Science Buddies: "Ask an Expert"

Hi,
I have measured the absorbance of phytoplankton cell suspensions in different iron concentrations using colorimetry, every 2 days, for a period of 6 days. I have decent results for all six concentrations (absorbance increased for increasing Fe concentrations). However, I intended to find the rate of photosynthesis using just the absorbance values, is this still possible? What can I find out using my results?
All help would be appreciated!
Thanks!

Hi there,

From your information on the right side of your post, it seems that your project due date was on January 3rd. If that is true, we're really sorry that you didn't receive a reply before your project due date! However, if you still need help or have other questions, we would be glad to help you. It would be a good idea to post your questions well before your deadlines to the best of your ability to ensure that any experts that sign onto the forum can get back to you before your project is due.

I don't know too much about photosynthesis, so it would be very helpful if you provide a little more details about your project, what your question and hypothesis are, and the experiment you used to test your hypothesis so I can provide you with as much helpful advice as I could. From the looks of what you just posted, are you trying to see how different iron concentrations affect the rate of photosynthesis of phytoplankton? That is a very interesting question! How did you decide to use absorbance as a readout for your experiment? Have previous studies been done where scientists use absorbance values as a readout for photosynthetic rates? If the rate of photosynthesis is faster, do you see an increase in absorbance values? What wavelength of light are you shining on your samples to obtain the absorbance values?

Please post back with more questions if you need any more help, and sorry again if we didn't get back to you in time before your deadline!

Best,
Connie