equatorial and Costa Rica Dome upwelling regions (Fig. 1). At all other offshore areas, 

 artificial upwelling will be required. To provide adequate nutrients to the plants, using a 

 reasonable upwelling volume, the upwelled water may need to contain some 20 to 30 fig-at 

 NOo/liter. In general, nutrient concentrations in the 20 to 30 ^g-at/liter range are found at 



deeper depths as one moves west from the coast and from north to south. The depth of the 

 30 Mg-at/liter NO3 level increases from 100-200 meters at 40-45°N to 250-350 meters at 



25-30°N along the west coast, and is at 350-500 meters off Hawaii. Other things being 

 equal, the greater the depth from which water must be pumped, the greater the costs in- 

 volved. The proposed pumping depth of 100 meters (Ref. 2) for a Phase 3 farm might 

 necessitate locating the farm above 40° N or very close to west coast upwelling areas within a 

 few kilometers from shore, or else pumping rates could possibly be increased somewhat 

 beyond the proposed five acre feet (six cubic kilometers) per day (Ref. 2). Upwelling pipes 

 might have to be 200-300 meters long off southern California in open ocean areas, and even 

 longer to the south or west to provide adequate concentrations of nutrients to the surface. 

 In the equatorial upwelling and Costa Rica Dome regions, it is possible that no artificial 

 upwelling would be needed because of the continual high concentration of nutrients at the 

 surface. Other factors, however, place these upwelling regions in doubt as potential farm 

 locations for the near term because of the relatively high current speed, temperature regime, 

 and remoteness from potential processing facilities. If, however, the OFEF concept of a 

 dynamically-positioned farm capable of movement with propulsors (Refs. 2 and 3) is tena- 

 ble, and at-sea processing and long-distance transportation become economically feasible, 

 then large floating farms in the equatorial region become a strong possibihty. The farms 

 could float to the east with the Equatorial Countercurrent, move south a few hundred kilo- 

 meters and move west with the South Equatorial Current, and then propulse north to the 

 Equatorial Countercurrent again, thus remaining in a limited area of the central eastern 

 Pacific and within high-nutrient waters. 



The requirement for nutrients at a given concentration may be a significant economic 

 factor because the costs increase with the depth of the required upwelling and the depth of 

 derived nutrient levels varies with area. Therefore, location of the OFEF with regard to 

 nutrients is more a question of economics than of Macrocystis requirements. Probably the 

 mo'it cost effective farm locations from the nutrient (near surface) availability standpoint 

 would be as follows: 



1. Equatorial Upwelling Zone (area 20), Costa Rica Dome, and Peruvian upwelling 

 regions ; 



2. Areas north of 40°N and coastal regions to 35°N (area 12); 



3. Coastal regions south of 35°N to 25°N (areas 1 1 and 1-9); 



4. Areas 10 and 18; and the 



5. Central eastern Pacific areas 13, 14, 15, 16, 17 and 19. 



Practically, for Phase 1 and 2 farms and early Phase 3 fanns, the areas included under 2 and 

 3 above are the most feasible from a nutrient viewpoint. 



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