deptho The coldj rich phosphate waters below the thermocline approach 

 nearest to the surface at about 9*^ or lOTI at the boundary between the 

 North Equatorial and Equatorial Countercurrent„ 



Probably of greater importance to phytoplankton production is the 

 distribution of inorganic phosphate in the "mixed layer" above the 

 thermocline. The greatest enrichment of the surface layer is in the 

 immediate vicinity of the equator o From this region northward the 

 concentration decreases to a value of about o4-/J g ato/l, and remains 

 nearly constant thereafter. There is no evidence that any enrichment 

 of the surface layer is occurring at the boundary between the North 

 Equatorial and the countercurrento 



The eddy appears again on the eastern section „ A rising of the 

 ,4.ug ato/lo iscpleth toward the surface at 15*T^ and a local maximum 

 of something greater than o^jjg at„/l, at a depth of about 50 m, are 

 shown, but a word of caution should be injected. This particular 

 feature (the o4-/Jg ato/lo isopleth) is drawn entirely on the basis 

 of a pair of inorganic phosphate determinations from a single water 

 sample o The two values obtained were 0„4.9 and 0o72yUg at./l<=» the 

 difference between these values being much greater than the spread 

 between average pairs of determinations. The mean value of o6'^yu g at./l« 

 is not reliable but has been included in accordance with the policy of 

 ignoring only those values which are known definitely to be in error o 



This point is discussed at such length because of the possibility 

 that horizontal eddies at current boundaries may result in vertical 

 movements to produce an enrichment of waters near the surface o The 

 dubious phosphate determination is not considered to be evidence in 

 support of or against this view. 



The isohalines in the eddy are more complicated than those at a 

 comparable latitude in the western cross sectioHo 



Levels of minimal oxygen concentration are represented on FigSo lU 

 and 15 by dashed lines. All levels above and below which the oxygen 

 concentration increases are drawn if the minimum layer so defined appears 

 on two or more consecutive stations. Double and triple minima were 

 encountered at some stations. 



INFORMAnON FROM liVIRE ANGLES 



Wire angles are given with the tabialar summary of data for each 

 hydrographic station. It was necessary to occupy a number of stations 

 near the equator while under power "upstream" to keep the wire angle 

 down. The angle would have been at least 60 in these cases had the 

 vessel not been underway. 



Wire angles in the countercurrent are generally small compared to 

 those in the swift parts of the North and South Equatorial Currents. 

 That this should be true is quite reasonable when the forces tending to 



