APPENDIX D: BRANWl" _ 19 — 



summer. From the analyses of the chemical composition oT planJiton-organisms, which 

 Dp. Stiehr has carried out at Kiel during the past year, it has been determined, just as 

 for land-plants, that Ceratium and Rhizosolenia require about 2*5 times as much nitrogen 

 compounds as phosphates. Less phosphoric acid is thus absorbed than nitrogen. At 

 the time when it is at a minimum therefore, the phosphoric acid must be present in 

 the sea in still smaller quantities than the nitrates. We must remember, however, that 

 owing to the high molecular weight of the phosphates, the absorption-coefficient for these, 

 according to the law of osmosis, will be smaller than for the nitrates. 



