Science Buddies: "Ask an Expert"

I'm using a digital endoscope to view Daphnia magna for a project, and I'm having a tough time keeping track of heartbeat because my Daphnia keep moving around. Also, I am testing the effect of green tea on Daphnia, and when I try to view the Daphnia in the green tea solution, it is even harder to see the Daphnia because the solution is dark green. What I usually do is let a single Daphnia swim around in a drop of green tea solution for a bit, and then I transport it to a drop of spring water to see it more clearly. Still, the main problem I'm having is keeping track of Daphnia heart rate while it's moving around. Is there any way to mitigate this problem? Thanks.

Hello!

This sounds like an interesting project! Have you tried placing a few threads from a cotton ball on top of the Daphnia to prevent them from moving around? I've never worked with Daphnia myself, but I've heard of some people doing this to help keep the Daphnia in place while measuring their heart rate.

I hope this helps!
Katelyn

Thanks, I'll try that out!