Recently, the great increase of the world population has required greater food productivity. However, an expansion of farm production has been limited by the deforestation problem. In contrast, pelagic zone has large areas but has low biological productivity, as can be known by the figure on the right. One of the methods for the fertilization of ocean desert is an effective utilization of deep seawater. Therefore, we have proposed a plan to upwell the nutrient-rich seawater to upper ocean artificially. This is called "LAPUTA project".
As a method of upwelling, Perpetual Salt Fountain (for detail, go down) proposed by Stommel et al. (1956) is used. There are several advantages compared to other methods of artificial upwelling.
・ Does not require any energy input for artificial upwelling
・ Maintenance-free because of the simple structure
・ Low risk of damage by the ocean waves
・ Deep seawater does not descend after the upwelling
We have conducted several experiments at the area around Mariana trench, using the experimental apparatus shown on the right.
On 2002 (cruise KH02-2), measured the upwelling flow for the first time in the world, by using the research vessel Hakuho-maru (see figure below).
On 2004 (cruise KH04-2), succeeded in continuous measuring the upwelling flow.
In several parts of the ocean, salinity and temperature of the upper ocean is higher than those of the deep seawater. When a pipe is settled in such environment and filled with deep seawater, heat transfers through the pipe, then the temperature inside the pipe will be the same as outside. Finally, buoyancy occurs because the salinity inside the pipe is lower than that of outside at this time. One of the advantages of this upwelling method is that it does not require any energy input except for initial input to fill the deep seawater at the beginning.
This phenomenon was first presented in the journal of Deep-Sea Research (Stommel et al., 1956).
・KH-01, KH-02, KH-04, KH-05 and KH-09 in the Marian Trench (Hakuho-maru)
Perpetual Salt Fountain has been realized for the first time in the world.
・In Onagawa, Yriage (2009.3)and Tobishima(2010.9)
Canceled (Adverse weather)
・In Shizugawa(2010.11), Sado(2011.2 and 2011.8), Sagami Bay(2011.12)
Streamlined pipe and pipe installation method have been studied.
Title: A Study of Creation of Fishing Grounds in the Ocean area around Okinotori-shima by utilizing deep seawater (2007-2012.03)
Objective: Enhancement of the effect of the fishing grounds in the Okinotori-shima ocean area by deep seawater upwelling using perpetual salt fountain
