PRINCIPAL 



ESVESTIGATOR(S) David A. Caron 



Biology Department 



Woods Hole Oceanographic Institution 



Woods Hole, MA 02543 



PROJECT TITLE ASSESSING INORGANIC NITROGEN AND PHOSPHORUS 



UTILIZATION BY BACTERIA USING AN 

 IMMUNOFLUORESCENT METHOD 



AMOUNT OF FUNDING FY 1994: $108 K 



SUMMARY OF GOALS 



The goal of my program is to assess the utilization of inorganic nutrients (NH 4 + , N0 3 , 

 P0 4 " 3 ) by bacteria in planktonic ecosystems within the context of OMP. Controversy has arisen 

 in recent years on the role of bacteria as nutrient remineralizers in aquatic ecosystems. The 

 traditional role of bacteria as sources of inorganic nitrogen and phosphorus (via the 

 decomposition of organic matter) has been challenged by the recognition that N and P may not 

 be present in sufficient quantities in the organic compounds used by bacteria for growth. My 

 goal is to develop and apply immunological methods that can be used to assess the physiological 

 status of bacteria and the conditions that promote this behavior. 



SPATIAL AND TEMPORAL SAMPLING SCALES 



Ideally this program will examine the physiological status of bacteria along seasonal, 

 geographical and vertical transects to determine the extent to which bacterial uptake of inorganic 

 N or P exists. My hypothesis is that bacterial utilization of inorganic N and P is promoted by 

 conditions of oligotrophy and is related strongly to the nutritional status of the algae in a 

 particular environment (more severely nutrient-limited algae result in conditions in which the 

 bacteria are also nutrient limited. Therefore, greater utilization would be expected in summer 

 versus winter, offshore (oligotrophic) versus inshore (eutrophic), and in surface populations 

 versus deeper populations during periods of thermal stratification. The sampling regime should 

 be ship-based and provide appropriate spatial coverage: vertical transects of =10 depths, 

 inshore-offshore transects, at least prestratification/poststratification seasonal comparison. Small 

 volume samples (< 1 liter) are anticipated. 



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