Abstract
A continuous culture apparatus (turbidostat) in conjunction with a controlled spectrum light source was employed to measure the maximum specific growth rates (K (subscript c)), chlorophyll a/cell and ¹⁴C uptake of Isochrysis galbana and Glenodinium halli. The growth of each phytoplanktar was ascertained over a wide range of cell densities and eighteen irradiation-temperature combinations, after which a standard cell concentration, a temperature, and an irradiation level were established for each species. The K(subscript c) of each species was inversely related to the cell density of the culture, except for an apparent plateau at low cell concentrations. The Chl a/cell of G. halli did not change significantly throughout the cell concentrations tested, while in the case of I. galbana the Chl a/cell changed significantly with cell densities greater than 1.35 x 10⁵ cells/ml. The K(subscript c) of each species followed a continuously changing pattern in relation to the temperature, even within the optimum temperature range, irrespective of the light intensities employed. I. galbana ard G. halli grown in a chelate-free medium and with sublethal concentrations of Hg⁺⁺ and Cr⁺⁺⁺ in steady-state equilibrium were not only affected at different concentrations of Hg and Cr, but the pattern of effect was dissimilar for each species with the different metals. The growth of I. galbana was not affected by Hg until 200 ppb Hg was exceeded, whereupon the K(subscript c) decreased with increased concentrations of Hg and complete inhibition of cell division occurred with 602 ppb Hg..
Freeberg, Larry Roger (1976). The effects of light intensity, temperature, cell density and heavy metals (mercury and chromium) on two marine phytoplankters in continuous culture. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -473260.