Date of Award

Spring 1978

Document Type


Degree Name

Doctor of Philosophy (PhD)


Ocean & Earth Sciences



Committee Director

Harris H. White

Committee Director

Chester E. Grosch

Committee Member

Anthony J. Provenzano

Committee Member

Frank P. Day

Committee Member

George S. Ofelt

Committee Member

John C. Ludwick


In the present study a numerical modeling approach is employed to examine the role of division spedific differences in photosynthetic action spectra in governing the relative size of diatom and dinoflagellate carbon synthesis along various marine light regime gradients. A radiative transfer model taking into account both Rayleigh and Mie atmospheric optical properties is employed to define the light regime incident on the sea surface. The hydrospheric light regime is defined by an exponential decay model with a correction for diffuse back scatter. Taken together, the atmospheric and hydrospheric models define the spectral composition and intensity of light in the sea as a function of solar altitude and depth. This permits the simulation of realistic spectral gradients along various temporal and spatial dimensions of the marine environment: diurnal, seasonal, vertical, and latitudinal. A spectrally sensitive model of photosynthesis is employed to determine the rates at which carbon compounds are synthesized a t various points along these gradients. The ratio (between dinoflagellate and diatom carbon synthesis is determined by taking into account differences in division specific photosynthetic action spectra.


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