Elemental analysis of single phytoplankton cells using the Lund nuclear microprobe

The occurrence of annual marine phytoplankton blooms is becoming a global p roblem. In Europe, the NUTOX project supported by the EC investigates if un balanced nutrient compositions in the water promote the dominance of harmfu l phytoplankton species. One of the tasks is the determination of the eleme ntal composition of single phytoplankton cells. This is carried out using t he Lund Nuclear Microprobe with a special focus on C, N, P and K. The overa ll aim is to understand the mechanism leading to toxin production, model it and eventually propose a counteracting method. The preparative method, use d to isolate single living cells while reducing their salt environment, is an important part of the analytical procedure. A comparison of light elemen t detection using backscattering from protons and nuclear reaction analysis using deuterons is made. (C) 1999 Elsevier Science B.V. All rights reserve d.