Significance of Nannoplankton

Abstract

ATKINS¹, in 1945, reported on the productivity of the English Channel as estimated by two independent methods. The silicate turnover indicated a far lower productivity than did the phosphate turnover, and from this he deduced that only a relatively small fraction of the phytoplankton could consist of forms with siliceous skeletons. Knight-Jones and Walne² later showed that the very small nannoplanktonic form, Chromulina pusilla, was present in English Channel waters in numbers averaging about 1,000 per ml. They quoted other work showing that as much as 90 per cent of the phytoplankton may be small enough to pass through a fine silk tow net, and 40 per cent through a No. 2 Whatman filter paper.