Counting algae

When you are trying to do research at a community college, the little things can be challenging.  Like counting cells.  Pretty soon its going to be really important that I be able to count algal cells pretty danged accurately in order to have my students hunt for algal viruses in local streams and ponds.  This can be done indirectly by using a spectrophotometer to measure the amount of light that a tube of cells absorbs/refracts (especially if they are green, like algae), and multiplying the amount of light absorption by a known constant that gets you back to cell number (cell number and amount of light absorbance should be directly correlated) – but that isn’t a direct count.  Back in the day I counted cells many times every day. Its really important when you are doing virus infections to know exactly how many you have in your plate.  But in research labs you do this with a counting slide or hemocytometer, which cost over $400 for one slide, so it seems unlikely that we would have that here.

Until your colleague shows you a box of miscellaneous  microscope stuff in it hidden in a drawer:

happy 2

This might not be obvious, but this is a gold strike for me.  Don’t worry, this project has nothing to do with sperm. Or bacteria.

happy counting

  It might not look impressive, but those lines tell you the exact volume of liquid you are looking at, so once you count your cells, you divide it by that volume (you are looking at approximately 0.00008 ml) and bazinga, you are done.  The little green dots are Chlorella, the green algae.

Just in case I forget the math.

183,750 cells/ml, by the way.


About SubOptimist

I am an Associate Professor in the Science Department at Georgia Perimeter College, Clarkston. I teach introductory biology courses at both the majors and non-majors level in addition to microbiology. Previous to that I spent 7 years as a postdoctoral researcher on different viruses. While I don't miss being on the "grant treadmill", I think better when I write and miss writing up data for papers and grants; this blog helps me with that a little. And sometimes my kids' insanely funny and cute antics need to be shared with the world. Any view expressed in this blog is that of me personally and not Georgia Perimeter College or the GPC Clarkston Science Department.
This entry was posted in Algae, Chlorella Virus Project. Bookmark the permalink.

8 Responses to Counting algae

  1. Amanda Laden says:

    I am extremely jealous of you right now. You found a hemocytometer in your lab! I’ve been digging around in my high school storeroom in the hopes of making the same discovery. But so far no luck. I wanted my students to design experiments to find the effect of a variable (light, heat, fertilizer) on population growth of Chlorella. To have quantitative data would be amazing. I purchased some disposable hemocytometers at $6.70 per slide in the hopes that I could clean them out with compressed air. That worked well except that the high pressure broke the plastic cover near the edge – now the volume of liquid in the space isn’t accurate. Good luck to you with your newly found reusable hemocytometer(s)!

    • SubOptimist says:

      How’s it going with your students? I was never able to get my cultures to the point where it was ready to have my students work on it…. did you have any success?

      • Amanda Laden says:

        I ordered Chlorella from Carolina Biological Supply Company. I kept the test tube in the container for a couple weeks with the cap loosened for air exchange. The culture grew so dense, I needed to dilute it for students to use. It worked well. I get the same clumping problem that Areeg mentioned when I grow it in a shallow aquarium. I tried unsuccessfully to use a stir bar to break up the clumps. I may simply order Chlorella cultures from supply companies until I figure out how to avoid the clumping.

      • SubOptimist says:

        Interesting. I got my cultures from the Van Etten lab at UNL and had no such clumping when I grew them in liquid media. They arrived on agar slants, which is how the Van Etten lab maintains them. I believe I tried to grow the Carolina strain on agar slants (using an autotrophic media) and they just wouldn’t. What media are you growing yours in… the pond water autotrophic media (can’t remember the name) from Carolina?

      • Amanda Laden says:

        Yes, they call it Alga-Gro. I have no idea what’s in it.

      • SubOptimist says:

        Exactly what I used.

  2. Areeg says:

    Hi, my name is Areeg and i would like your assistance on seeing chlorella vulgaris using a haemocytometer. when i try to view the cells they are all in clumps and i count them clearly as i do on a normal flat slide. i wanted to ask if you use a certain protocol to view the cells clearly, i can email you a picture to demonstrate my problem more clearly.Thank you for your time.
    kind regards,
    Areeg .M.

    • SubOptimist says:

      Hello – Sorry for the extreme delay in getting back to you. First, I am not at all an expert on this…. my attempts to grow Chlorella were not exactly successful… Having said that, I am not sure why your cells are clumping… mine always were nice single cell suspensions. What kind of media are you growing them in?

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