Daphnia Magna Question

[deleted-297613]

Hello, I have been conducting an experiment with Daphnia Magna and caffeine, and have approached an interesting problem. After exposing them to both Black coffee, and Monster energy drink, I have noticed that their heart rate have actually depressed and dropped in levels. How different are the metabolisms from human to daphnia? Any and all help is appreciated, thank you.

[deleted-224136]

Hello,
I'm not really sure why that would be happening. I found this great article (http://www.nuffieldfoundation.org/pract ... te-daphnia) that goes a bit more into the science of how caffeine affects daphnia. It seems that past research suggests it would increase heart rate.
The only reason I could think of is if the caffeine is becoming toxic to them OR if they're in shock from the added dose. I would try doing a dose curve and adding various concentrations of caffeine, but starting off with a very lose concentration.

I hope this helps.