The Gulf of Mexico is a large body of water located off the southeastern coast of North America. With a surface area of approximately 600,000 square miles, it ranks among the largest semi-enclosed ocean basins on Earth. However, the Gulf of Mexico is not the single largest body of water in the world.
What is the Gulf of Mexico?
The Gulf of Mexico is considered a marginal sea of the Atlantic Ocean. It is bounded by the southern coasts of the U.S. states of Florida, Alabama, Mississippi, Louisiana, and Texas to the north, the eastern coast of Mexico to the west and south, and the island of Cuba to the southeast. The shape of the Gulf’s basin is roughly oval and is approximately 810 nautical miles wide and filled with sediment washed down by over 30 major rivers, the largest of which is the Mississippi River.
The Gulf was formed approximately 300 million years ago as part of the break-up of the supercontinent Pangaea. It is connected to the Atlantic Ocean through the Florida Straits between Florida and Cuba, and with the Caribbean Sea via the Yucatan Channel between Mexico and Cuba. The narrow connection between the Gulf and the Atlantic, along with its enclosed nature, limit the normal water circulation of the Gulf basin and the oceanic interchange of biota.
How big is the Gulf of Mexico?
The total surface area of the Gulf of Mexico is estimated to be around 600,000 square miles (1,550,000 sq km). By comparison, here are the surface areas of some other major bodies of water:
- Pacific Ocean – 63.8 million square miles
- Atlantic Ocean – 41.1 million square miles
- Indian Ocean – 28.4 million square miles
- Southern Ocean – 7.8 million square miles
- Arctic Ocean – 5.4 million square miles
- South China Sea – 1.4 million square miles
- Caribbean Sea – 971,000 square miles
- Gulf of Mexico – 600,000 square miles
- Gulf of California – 62,000 square miles
So while the Gulf of Mexico has a substantial surface area, it ranks only 8th in size compared to the major bodies of water and oceans across the globe.
Largest lakes and inland seas
When comparing the size of the Gulf of Mexico to other inland bodies of water and marginal seas, it ranks among the largest:
| Body of water | Surface area (sq mi) |
|---|---|
| Caspian Sea | 143,200 |
| Lake Superior | 31,700 |
| Lake Victoria | 26,828 |
| Lake Huron | 23,010 |
| Gulf of Mexico | 600,000 |
As this table shows, the Gulf of Mexico has by far the largest surface area compared to lakes and other inland seas. The Caspian Sea is the closest at 143,200 square miles, making the Gulf over 4 times larger.
Deepest areas of the Gulf
While the Gulf of Mexico covers a large surface area horizontally, its overall depth is relatively shallow compared to the major oceans. The mean water depth of the Gulf is approximately 1.5 miles (2.4 km). The deepest areas include:
- Sigsbee Deep – 14,383 feet (4,384 m)
- Campeche Canyon – 12,190 feet (3,715 m)
- Bay Marchand – 12,035 feet (3,676 m)
By comparison, the maximum depth of the Pacific Ocean at the Mariana Trench is 36,070 feet (10,994 m) – over twice as deep as the deepest areas of the Gulf of Mexico.
Water volume
While depth is limited, the Gulf of Mexico still contains a massive total volume of water. Estimates put the total water volume at approximately 660 quadrillion gallons (2.5 million cubic km).
For perspective, this is enough water to fill around 1 trillion Olympic-sized swimming pools. It pales in comparison, however, to the total water volume of the world’s oceans, which is approximately 321 million cubic miles (1.3 billion cubic km).
Sources of water
The primary source of water entering the Gulf of Mexico is precipitation, receiving an annual input of approximately 1.4 x 1015 gallons (530 cubic km) of water. Rivers, predominantly the Mississippi River, account for another 15% of the total input. Additional sources include runoff, groundwater discharges, and seawater exchanged with the Caribbean Sea and Atlantic Ocean.
Major rivers flowing into the Gulf
Here are some of the major rivers that drain into the Gulf of Mexico:
- Mississippi River – drains 31 U.S. states and 2 Canadian provinces
- Rio Grande – forms border between Texas and Mexico
- Pearl River – runs through Mississippi and Louisiana
- Mobile River – runs through Alabama
- Apalachicola River – runs through Florida
- Brazos River – runs through Texas
- Colorado River – flows from Texas into Mexico
Circulation patterns
The connecting straits to the Atlantic Ocean and Caribbean Sea allow for circulation between these bodies of water. The Yucatan Channel between Mexico and Cuba allows transport of the Loop Current into the Gulf of Mexico. The warm waters of the Loop Current circulate clockwise through the Gulf before exiting out the Florida Straits and joining the Gulf Stream.
In addition to the Loop Current, water circulation within the Gulf includes smaller gyres and eddies, as well as tidal movements. The average surface current speeds range from 0.5-2 knots.
Major currents
Here are some of the major ocean currents influencing circulation in the Gulf of Mexico:
- Loop Current – main current entering from Caribbean Sea and circulating clockwise in Gulf
- Florida Current – flows towards the Florida Straits near Miami and joins the Gulf Stream
- Cuba Current – flows northwestward along Cuba’s coast
- Yucatan Current – flows northward along the Yucatan Peninsula
- Mexican Current – flows counterclockwise off Mexico’s eastern coast
Sizes of other marginal seas
Here is how the Gulf of Mexico compares in size to some other marginal seas of the world:
| Marginal sea | Surface area (sq mi) |
|---|---|
| Mediterranean Sea | 969,100 |
| South China Sea | 1,400,000 |
| Bering Sea | 872,000 |
| Sea of Okhotsk | 613,000 |
| Gulf of Mexico | 600,000 |
| Hudson Bay | 479,000 |
So while the Gulf of Mexico is large, the Mediterranean Sea and South China Sea exceed it in total surface area. However, it remains much larger than many other marginal seas around the world.
Unique characteristics of the Gulf
Despite not being the largest body of water globally, the Gulf of Mexico has many distinctive characteristics including:
- Large drainage basin covering over 40% of the U.S.
- Enormous river inflows, especially the Mississippi River discharge
- Large continental shelf along its perimeter
- Abundant petroleum reserves located offshore
- Home to flowering red tides caused by algal blooms
- Spawns severe hurricanes during summer and fall months
Economic importance
The Gulf of Mexico has huge economic importance to the surrounding countries and states. Major activities and industries include:
- Offshore oil and gas – Extensive offshore rigs and platforms throughout the Gulf, especially off Texas and Louisiana
- Commercial fishing – 15% of the US domestic commercial fishing catch comes from the Gulf
- Cruise tourism – Major cruise ship ports in New Orleans, Galveston, Tampa, and Miami
- Military operations – Significant naval operations conducted in the Gulf by the US
- Merchant shipping – Busy ports handling cargo include New Orleans and Houston
The Gulf Coast also accounts for a huge portion of the U.S. refining capacity, handling approximately half of the country’s crude oil. Offshore oil alone provides 20% of US domestic oil production.
Conclusion
In conclusion, while the Gulf of Mexico is certainly massive in scale, spanning 600,000 square miles, it does not qualify as the single largest body of water in the world. That superlative belongs to the immense Pacific Ocean, which is more than 100 times larger. However, the Gulf remains the 9th largest body of water and the largest marginal sea in the Atlantic. Its enormous drainage basin, river flows, economic resources, and unique biodiversity solidify its status as one of the most important marine regions on the planet.
