PRINCIPAL 



INVESTIGATOR(S) Robert J. Olson 



Biology Department 



Woods Hole Oceanographic Institution 



Woods Hole, MA 02543 



PROJECT TITLE PHOTOSYNTHETIC ENERGY CONVERSION EFFICIENCY 



IN INDIVIDUAL PHYTOPLANKTON CELLS FROM "PUMP 

 AND PROBE" FLOW CYTOMETRIC MEASUREMENTS 



AMOUNT OF FUNDING FY 1994: $236 K 



SUMMARY OF GOALS 



To develop an instrument to determine photosynthetic energy transfer efficiency in 

 different groups of phytoplankton from natural samples, and to use this instrument to characterize 

 the nutritional status of these cells in different oceanographic regimes. Such an instrument will 

 supplement measurements of active fluorescence by existing Fast Repetition Rate instruments, 

 which measure photosynthetic parameters on bulk water samples. 



SPATIAL AND TEMPORAL SAMPLING SCALES 



We will measure samples from depth profiles at stations in nearshore to open ocean 

 waters, and over seasonal time scales (on process study cruises). We are not planning for in situ 

 sampling or moored operation. 



METHODS AND PLATFORMS 



The methods employed will be the pump-probe flow cytometer under development, which 

 will require a small to mid-size oceanographic vessel (e.g., RV Oceanus). The samples will be 

 analyzed at sea, but not in situ. Comparisons with FRR measurements and other productivity 

 measurements will be an important part of the study. 



STRENGTHS AND LIMITATIONS OF PROPOSED RESEARCH 



The main strength of the approach is that it will allow us to examine individual 

 phytoplankton cells (or particular groups within the phytoplankton) as opposed to bulk water 

 samples containing variable mixtures of cells and detritus, etc. This should increase the 



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