Palenik, B. P. University of California, San Diego,
Toledo, G. P. University of California, San Diego,
Brahamsha, B. University of California, San Diego,
Goericke, R. University of California, San Diego,

Environmental variables such as light, temperature, and nutrients seem to be influencing cyanobacterial genetic diversity in marine ecosystems, but to an extent that is still poorly characterized. These issues can be addressed by examining the distribution of clades in situ relative to environmental variables. Alternatively physiological characterization of strains in the laboratory may provide hypotheses as to how these cyanobacterial clades are responding to their environment. We have examined the growth rate of six Synechococcus strains as a function of light intensity and nitrogen source. There are significant differences in growth rate among the strains under the same conditions. Four strains grow noticeable better on urea than nitrate suggesting that nitrogen may be an important variable affecting diversity. Pigments in the strains were typical of Synechococcus (Chl-a, beta-carotene, zeaxanthin, phycoerythrobilin, and phycourobilin), but some variations in pigment ratios were found. Interestingly, two strains in one genetically-defined cluster are able to chromatically adapt by increasing their phycourobilin to phycoerythrobilin ratio when grown under blue light. This capability suggests that these strains may have a competitive advantage when significant mixing occurs.
Day: Tuesday, Feb. 2
Time: Poster
Location: Sweeney Center
Code: SS40TU0299S