Phosphorus and Silicon in Sea Water off Plymouth During 1956

Abstract

The results of analysis of sea water from the International Hydrographic Station E1 during 1956 are presented in graphical form and as integral mean values for the water column of 70 m. The seasonal variation is shown; it appears that consumption of phosphate in the spring outburst of plants was 0·34 μg atom P/l., and that of silicate 2·78 μg atom Si/1. The spring outburst was followed more closely than usual in the period 26 March to 24 April during 4 weeks of rather bright weather. Nearly all the silicate in the water was taken up, and some phosphate left, and it seems that the rapidly growing diatoms, which predominated at the time, were deficient in silicon. It is suggested that in the deep water they continued to absorb silicate, although not receiving enough light for growth and division.