Gulf of Thailand

The Gulf of Thailand is a big part of the sea.

It sits near lands like Thailand and Vietnam.

Many rivers flow into the sea. This brings fresh water to the gulf. The water stays warm and blue.

You might see whales swimming there. There are also sea turtles in the water. It is a busy place for many animals.

Long ago, the sea was much lower. There was no salt water there then. A big lake sat in its place.

People like to visit the islands. They go there to dive and see the reefs. It is a very special place.

The Gulf of Thailand is a large part of the sea.

It sits near the coasts of Thailand, Cambodia, Vietnam, and Malaysia. The gulf opens into the South China Sea in the southeast.

The water here is quite shallow. Most of the area is not very deep. Many big rivers flow into the gulf. These rivers bring fresh water to the sea. This makes the salt levels in the water lower.

Many animals live in these warm waters. You might see sea turtles swimming by. People also go there to watch whales. Some whales, like Eden's whale, live in this area.

There are also dugongs and dolphins.

Long ago, the world was very different. The sea level was much lower. There was no salt water in the gulf then. Instead, a giant lake of fresh water sat there.

This happened during a time called the Last Glacial Maximum.

Many people visit the islands for fun. They like to dive to see coral reefs. Some spots, like the Samaesan Hole, are very deep.

This makes it a place for expert divers.

The Gulf of Thailand is a large, shallow part of the sea.

It sits next to the coasts of Thailand, Cambodia, Vietnam, and Malaysia. This body of water opens up into the South China Sea in the southeast. Many people once called it the Gulf of Siam. This was because the country was named Siam for a long time. The name changed to Thailand in 1939. Now, the name Gulf of Thailand is the official one used by experts.

The water in the gulf is not very deep. Most of it is quite shallow, with an average depth of only 45 meters. This shallow water makes the exchange of water very slow. Large rivers like the Chao Phraya and the Mae Klong flow into the gulf. These rivers bring in a lot of fresh water. This lowers the amount of salt in the sea. The salt level stays between 3.05 and 3.25 percent. Only the deeper parts have water with more salt.

Long ago, the world looked very different. Between 26,000 and 20,000 years ago, the Earth was in a time called the Last Glacial Maximum. Huge ice sheets made the sea levels much lower. The sea level was about 125 meters lower than it is today. Because of this, there was no saltwater in the gulf. Instead, a giant lake of fresh water sat there. The land was even connected to islands in Indonesia.

Many amazing animals live in these warm tropical waters. You might see five different kinds of sea turtles swimming here. Some people visit just to watch whales in the sea.

You can find Eden's whales and Chinese white dolphins there. Dugongs also live in this area. However, the animals face hard jobs today. Plastic trash and oil spills can hurt them. Scientists found that at least 300 sea animals die from eating plastic each year.

People from all over the world visit the gulf for fun. They love to visit beautiful islands like Ko Samui and Ko Pha Ngan. Many people enjoy diving to see the colorful coral reefs. Some divers look for the Samaesan Hole.

This is the deepest dive site in the gulf. It is a very famous spot for expert divers. Some people call it one of the most extreme dive sites in the world. This is because the currents can be very strong.

The Gulf of Thailand is a large, shallow inlet of the South China Sea.

It sits between the southwestern shores of Mainland Southeast Asia and the northern Malay Peninsula. The gulf is bordered by Thailand to the north, west, and southwest. Cambodia lies to the northeast, and the Mekong Delta region of Vietnam is also nearby. The water opens into the South China Sea in the southeast. This body of water covers a seabed area of 304,000 square kilometers. It is a vital part of the regional geography and marine environment.

The physical nature of the gulf is defined by its shallow depth. The mean depth is only 45 meters. The maximum depth reaches only 85 meters. This shallowness causes water exchange to be quite slow. Large rivers flow into the gulf and change its chemistry. The Chao Phraya and Tha Chin rivers feed the Bay of Bangkok. The Mae Klong and Bang Pakong rivers also empty into this bay. The Tapi River flows into Bandon Bay in the southwest. These rivers bring massive amounts of fresh water into the sea. This inflow reduces the salinity, or salt level, to between 3.05 and 3.25 percent. Only the deeper water receives saltier water at 3.4 percent from the South China Sea.

Beneath the surface, the seabed has a unique shape called morphology. In the central depression, the floor is not flat. It features elongated mounds and ridges that run parallel to the basin. These shapes exist in water deeper than 50 meters. They cover tens of thousands of square kilometers. This pattern comes from a process called sediment dewatering. This occurs when fluid seeps out of the mud. This seepage creates small pits and pockmarks on the floor. Over time, bottom currents erode these pockmarks. This erosion turns the pits into long runnels and depressions. Eventually, these processes create the large fields of ridges seen today.

The history of the gulf involves major changes in both maps and names. It was originally known as the Gulf of Siam. This name came from the historical kingdom of Siam. The term "Siam" likely comes from the Sanskrit word "Syama," meaning dark or brown. Western maps used this name for centuries. In 1939, the country officially changed its name to Thailand. Following this, the name Gulf of Thailand became the official term. The International Hydrographic Organization now recognizes this name. Older maps from the Renaissance period sometimes called it the "Great Gulf." This was based on the Latin name "Sinus Magnus."

Geological history shows that the gulf looked very different in the past. During the Last Glacial Maximum, between 26,000 and 20,000 years ago, the world was much colder. Massive ice sheets in the Northern hemisphere lowered global sea levels by about 120 meters. Because the maximum depth of the gulf is only 85 meters, it was once dry land. There was no seawater in the gulf during this time. Instead, a great lake filled with fresh water from rain and rivers. This landmass was part of a larger area called Sundaland. Sundaland connected Mainland Southeast Asia to the islands of Indonesia. This connection disappeared when sea levels rose about 15,000 years ago.

The gulf is a home to many diverse marine species. Five types of sea turtles live here, including the green turtle and leatherback turtle. Many people visit for whale watching to see Eden's whales and dugongs.

However, the environment faces serious challenges. Coral reefs cover 75,590 rai, but only five percent are in fertile condition. In 2010, severe coral bleaching occurred across many sites. Bleaching happens when water temperatures stay above 30 degrees Celsius for over three weeks. Plastic pollution is also a major problem for marine life. At least 300 sea animals die each year from eating plastic trash.

Human activity and tourism also shape the gulf. Many tourists visit islands like Ko Samui and Ko Pha Ngan. Divers travel to find the Samaesan Hole near Samae San Island.

This is the deepest dive site in the gulf. It is known as an extreme site due to unpredictable currents and unexploded ordnance. The gulf is also important for fishing. Thailand catches 41 percent of its total marine catch in these waters. However, the coastline faces issues like severe erosion. Some areas lose more than five meters of coastline every year. This is partly due to the clearing of mangrove forests for shrimp farms.