Sunday, January 17, 2010

Our Holiday Algae Experiment

Over the Holidays, Pierce and I ran a home experiment with phosphorescent algae. Phosphorescent algae are, in essence, single-celled plants that live in the ocean. When stirred up a bit they glow, but only at night. This is a result of a simple chemical reaction in the algae that produces light as a byproduct - a similar reaction occurs in glow sticks. When stirred up during the day (in a dark room), they don't. This observation forms the core of the experiment: do the algae have a "biological clock" and can it be reset? Can we "train" the algae to glow during the day? Another question: is the presence and absence of light required to support phosphorescence?

For $35 (including shipping) we got 9 test tubes of algae, Pyrocystis fusiformis, via overnight Fedex from Sunnyside Sea Farms in California.

Here's a brief video clip showing how they sparkle and glow. The algae glow green to our eyes but the camera's sensor interpreted it as blue.

Pierce and I put together the experimental apparatus, dubbed the "ACEB-3000" by Pierce (Algae Confusion Experiment Box). Note the confused algae looking at his watch.

The box contained three smaller boxes: one contained 3 test tubes that lived in the dark for the duration of the experiment, 3 test tubes that lived in the light for the duration of the experiment, and one that contained 3 test tubes that lived in a light/dark cycle that was opposite to what the algae were used to.

Unlike the previous science demonstrations (electrolysis of water, strawberry DNA extraction, and yeast balloon - sorry, we neglected to blog about this one), this was a little closer to a true experiment since it involved hypothesizing how the algae might behave during the course of the experiment, logging data at regular intervals (3 times a day over 5 days), analyzing the results, identifying potentially anomalous results, and discussing how the experiment could be improved if we were to run it again.

Here's the graph of the results showing that we were able to quickly change the algae clocks. It also shows that the both the all-dark and all-light algae were able to phosphoresce, albeit feebly. Click on the photo to enlarge.