Algal Growth in Crossed Gradients of Light Intensity and Temperature.

Growth characteristics of selected thermophilic strains of cyanobacteria using crossed gradients of temperature and light

“…The use of gradients, either singly or in combination (temperature, light, pH, salinity, nutrient concentrations) can simplify and accelerate the selection of appropriate conditions. Cultivation of algae in crossed gradients of temperature and light (Halldal & French 1958;Yarish et al 1979;Lukavský 1982,) proved to be a suitable method for the testing of morphological variability, growth rates, metabolite content, and levels of photosynthetic pigments. A large number of combinations of temperature and light, together with a wide spectrum of growth conditions can be tested simply and quickly in one unit at the same time (Lukavský 1982).…”

Temperature responses of a coccolithophorid, Cricosphaera carterae, measured in a simple and inexpensive thermal‐gradient device1

“…They produced nonlinear thermal gradients, in contrast to those devices having both a heat source and a heat sink which produced nearly linear gradients (e.g. Edwards and van Baalen 1970;Halldal and French 1956;Jitts et al 1964). Although strict linearity may be of some advantage in setting up experiments, our nonlinear gradient presents no serious difficulty since, once stabilized (in 1 or 2 h), its temperature regime is easily charted for future reference.…”

“…Larger vessels could be stirred by magnetic stirrers below the aluminum plate. Adding strips to the Notes upper edge of the aluminum plate could convert it into a shallow tray in which a continuous gradient on agar could be produced, like that described by Halldal and French ( 1956). The apparatus could also be made to include a light gradient, by use of neutral-density filters or by widening the plate and mounting the fluorescent lights over one edge.…”

“…Edwards and van Baalen (1970) and Halldal and French (1956) used heated covers to reduce the formation of condensate. In our experiments some moisture condensed on the caps and upper parts of the vessels, especially those at the higher temperatures, somewhat reducing the light intensity inside the vessel and changing the concentration of solutes in the medium.…”

“…Thermal-gradient devices have been described for the culture of various microorganisms. For culturing algae, a light gradient can be superimposed at right angles to the temperature gradient (Edwards and van Baalen 1970;Halldal andFrench 1956, 1958;Jitts et al 1964). Most devices are based on the use of an aluminum rectangle heated at one end and cooled with a heat sink at the opposite end, although some bacteriological devices, designed for high-temperature work ( e.g.…”