9602462 Capone This award provides support for a 3 month National Science Foundation Dissertation Enhancement Award for Douglas Capone at Tokai University, School of Marine Science and Technology. Dr. Capone's student, Ms. Margaret Mulholland will work with Dr. Kaori Ohki, Professor in the School of Marine Science and Technology, on a research project entitled, "Regulation of N2 fixation in Trichodesmium". Trichodesmium spp. are N2 fixing, marine cyanobacteria that occur throughout the tropical and subtropical oceans in areas otherwise noted for their paucity of plant life. As for many terrestrial systems, limitation of oceanic plant production is attributed primarily to a shortage of utilizable nitrogen compounds. Trichodesmium spp., utilize dinitrogen gas, the most abundant form of nitrogen, thereby alleviating nitrogen limitation and providing new nitrogen input into these systems. Trichodesmium spp. can sustain high rates of N2 fixation in nature; however, little is known about the biochemical and physiological conditions that support N2 fixation in these species since they have been difficult to maintain in controlled culture systems. Professor Ohki and her collaborators have been successful in their attempts to grow Trichodesmium in cultures,but transfer of this culture to other laboratories has proven unsuccessful. This project will examine the cellular regulation of N metabolism and N2 fixation in Trichodesmium NIBB1067 grown under controlled conditions with and without fixed nitrogen compounds. Results from these studies will be compared with results from the field in order to better understand the natural populations of Trichodesmium. ***
