though it is only a tiny sliver of land relative to the sizes of continents, the Isthmus of Panama had an enormous impact on Earth's climate and environment.
The closed seaway led to a different North Atlantic Ocean circulation, impacting the surrounding atmospheric temperatures and the glacial cycle.
The land bridge re-routed currents in the Atlantic and Pacific Oceans by shutting down the water flow between the two oceans. As a result, Atlantic currents were forced northward and eventually settled into a new current pattern that we call the Gulf Stream today.
With warm Caribbean waters flowing toward the northeast Atlantic, the climate of northwestern Europe grew warmer. Winters there would be as much as 10 °C (50 °F) colder in winter without transporting heat from the Gulf Stream.
The Atlantic, no longer mingling with the Pacific, also grew saltier. These changes helped establish the global ocean circulation pattern we see today.
Isthmus of Panama (NASA)
The Panama Canal is an artificial waterway that cuts across the Isthmus of Panama and connects the Atlantic and Pacific oceans. It is a lock-type canal owned and administered by the Republic of Panama.
It is one of the most strategic artificial waterways in the world and one of the most significant and most challenging engineering projects ever undertaken. The American Society of Civil Engineers has ranked the Panama Canal as one of the seven wonders of the modern world.
France began work on the canal in 1881 but stopped due to engineering problems and a high worker mortality rate. The United States took over the project in 1904 and opened the channel on August 15, 1914.
The Panama Canal shortcut significantly reduced the time for ships to travel between the Atlantic and Pacific Oceans, enabling them to avoid the long, hazardous cape route around the southernmost tip of South America via the Drake Passage or Strait of Magellan.
Ships sailing between the east and west coasts of the United States, which otherwise would be obliged to round Cape Horn in South America, shorten their voyage by about 15,000 km (8,000 nautical miles) by using the canal.
Savings of up to 6,500 km (3,500 nautical miles) are also made on voyages between one coast of North America and ports on the other side of South America.
Ships sailing between Europe and East Asia or Australia can save as much as 3,700 km (2,000 nautical miles) using the canal.
Map illustrating the Panama Canal and its locks