Yellow Sea

The Yellow Sea is a marginal sea located in the Western Pacific Ocean.

It sits between mainland China and the Korean Peninsula. This body of water is considered the northwestern part of the East China Sea. The sea is divided into two main sections. The innermost bay in the northwest is the Bohai Sea. The northeastern extension is known as the Korea Bay.

The sea is famous for its distinctive color. Its name comes from the golden-yellow appearance of the water. This color is caused by large amounts of silt and sand. These sediments are carried into the sea by major rivers.

Several large rivers contribute to the sea's sediment levels. In the Bohai Sea, the Yellow River, the Hai River, and the Liao River flow. The Yellow River passes through Shandong province and its capital, Jinan. The Hai River flows through Beijing and Tianjin. In the Korea Bay, the Yalu, Chongchon, and Taedong rivers discharge into the sea. These rivers deliver brown sediment that colors the water.

This sediment also provides nutrients for the ocean. These nutrients can cause blooms of blue-green phytoplankton. Such blooms create visible swirls in the water. The sea floor is dominated by these river-brought deposits of sand and silt.

Geologically, the Yellow Sea is a flooded section of a continental shelf. It formed approximately 10,000 years ago. This happened after the last glacial period when sea levels rose. The sea is relatively shallow compared to other oceans. Its average depth is only 44 meters. The maximum depth reaches about 152 meters. The depth generally increases as you move from north to south. The water temperature and salinity remain mostly the same throughout its depth. However, the surface layers change during different seasons.

The climate of the region is defined by strong seasonal shifts. Winters are cold and dry. From late November to March, strong northernly monsoons blow across the area. In the northern parts, water temperatures can drop close to freezing. This causes drift ice and continuous ice fields to form. These ice patches can make navigation difficult between November and March. Summers are warm and wet. Frequent typhoons occur between June and October. The average annual precipitation increases from the north to the south.

The sea features unique tidal and current patterns. It has semidiurnal tides, which means the water rises twice a day. The tidal amplitude varies, but tides are typically higher at the Korean Peninsula. The tidal system rotates in a counterclockwise direction. The fastest tidal currents occur in the Myeongnyang Strait. This strait is located between Jindo Island and the Korean Peninsula. A famous phenomenon occurs here twice a year. In May and June, a land pass opens between Jindo and Modo islands for about an hour.

This event is known as the Jindo Sea Parting.

Biological productivity in the Yellow Sea is very high. The sea is rich in seaweed, such as kelp. It also supports many cephalopods, crustaceans, and shellfish. The southern waters are particularly productive. This area contains a massive belt of intertidal mudflats. These flats are vital for migratory birds. At least two million birds pass through the area during northward migration. This makes it a critical site in the East Asian–Australasian Flyway.

However, land reclamation has removed 65% of the intertidal area between the 1950s and 2002.

Human activity is very intense around the Yellow Sea. The coasts are densely populated.

For centuries, ships from China, Korea, and Japan have fished these waters. There are about 200 species used for commercial fishing. These include sea bream, mackerel, and squid. Unfortunately, many species are currently overfished. The sea is also a major route for navigation. Large ports like Dalian, Tianjin, and Incheon handle much of the traffic. The sea supports significant maritime trade and naval operations.