Measuring photosynthesis: From marine bacteria to terrestrial ecosystems
Zbigniew Kolber, Ph.D.
Wednesday, June 19, 2002
3:00 p.m.–Pacific Forum
Fluorescence is the most ubiquitous and the most convenient indicator of physiological status in photosynthetic organisms. The fluorescence yield is controlled, to a first degree, by the level of photosynthetic activity. Manipulating this activity using an artificial excitation source and analyzing the stimulated changes in the fluorescence signal allows us to characterize a suite of photosynthetic properties such as the efficiency of light utilization, the yield of charge separation, and the kinetics of the photosynthetic electron transport.This methodology is transcendental to both marine and terrestrial environments and extends to microbial photosynthesis, including aerobic and anaerobic bacteria. I will present the fundamentals of fluorescence methodology and describe its applications in marine environments, with particular emphasis on recently discovered bacterial photosynthesis in the upper open ocean. Implementing this methodology toward remote, continuous measurements of photosynthesis on a global scale will allow the energetical component of the global carbon cycle to be constrained in a model. I will discuss the technical feasibility of such an endeavor.