Generally, DSW is present in the deep sea about 200m below sea level where sunlight cannot reach (and thus organic matter cannot be produced). It has almost no organic matter or pathogens, and maintains low temperatures at stable levels throughout the year. It is rich in nutritive salts that are essential for growth in marine plants and has a good mineral balance. From the viewpoint of marine ecology, it is said that the decomposition (mineralization) rate of organic matter is higher than the rate of organic matter production by photosynthesis, and it is found below the compensation depth where vertical mixing and anthropogenic pollution occur at low rates. In other words, DSW is a useful marine resource having characteristics of low temperature, cleanliness, stability, rich nutrients and aging, and a vast clean resource that is generated and circulated as seawater in the cycles of matter where sunlight is used as the energy source.
DSW is low-temperature seawater that maintains low temperatures below 2℃ throughout the year. This characteristic makes it useful in cooling, refrigeration and ice making as well as production and culture of coldwater fish and shellfish seeds.
DSW is seawater rich in inorganic nutrients (nitrogen, silicon, phosphate, etc.) necessary for the growth and development of marine plants (photosynthetic algae). This characteristic makes it useful in cultivating agricultural and fisheries products for functional food and drug development and cultivating phytoplankton and zooplankton.
DSW is clean seawater containing little to no pathogens or harmful substances. It is not contaminated with any general bacteria such as E. coli, contains few marine bacteria compared with the surface water, and has low amounts of suspension, periphyton and sessile organisms. Thus, it is clean and safe to drink and can be used in aquaculture and food production, in addition to being used to supply clean, high-quality water for livestock and for fish preserves in summer.
The water quality of DSW does not fluctuate much and is stable in terms of physicochemical and biological characteristics from year to year.