PRINCIPAL 



INVESTIGATOR(S) John H. Paul 



Department of Marine Science 

 University of South Florida 

 830 First St. South 

 St. Petersburg, FL 33701 



PROJECT TITLE REGULATION OF PHOTOSYNTHETIC CARBON FIXATION 



ON THE OCEAN MARGINS 



AMOUNT OF FUNDING FY 1994: $58 K 



SUMMARY OF GOALS 



The goals are to 1) understand regulation of ribulose bisphosphate carboxylase (RubisCO) 

 in phytoplankton cultures in response to light regime 2) determine regulation of RubisCO in 

 response to light during nutrient limitation in these cultures 3) to determine mechanisms of 

 RubisCO regulation in natural populations of phytoplankton on the ocean margins in the Gulf of 

 Mexico and 4) to measure regulation of RubisCO in phytoplankton of the Hatteras System. Two 

 goals are laboratory-based, and two are ship-based. 



During the first year, the Tabita lab is primarily responsible for objectives 1 and 2 of the 

 overall project (see above). Specifically, we have initiated experiments to probe the regulation 

 of RubisCO in response to different light and nutrient limitation conditions in representative 

 marine cyanobacteria and diatoms. These studies have been performed to understand the factors 

 that control RubisCO gene transcription and RubisCO activity, and to relate these molecular 

 perturbations to changes in the marine environment that influence overall C0 2 and carbon 

 metabolism. 



SPATIAL AND TEMPORAL SAMPLING SCALES 



Participation in DOE cruises is highly desired. We would be interested in spatial sampling 

 across the shelf in conjunction with the spring bloom at least 4 stations along a transect (for 

 vertical profiles). During a second cruise, diel regulation and regulation under various light 

 regimes is required for us to complete our DOE mission. These studies last 24-48 hr/diel with 

 sampling every 4 hr. 



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