Counting, counting, counting.


Viral concentrates serve the purpose of creating a fingerprint of the community structure, but raw counts serve a simpler, yet incredibly significant purpose. By counting the microbes, I am able to begin to understand the most general of changes within the Grim Dell.  Enumeration of microbes was done for every field sample collected this summer.

To do abundance counts of microbes, I use a nucleic acid stain, SYBR Gold, to stain the viruses and bacteria in the sample.  Then I make slides using the stained microbes and examine them under an epifluorescence microscope.  If I’m lucky, I can use a program to count the VLPs (Virus Like Particles) and bacterial cells.  If I’m not, I count them manually.

The ability to use counting software is highly dependent upon the clarity of the GD water that day.  On days in which the amount of soil particles in the water is high, the counting software becomes unable to effectively differentiate between microbes and soil, although the human eye generally can.  Manual counts are unpleasant, but count data provides invaluable eyesight into shifts in microbial density. It’s one part of a greater puzzle.