TITLE:  Molecular fingerprinting to understand diazotrophic microbe distribution in oligotrophic oceans

ADVISOR:  Professor Carlos Duarte

DATE:  23rd July

TIME:  9 am

LOCATION: Auditorium (level 0) between buildings 4 and 5

ABSTRACT:  Nitrogen is an essential element to life, but the most abundant form of nitrogen on Earth, dinitrogen gas, is not readily usable to most living organisms. In order to ensure the constant supply of nitrogen in oceans, planktonic diazotrophs, comprising of various prokaryotes, work as free-living organisms or in symbioses with host organisms, to convert dinitrogen gas in the atmosphere to bioavailable forms. The conversion of dinitrogen gas to more usable forms of nitrogen such as nitrate and ammonia is known as nitrogen fixation. In oligotrophic systems, where primary production is low and nitrogen is in short supply, nitrogen fixation process is intense. Although a few diazotrophs (eg. Trichodesmium) have been widely studied, the rest of the diazotrophic community is still poorly understood. Furthermore, the global distribution of diazotrophs are yet to be clearly resolved. This dissertation assessed the distribution of diazotrophs in oligotrophic systems, particularly in the tropical and subtropical oceans, using genomics tools including next-generation sequencing.