Information gathered from these measurements will help provide the capability to estimate the 

 dynamics of primary production and identify its limiting factors, and simultaneously constrain 

 the phytoplankton pool and the carbon fluxes surrounding it. 



The success of the moored application will depend on our ability to control the fouling 

 of the optical windows in the moored instrument. We have developed brush mechanisms to keep 

 optical windows clean, and we plan to install such a mechanism on the moored version of the 

 FRR fluorometer. 



STATUS OF RESEARCH 



Several FRR fluorometers were field-tested during the 1993 OMP cruise. The discrete, 

 underway mapping, profiling, and TOYO configurations performed as expected. FRR estimates 

 of primary production correlated well with 14 C measurements. A moored FRR fluorometer was 

 deployed near Cape Hatteras in March 1994. Following its recovery in July 1994, the 

 instrument's performance will be critically evaluated with regard to long-term calibration. 



Two laboratory investigations are being conducted as part of the FRR project. There is 

 a continuing effort to relate fluorescence and photosynthesis by comparing FRR fluorescence to 

 oxygen production. A fluorescence time-resolved study on the biophysics of photosynthesis using 

 the BNL National Synchrotron Light Source is continuing as well. The results of this effort will 

 be used in further development of the FRR protocols. 



In Phase U of OMP, we propose to become a basic research component, directed toward 

 understanding the mechanisms of photosynthesis, the relationship between photosynthesis and 

 fluorescence, and the effects of environmental factors on the functioning of photosystem II in 

 marine phytoplankton. 



Keywords: photosynthesis, primary production, fast repetition rate fluorometer 



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