by Toshimitsu Nakashima and Takayoshi Toyota, Japan Marine Science and Technology Center;
Mitsuaki Yamaguchi,Deep Seawater Laboratory of Kochi Prefecture Japan
Deep seawater is nutrient-rich, cold, and pathogen-free which can be all advantageous for a lot of utilization such as mariculture, air conditioning, freshwater production and electric power generation, and which is renewable and environmentally clean.
A land-based experimental facility, "Kochi Artificial Upwelling Laboratory (KAUL)" to accumulate knowledge / know-how for understanding and utilization of deep seawater characteristics was constructed in March 1989 at Cape Muroto of Kochi Prefecture, Japan.
The deep seawater pipeline is hard polyethylene tube with an inner diameter of 125mm, which runs a total of 2,650m. The pump system is capable of pumping 460 cu m per day each of deep seawater and surface water from depths of 320m and 5m, respectively. Deep seawater reaching the land facility is about 13¢XC and contains about 28 µ M of NO3 throughout the year.
Under participation of public research organizations, universities, and companies, upwelled deep seawater is now being used for a wide range of applications in research and development, which include mariculture, desalination to produce fresh water, economical temperature control of seawater, air cooling for office. It was proved that deep seawater is effective for culture of micro- and macro-algae, rearing of fish and shellfish, and economical temperature control of seawater.