Guerra, O. J. Texas A&M University, ojg99947@batman.tamucc.edu
Hewes, C. Scripps Institution of Oceanography, chewes@ucsd.edu
Wieland, J. D. Scripps Institution of Oceanography, jwieland@spg.ucsd.edu
Cheng, S. C. Scripps Institution of Oceanography, sccheng@spg.ucsd.edu
Reid, F. Scripps Institution of Oceanography, freid@ucsd.edu
Mitchell, B. G. Scripps Institution of Oceanography, gmitchell@ucsd.edu

 
MICROSPECTROPHOTOMETRIC ESTIMATE OF CELLULAR CHLOROPHYLL IN NATURAL POPULATIONS OF THE DINOFLAGELLATE LINGULODINIUM POLYEDRA
 
A significant issue in modeling aquatic photosynthesis is a lack of information on the detailed optical properties of individual species, and their contribution to total chlorophyll. We present here a method for determining chlorophyll concentrations in a single species of a mixed phytoplankton assemblage, which holds promise for more precise partitioning of chlorophyll into the functional components of phytoplankton models. Water samples collected at Scripps Institution of Oceanography Pier during the summer of 1998 were analyzed for total chlorophyll, species composition, large phytoplankton abundance, size distribution using a Coulter Counter Multisizer, and absorption by total particulates and by individual cells. The average absorption efficiency factor (Qa) of L. polyedrum was 0.8 and 0.5 at the 435 and 675 nm chlorophyll peaks, respectively. We used cell diameters based both on microscopic and Coulter Counter methods, the mean, measured Qa(675) = 0.5, and literature estimates of dinoflagellate unpackaged in vivo chlorophyll specific absorption at the read peak to solve for the cellular chlorophyll concentration of the L. polyedrum population. The data were introduced into the Mie theory as summarized by Morel and Bricaud (1991) to allow us to estimate species-specific cellular chlorophyll concentrations of L. polyedrum.
 
Day: Thursday, Feb. 4
Time:
Location: Sweeney Center
 
Code: CS62TH1692S