LONG-TERM GOALS

This project studied the influence of iron nutrition on the physiology and molecular ecology of marine cyanobacteria and their resultant effects on seawater optical properties. The influence of iron on marine primary production is now known to rival that of nitrogen. Given iron’s integral part of photosynthetic metalloproteins, this element can have a strong effect on the pigmentation of phytoplankton. The marine cyanobacteria, including Prochlorocococcus marinus and marine Synechococcus, are among the most abundant phytoplankton in the oceans, and hence contribute significantly to both carbon cycling and ocean optical properties. Through this Office of Naval Research Young Investigator Award (ONR-YIP), our laboratory has studied the iron requirements of these marine cyanobacteria and their physiological, optical and molecular characteristics. Because Prochlorococcus is relatively difficult to grow and pure cultures were only recently produced (Saito et al., 2002), studies of the elemental composition and requirements of this key phytoplankton species have not been possible until recently. Yet, global ecosystem models have been lacking necessary iron growth parameters for this key phytoplankton group that are needed to improve the predictive capability of marine primary productivity and the seawater optical properties (Aumont et al., 2003