Uptake by the Marine Dinoflagellate, Gonyaulax polyedra, of Radioactivity Formed During an Underwater Nuclear Test

As part of the general study, we planned to measure the uptake of fission products by one element of the marine biota, the marine phytoplankton. We hoped to isolate single, naturally occurring phytoplankton cells after the test explosion and measure their radioactivity, and also to measure the activity taken up from radioactive sea water by unialgal diatom and dinoflagellate cultures maintained aboard the ship. However, the cultures failed to survive under shipboard conditions and technical difficulties in isolating phytoplankton at sea were experienced. Thus, these approaches were discarded, and, instead, radioactive sea water was transported back to the Scripps Institution of Oceanography by one of us (F. T. Haxo) so that uptake could be measured under more favorable conditions. The experiments described were conducted during the period 20 to 30 May 1955, to determine the amount of radioactivity taken up by laboratory cultures of the coastal marine dinoflagellate, Gonyaulax polyedra Stein.