Even the Same Seawater Differs Between Surface Water and Deep Water [Reading Science]

Can the deep ocean water extracted from the East Sea of our country be considered a part of the deep ocean water circulating in the ocean?
Photo by YouTube screen capture

[Asia Economy Reporter Kim Jong-hwa] Surrounded on three sides by the sea, seawater is a common presence in our country. However, polluted seas near urban ports shatter even the illusion of a blue planet Earth.

Unlike this polluted seawater, water drawn from the deep sea, known as 'ocean deep water,' is highly valued. Why is that? Even though it is seawater, is there something different about water drawn from the deep sea?

Ocean deep water refers to seawater existing at depths of 200 meters or more, where sunlight barely reaches. So, can all seawater deeper than 200 meters below the sea surface be considered ocean deep water? By that calculation, about 92.5% of the Earth's seawater would be ocean deep water.

Not all seawater deeper than 200 meters is considered ocean deep water. Seawater near the surface, heavily influenced by precipitation, wind waves, and evaporation, is called 'surface water.' Among seawater deeper than 200 meters, only the circulating seawater is considered ocean deep water.

Ocean deep water is generated when seawater circulating worldwide in the Atlantic, Indian, and Pacific Oceans meets the cold glacial regions of Greenland in the North Atlantic or the Weddell Sea near Antarctica. Strictly speaking, ocean deep water refers to seawater resources originating from Greenland that circulate through the Atlantic, Indian, and Pacific Oceans on a 2,000-year cycle.

When seawater continuously circulating around the Earth reaches the glacial regions of Greenland, it becomes very cold and its density increases significantly. This denser seawater sinks below 200 meters, dropping to about 2℃.

This sinking seawater has a large density difference from the warm, high-salinity surface water, so they do not mix but maintain a boundary like oil and water, forming layers and circulating the Earth's oceans over 2,000 years. This water is ocean deep water.

Thanks to its cold temperature below 2℃ and deep depth, organic matter or pollutants do not enter, keeping it clean and rich in minerals and nutrients. Shallow seawater below 200 meters supports organic growth through photosynthesis and easily receives air and land pollutants, but these do not penetrate into the deep sea, allowing ocean deep water to remain clean while carrying abundant minerals.

Ocean deep water features low-temperature stability, oligotrophic characteristics rich in inorganic nutrients like nitrogen, phosphorus, and silicon, purity, and maturation formed over a long period under high pressure in the sea. Due to these characteristics, it is said that in Korea, ocean deep water can only be extracted from certain parts of the East Sea.

Marine Deep Water Belt of the East Sea Claimed by Domestic Marine Deep Water Companies [Image=(Joo) Global Deep Water]

Ocean deep water is used as a valuable resource in various industries, including aquaculture and breeding to increase and manage fishery resources, renewable energy utilizing its low temperature and temperature differences, drinking water, food, cosmetics, and pharmaceuticals. It is also used to increase agricultural productivity through oligotrophic properties and for organic crop cultivation.

It is especially used extensively in cosmetics, and some scientists have sparked interest by announcing that ocean deep water has a mineral balance most similar to amniotic fluid in a mother's womb. In Korea, ocean deep water is extracted from eight locations: Oho in Goseong County, Oeongchi in Sokcho City, Wonpo in Yangyang County, Jeongdongjin in Gangneung City, Chuam in Donghae City, Jeungsan in Samcheok City, Taeha in Ulleung County, and Hyeonpo in Ulleung County.

However, there is controversy that the ocean deep water of the East Sea is not strictly ocean deep water because it lies outside the ocean deep water belt of the open ocean. For ocean currents to pass into the East Sea, they must pass through the Korea Strait, whose deepest point is about 227 meters. Since the deepest point is only about that depth, the rest of the depth does not reach 200 meters, leading to claims that it is not strictly ocean deep water.

Ultimately, there are doubts about whether the ocean deep water of the East Sea can be considered part of the ocean deep water that slowly circulates the Earth's oceans over 2,000 years. The deep East Sea, with an average depth exceeding 1,000 meters, can be regarded as ocean deep water that fully retains the advantages of low temperature, high pressure, and oligotrophic characteristics of deep ocean water.

This content was produced with the assistance of AI translation services.