For example, during the fall in area 19, the thermocline is between 30 and 90 meters of 

 depth (Fig. B.77) and the nitrate concentration rapidly increases over this range (Fig. A. 18). 



Area 20 in the Peru-Galapagos water (Fig. 1) is in the equatorial region (2°S to 3°N) 

 west of the Galapagos Islands. This is an area of intense natural upwelling caused by a 

 strong divergence at the equator which acts to bring water of low temperature and high 

 nutrient concentration to the surface (Ref. 29). Figures 22 through 25 show nitrate- 

 nitrogen levels for winter and summer at a depth of 10 and 100 meters for a major portion 

 of the eastern tropical Pacific (Ref. 22). Ten-meter nitrate concentrations are highly elevat- 

 ed, averaging between 8 Mg-at N03/liter (winter, Fig. 22) and 10 Mg-at/hter (summer, Fig. 

 23). The equatorial upwelling region extends from the Peruvian and Ecuadorian coasts 

 (from about 12°S to the equator) and in the westeriy direction to at least 150°W (Figs. 1, 

 22, and 23). In region 20, 100-meter nitrate levels average from 15 to 25 /zg-at/liter for 

 winter (Fig. 24) and summer (Fig. 25). Concentrations as high as 40 jug-at/liter are observed 

 southeast of the Galapagos (8°N 86° W) during the winter months (Fig. 24). Figures A.20 

 through A. 24 give nitrate concentration profiles for area 20 for the four seasons. Surface 

 concentrations are variable but high (maximum of 14 /ig-at/liter in summer. Fig. A.21). Be- 

 cause of the upwelling, surface temperatures are significantly depressed (Figs. 9 and 10); 

 during the summer and fall mean temperatures are 6° to 7°C lower in region 20 than in 

 region 19 (Appendices B and C). Reduced temperatures and increased nutrients in the 

 natural upwelling zones would, of course, allow for much reduced artificial upwelling rates 

 and possibly eliminate the need for upwelling completely. 



In summary, nutrient concentrations in the surface waters of the eastern Pacific 

 Ocean are highly variable. Concentrations of nitrate-nitrogen are usually higher over the 

 continental shelf because of localized upwelling and increased nutrient input from terrestrial 

 runoff. Generally, nitrate concentration decreases in a westerly direction and the isonutri- 

 ent depths increase. For example, in regions 1 through 9 the 30 yug-at/liter NO3 depth is 



between 200 and 300 meters, in region 18 it is 250-300 meters, and near Hawaii (region 14) 

 it is 325-500 meters. The trend is similar from north to south; there are higher surface 

 concentrations seasonally north of 35°N. In more temperate waters (south of 35°N to 

 about 3°N) surface concentrations of nitrate are generally below 1 /zg-at/liter and frequently 

 below the level of detection. In the Costa Rica Dome and equatorial upwelHng regions, 

 surface nitrate levels run as high as 8 to 10 ;ug-at/liter and reach levels of 20 to 25 /xg-at/hter 

 in the upper 100 meters. 



METEOROLOGY 



The meteorological parameters of greatest significance to OFEF, probably are wind 

 velocity and duration. Severe storms with high velocity winds cause high waves and in- 

 creased current speeds, which in turn can create increased stresses on substrate structures 

 and kelp plants. Because wave heights and periods are related to wind speed, wind and 

 storm characteristics are considered in this section. The ocean, as a Hquid medium, is great- 

 ly influenced by severe stornis, and siting of an OFEF in an area of minimal storm activity is 

 more than likely important for its economic success and survival. It is probable that future 

 technology will allow placement of the farm in areas of high-storm frequency but the resulting 

 higher costs may dictate selection of areas of low-storm frequency and severity. 



