2012 SURF: Growth Response of Prochlorococcus
Growth Response of Prochlorococcus to Different Nitrogen Sources
Mentor: Dr. Lisa Moore, Biology Department
Prochlorococcus is an important microbe in the marine microbial community because it serves as the base of the marine food chain, providing a food source for small grazers such as ciliates. Prochlorococcus produces 20 percent of global oxygen via photosynthesis and for this reason it plays a big role in carbon dioxide (CO2) fixation and the global carbon cycle. Prochlorococcus also participates in the recycling of organic matter and may provide extracellular organic products that support growth of some marine bacteria.
In a comparison of different strains of Prochlorococcus and their closely related marine cyanobacteria, Synechococcus, it was found that both can use ammonia (NH3) and urea but only some strains of Prochlorococcus can grow on nitrite (NO2-) while no Prochlorococcus strains can grow on nitrate (NO3). However in the last decade several new strains have been isolated that can use nitrate.
Being the most abundant photosynthetic microbe in the oceans, understanding Prochlorococcus is vital to our existence. This study of nitrate-utilizing Prochlorococcus strains involved obtaining axenic strains (without heterotrophic bacterial contaminants), collecting biomass for sending to MIT to check for multiple strains in axenic cultures, and studying nitrogen utilization.