RIASSUNTO
ABSTRACT:
This paper presents a brief review of recent researches on environmental impact assessment for pumping-up and discharging deep seawater, which is performed as a part of a national project driven by Japan Ocean Industries Association (JOIA). These researches focus on several environmental effects, such as biological entrainment, CO2 emission from power plant, cooling water discharge, and fertilization for phytoplankton and seaweed. The results of these assessments suggest that dominant environmental effects of pumping-up and discharging deep seawater are environmental benign, e.g. fertilization, and development of a proper discharging system is important.
INTRODUCTION
Deep seawater is cold, nutrient-rich and pathogen-free seawater found at depth of several-hundred meters or lower. The deep seawater has attracted special interest as a renewable resource for energy and marine primary production (Fast, 1991), and also been focused as the useful material for fresh water production, air conditioning/refrigeration, and so forth (Van Ryzin et al., 2000). The multiple productions based on this enormous renewable resource may result in environmental sustainability and economic viability (Daniel, 1992). In Japan, several deep seawater research laboratories and utilization facilities are operated, and over ten facilities are planned (Otsuka, 2001). These facilities investigate various deep seawater applications and their integrated systems. In addition, the pumping-up deep seawater are commercially distributed, and used for many deep seawater merchandises, such as drinks, foods, medical and health care uses, cosmetics, etc. Two national deep seawater projects for large-scale applications, which are driven by Japan Ocean Industries Association (JOIA) and Marino-Forum 21 (MF21), have recently started. JOIA project focuses on optimum design of an integrated deep seawater utilization system with cooling for steam-power plant (JOIA, 2000, 2001). In MF21 project, a prototype artificial upwelling machine is developed for enhancement of marine primary production (Ogiwara et al., 2001, Ouchi et al., 2001).