Number of cyanobacteria in Toolik Lake at 1 meter depth during June, July and August 1996. Samples were transported to the Dept. of Fisheries and Oceans in West Vancouver, British Columbia, Canada for analysis.
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Lake water was collected from the Toolik Lake main station at 1 m depth and preserved with 2%
glutaraldehyde. Samples were transported to the Dept. of Fisheries and Oceans in West Vancouver, British
Columbia, Canada for analysis. Twenty ml aliquots were filtered onto 0.2 black polycarbonate membrane
using a 25 mm filterholder, with vacuum pressure kept to less than 5 kPa. Filters were transferred to a
microscope slide and mounted with nonfluorescent immersion oil. Cells were counted at 1000x
magnification using a green-yellow (520-560 nm) excitation filter with an epifluorescence microscope.
Cell volumes were estimated by measuring the dimensions of subsets of cells with an eyepiece micrometer.
Calculations for cell volumes were done using formulae for geometric shapes approximating the shapes of
the cells. Synechococcus and Microcolonial Synechococcus assumed spheres with average cell
diamter 0.9 mm; Oscillatoria assumed cylinder with 0.8 mm width x average length.
Reference Citations: MacIsaac, E.A. and J.G. Stockner. 1993. Enumeration of phototrophic picoplankton by autofluorescence
microscopy. In Kemp, P., B.F. Sherr, E.B. Sherr and J.J. Cole (eds.) Handbook of Methods in Aquatic
Microbial Ecology, lewis Publishers, Boca Raton, pp. 187-197.
Version 3: Updated metadata sheet to newer version (with sites sheet). CH April 2013.
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