16 
CHEMICAL OCEANOGRAPHY (G, Weichart) 
The chemical investigations served two purposes: 
From the distribution of nutrients and oxygen, insight 
may be gained into the location of the upwelling areas 
and into the intensity of the upwelling processes, 
Moreover, nutrients and oxygen are the prerequisites to 
marine organic processes, So, the nutrient content in 
the euphotic layer and the oxygen content below the eu- 
photic layer provide insight into the organic production 
of an upwelling area, From the oxygen distribution it may 
be seen whether there is sufficient oxygen available to 
animal organisms for respiration, 
On four long and four short sections the chemical working 
team determined the dissolved oxygen, dissolved organic 
phosphate and dissolved silicate., Water samples were 
taken by means of plastic Nansen bottles (HYDROBIOS, Kiel), 
The titration method by H, Winkler in the modified form 
after Kalle (1939) was used for the quantitative determi- 
nation of oxygen, The inorganic phosphate was determined 
by means of the blue phosphate-molybdenum method after 
Murphey and Riley (1962); Photometer ELKO II (ZEISS), 
filter S 75 E,. 
The analysis of silicate was made using the silico- 
molybdate method by Robinson and Thompson (1948); Photo- 
meter ELKO III (ZEISS), filter S 42 E, 
From the chemical data it may be seen that upwelling in 
the area of investigation, if present at all, occurs much 
more slowly than in the centre of the upwelling area 
farther south, 
The nutrients phosphate and silicate, if they enter the 
euphotic layer from below, are so rapidly eaten by phyto- 
plankton that their conceniration near the surface remains