The ecology of algae : a symposium held at the Pymatuning Laboratory of Field Biology on June 18 and 19, 1959 ecologyofalgaesy00tryo Year: 1960 e c a. o — 2 HEAN From Bartsch, 1956 2 AM 8 II t!oo:i B a. (X c m o m 8 II PM INFLUENCE OF DIFFUSED DAYLIGHT OH SAMPLE CONTAIN IMG ALGAE - AUGUST 26, 1955 Figure I I Center, and perhaps elsewhere. Three areas of relationship between algae and the test are of particular interest. They are: (a) the effect of illumination, (b) quan- tity of algae, and (c) the influence of dead as op- posed to living algae. Water from the Ohio Riv
The ecology of algae : a symposium held at the Pymatuning Laboratory of Field Biology on June 18 and 19, 1959 ecologyofalgaesy00tryo Year: 1960 e c a. o — 2 HEAN From Bartsch, 1956 2 AM 8 II t!oo:i B a. (X c m o m 8 II PM INFLUENCE OF DIFFUSED DAYLIGHT OH SAMPLE CONTAIN IMG ALGAE - AUGUST 26, 1955 Figure I I Center, and perhaps elsewhere. Three areas of relationship between algae and the test are of particular interest. They are: (a) the effect of illumination, (b) quan- tity of algae, and (c) the influence of dead as op- posed to living algae. Water from the Ohio River containing limited quantities of phytoplankton was incubated in an uncovered water bath at 20°C at an east window. Half the bottles were exposed to daily fluctuations in natural light; the others were covered with opaque material. At the same hour each day, duplicate bottles of each group were processed for concentration. The 13-day record is shown in Figure 10. The five-day , after more closely simulating natural conditions, is only about half that derived by closer adherence to the standard procedure. The fluctuation in that occurred during the first five days resulted from intermittent sunny and cloudy weather. With continuous illumination, there was generally an ex- cess of dissolved oxygen in the sample. In another test, when replicates were incubated in the dark for 19 hours, the was ppm. , but with natural light it was only 1 .15 ppm. Furthermore, as shown in Figure 11, the mean of sam- ples processed only at noon would have been, for those illuminated, ppm., but for those in the dark, ppm. - a difference of 400! It is ap- parent that incubation in neither continuous light nor continuous darkness can effectively adjust for the photosynthetic and oxidation reactions related to algae. To explore the influence of plankton quantity, samples were prepared so that one con- tained the phytoplankton removed from 20 vo
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